My junk is still messed up.

[Andrew]

It still popped and sputtered down the track (the WHOLE way down the track)... but at 15 psi, 21 degrees timing on 118 octane with 90 degree ACTs it went

60': 1.4745
330: 4.0124
1/8: 6.1277
MPH: 116.67

Kinda disappointing. I talked with Jeremy @ HPP about my tuneup and am coming to the conclusion that it's something mechanically wrong with my car. I'm going to rerun the valvetrain and see what that does.

[98DSM]

Whats your A/F ratio? How are the EGT's? You'll get there, just taking abit more time than you would have liked.

[TRAXX]

dang man that sucks. Any clue what it might be? Did you touch the motor at all when you were doing the turbo?

[302_plus_a_few]

Andrew, I wonder how much overlap you have in your cam?

[NDSP]

Check your pms, andrew.

[SSMAN]

Good luck hunting down the problem. Keep us updated.

[93LXHORSE]

Maybe blower cam = no good for the turbo?

[Thehead]

Originally posted by 93LXHORSE
Maybe blower cam = no good for the turbo?

it's possible... try an E or F cam,,, see what happens?????

[spankustang]

Originally posted by Thehead
it's possible... try an E or F cam,,, see what happens?????

lol

[AnotherRedHead]

Do you have a REAL air fuel gauge on it down the track? What does it say?

[STROKD]

Originally posted by 93LXHORSE
Maybe blower cam = no good for the turbo? Ding ding ding...;)

[Ylw 98~~SNAKE~~]

Originally posted by AnotherRedHead
Do you have a REAL air fuel gauge on it down the track? What does it say?

I believe he does i remeber seeing it in one of those videos of him making a pass at the gn vs mustang meet back when he had the vortech on it

[ToRqUeTwIsTeR]

The stock cam will work better than the f cam.....:rolleyes:

*EDIT* :D

[SNEAKY]

Originally posted by ToRqUeTwIsTeR
The stock cam will work better than the e or f.....:rolleyes: Ecam is actually a pretty good turbo cam.

[Carrie]

Originally posted by SNEAKY
Ecam is actually a pretty good turbo cam.

Bryan runs an E cam.

Sorry, you are still having problems Andrew. Are you going to the turbo shootout in San Antonio if you get it fixed?

[aggie97]

I think it would be one of two things. The too small downpipe...really needs to be 5". Or the cam. Turbos like cams that are favorable to N/A motors right? Seems like they need better exhaust valve timing..........?

Spend some money and get a nice custom cam for that thing.

[93LXHORSE]

That downpipe should be just fine - that thing is gigantic.

[Da Prez]

dam andrew that sucks to hear bro, hope you get it all figured out...

[turbostang]

possibly weak valve springs? maybe the boost is blowing the alves open? boost + weak spring + high lift = bang bang.. pop..pop... bang... (you get it)

[Andrew]

Al P brought over a valve spring checking tool... I only checked a couple and it looked like they were about 120# on the seat. They are 130# on the seat from AFM. Maybe that might have something to do with it... or maybe I have a couple that are much worse than that. I'll check the rest of them out tonight.

Originally posted by turbostang
possibly weak valve springs? maybe the boost is blowing the alves open? boost + weak spring + high lift = bang bang.. pop..pop... bang... (you get it)

[Andrew]

Of note is that the car was down for awhile and I didn't back off the rockers... I know that with solid roller springs you're supposed to back the rockers off but I don't know about hydraulic roller springs.

[Boost Addict]

Andrew,

I would really lean toward suspecting those valve springs. 120lb on the seat just isn't enough for the kind of rpm you've gone in the past.....they're probably just worn out and won't sustain the pressure over the top.

I'd look into going solid...then turn 8K rpm!! But I'd at least try a valve spring replacement to see if that will get you by. I know the Renegade guys replace their valve springs quite often and run somewhere around 160 on the seat. I'm going solid with mine now because I was having somewhat similar problems. Car wouldn't make the boost at high rpm and it would bang out a little. My valve springs came in around the 120 range, not near enough considering the over the top pressures the springs see. I had to laugh when I learned my new solid setup is around 230-235 on the seat!

Good luck with it.

[AL P]

Andrew, do you know what spring you have and what installed height they are at? If you do you can calculate what the pressure on the seat should be.

[AL P]

BTw, I would think that with an agressive hydraulic roller you would want about 130 to 160 on the seat.

I know that I have a very light duty solid roller and set mine up for 160 at a 1.850" installed height. And that spring (Comp part# 939) is actually intended for a solid flat tappet cam from what Comp Cams told me.

The best person to ask about seat pressure, of course, would be Rick Anderson.

I also have the Moroso tool to compress the springs on the head, if you need it. As you can tell, I've been messing around with valve springs and such for the past couple of months...

[46Tbird]

120lbs

LOL

[NDSP]

I'm assuming you have logged these passes. Post up a pic of the log. I'm particularly interested in the rpm, timing, AFR, PSI, and fuel map. That is if ya got it. :)

[Andrew]

I do but the computer is at home. I'll get it off and post it up.

Originally posted by NDSP
I'm assuming you have logged these passes. Post up a pic of the log. I'm particularly interested in the rpm, timing, AFR, PSI, and fuel map. That is if ya got it. :)

[46fever]

Big Nasty Solid roller,new valve springs,And bring it to the Shop,We can fix her up.It Always is the simple shit that f's you up.;)

[turbostang]

It just seems that since the car does pop ALL the way down the track that it is most likely a mechanical problem. - The only exception (to me) is the coil? This will be interesting.. be sure to tell everyone what the solution was.. Inquiring minds want to know..:)

[Boss Hogg]

Dot to Dot Karma?

[Andrew]

Doubt it.

Originally posted by David Z28
Dot to Dot Karma?

[NoSlix]

120lbs on the seat is NOWHERE near enough for the amount of boost and rpm you want. Minimum 160, and I'd probably even go a bit higher than that.

[JamesB]

Sounds like your muffler bearing is out.

[Andrew]

I called Rick Anderson and he said that the springs I'm using should be 150 lbs on the seat. He also said that the tool I'm using is nowhere accurate. I'm gonna pop a spring off and measure it to make sure... anyone around here have a precision valvepsring measuring tool? I need to measure the valvespring at 1.800".

Originally posted by NoSlix
120lbs on the seat is NOWHERE near enough for the amount of boost and rpm you want. Minimum 160, and I'd probably even go a bit higher than that.

[93LXHORSE]

So what exactly is happening if the seat pressure isn't enough?

[turbostang]

Originally posted by 93LXHORSE
So what exactly is happening if the seat pressure isn't enough?

they are saying that the boost is blowing the valves open under high boost.

[STROKD]

Originally posted by turbostang
they are saying that the boost is blowing the valves open under high boost. :(

Do valve springs go bad that fast? I have about 20K miles on mine, and they are stock Edelbrock valve springs.:( :confused:

My car isn't banging out, but it does seem to gradually run slower each time I take it to the track. Last pass at Denton, it sounded like it hit the revlimiter at like 6K? would that be the banging out that Andrew is experiencing?:o

[turbostang]

Originally posted by STROKD
:(

Do valve springs go bad that fast? I have about 20K miles on mine, and they are stock Edelbrock valve springs.:( :confused:

My car isn't banging out, but it does seem to gradually run slower each time I take it to the track. Last pass at Denton, it sounded like it hit the revlimiter at like 6K? would that be the banging out that Andrew is experiencing?:o

I guess it depends on how high you rev the motor vs. boost etc... It could be possible with off the shelf springs..

[AL P]

Originally posted by Andrew
I called Rick Anderson and he said that the springs I'm using should be 150 lbs on the seat. He also said that the tool I'm using is nowhere accurate. I'm gonna pop a spring off and measure it to make sure... anyone around here have a precision valvepsring measuring tool? I need to measure the valvespring at 1.800".

The tool is reasonably accurate. Its not a scientific instrument by any means but it will let you know if you have a spring problem with the springs on the head. Based on the comp cams catalog, my springs should have ~183 lbs on the seat at a 1.850" installed height. Mine showed about 165 to 170 on the tool. Thats enough to be able to know if you are close.

If he said 150 and that tool said 120, then I'd bet you got a problem. Did he say how long the springs SHOULD last?

STROKD...how many times you bang the limiter has a lot to do with spring life....heat can hurt them too.

[AL P]

Originally posted by turbostang
they are saying that the boost is blowing the valves open under high boost.

Don't think this could be it unless the springs were really shot.

Supposedly, a really weak spring will let the valve bounce off the seat when it closes.

[turbostang]

Originally posted by AL P
Don't think this could be it unless the springs were really shot.

Supposedly, a really weak spring will let the valve bounce off the seat when it closes.

true dat.. but.. they would sound the same. :)

[Andrew]

I told him that I had ~2 years and 150-200 passes on the springs and he didn't seem concerned.

Originally posted by AL P
The tool is reasonably accurate. Its not a scientific instrument by any means but it will let you know if you have a spring problem with the springs on the head. Based on the comp cams catalog, my springs should have ~183 lbs on the seat at a 1.850" installed height. Mine showed about 165 to 170 on the tool. Thats enough to be able to know if you are close.

If he said 150 and that tool said 120, then I'd bet you got a problem. Did he say how long the springs SHOULD last?

STROKD...how many times you bang the limiter has a lot to do with spring life....heat can hurt them too.

[93LXHORSE]

Ok I can understand bouncing but I was trying to figure out how boost could blow the valves open when they are closing against the top of the chamber and it seemed to me that the higher the compression within the cylinder, the more the valve would be forced to stay closed.

[AL P]

Boost can blow the intake valve open...if the spring is weak enough and the boost is high enough...

[93LXHORSE]

Ok I get it now. The boost pressure is always sitting on top of each intake valve just politely waiting for the valve to open up and let some pressure in.

Weak spring = Mr. Boost just barges his way on in without being invited !

[STROKD]

Originally posted by turbostang
I guess it depends on how high you rev the motor vs. boost etc... It could be possible with off the shelf springs.. My hp peak is at 6,700, and I shift anywhere from 6,6-7K. My revlimiter is set at 7,000, and I only have about 9 psi at 6K and 15 at 6,700.

I never felt it do that before, but on my next few half track passes in eliminations it didn't do it at all, so like I said, not sure what the hell it was, maybe the blower belt spun on the pullies and it felt like it was missing since it goes rich with lost boost.:( :confused:

What is a good valve spring to go with? I only have a .545 lift Renegade style cam, nothing huge lift like.

AL P, I think I have hit the 7K limiter maybe 10 times since the motor was built... usually in the burn out box.:o

[NoSlix]

93LXHorse: more importantly, boost acts against the spring on the intake valve and effectively lowers it's spring pressure. This can allow you to have valve float before you would with the same spring pressure on a normally aspirated or nitrous motor.

[Andrew]

Hrm... 16 psi * pi * (2.02 inches/2)^2 = 51 pounds of force on the valve (yes, I ignored the area of the valve which is taken up by the stem as well as assumed that the valve surface is perfectly flat)...

This would tend to decrease the ideal on seat pressure from 150 pounds to 99 pounds, correct?

Originally posted by NoSlix
93LXHorse: more importantly, boost acts against the spring on the intake valve and effectively lowers it's spring pressure. This can allow you to have valve float before you would with the same spring pressure on a normally aspirated or nitrous motor.

[TRAXX]

Originally posted by Andrew
Hrm... 16 psi * pi * (2.02 inches/2)^2 = 51 pounds of force on the valve (yes, I ignored the area of the valve which is taken up by the stem as well as assumed that the valve surface is perfectly flat)...

This would tend to decrease the ideal on seat pressure from 150 pounds to 99 pounds, correct?


Dang it Andrew....I was about to bust out my TI-85 before I saw this:o

But I think that last statement is backwords (if I am hearing you correctly)

I would say what ever is the ideal on seat pressure is for your motor in a non forced induction application (I have no clue what that would be) you would need to up it by about 50 lbs to counteract the effect of 16 psi on the backside of the valve.

[Andrew]

I think we're on the same page... I'm saying that the spring needs to be ~50 pounds on seat pressure higher to counteract the boost, or that whatever spring you use has an effective 50 pounds less on seat pressure.

I just worded it poorly! lol

Originally posted by TRAXX
Dang it Andrew....I was about to bust out my TI-85 before I saw this:o

But I think that last statement is backwords (if I am hearing you correctly)

I would say what ever is the ideal on seat pressure is for your motor in a non forced induction application (I have no clue what that would be) you would need to up it by about 50 lbs to counteract the effect of 16 psi on the backside of the valve.

[Boost Addict]

Originally posted by Andrew
Hrm... 16 psi * pi * (2.02 inches/2)^2 = 51 pounds of force on the valve (yes, I ignored the area of the valve which is taken up by the stem as well as assumed that the valve surface is perfectly flat)...

This would tend to decrease the ideal on seat pressure from 150 pounds to 99 pounds, correct?

Your on the right track...but from an engineering standpoint we're ignoring alot of factors in that calculation. Namely, dynamic cylinder pressures during the four cycles. Assuming static conditions, your calc. is correct. Once we start entering the cycles you're going to see conditions that will make that 99lb somewhere near the low side (on both the ex. and int. valve). I think the real problem with the low spring pressure is going to be with the intake stroke for both valves, but especially for the ex. valve (i.e. the ex. valve being somewhat open during the intake stroke). Exhaust gases mixed in with the A:F mixture will result in the misfire condition you're experiencing.

Did you get a chance to check anymore of the valves?

[TRAXX]

Originally posted by Andrew
or that whatever spring you use has an effective 50 pounds less on seat pressure.

I just worded it poorly! lol


OK that makes more sense :)

[Andrew]

That makes sense... the 16 psi that the manifold sees is more of an "average" measurement. At each individual valve that pressure is going to vary depending on what is happening around it. Also I would think there would be a pressure drop when the valve opens as well.

I took the one that measured 120# off and am in the process of trying to find a machine shop that can measure the 1.800" height spring pressure. I went to two before work and neither could do it. Once I know that I know how far off the tool I'm using is and I can make reliable measurements on the rest of the springs.

The only thing that bugs me is that I never had this problem with the blower and I was seeing 21 psi manifold pressures...

Originally posted by Boost Addict
Your on the right track...but from an engineering standpoint we're ignoring alot of factors in that calculation. Namely, dynamic cylinder pressures during the four cycles. Assuming static conditions, your calc. is correct. Once we start entering the cycles you're going to see conditions that will make that 99lb somewhere near the median (on both the ex. and int. valve). I think the real problem with the low spring pressure is going to be with the intake stroke for both valves, but especially for the ex. valve (i.e. the ex. valve being somewhat open during the intake stroke). Exhaust gases mixed in with the A:F mixture will result in the misfire condition you're experiencing.

Did you get a chance to check anymore of the valves?

[Boost Addict]

Andrew,

Your static calculation is actually backwards. You should add the 150 lbs. and 51 lbs. Effectively, you compressing the spring with the boost pressure and increasing the seat pressure.

[Unseen]

Originally posted by Boost Addict
Andrew,

Your static calculation is actually backwards. You should add the 150 lbs. and 51 lbs. Effectively, you compressing the spring with the boost pressure and increasing the seat pressure.

The extension of the spring causes seat pressure, not the compression.

[Andrew]

I guess I forgot that sum of forces = 0 thing.... lol

that's assuming that the valve doesn't move as a result of the pressure, of course.

So how does that affect dynamic operation and valve bounce after you return to the base circle (what I would assume is happening if the valvesprings are weak)?

Originally posted by Boost Addict
Andrew,

Your static calculation is actually backwards. You should add the 150 lbs. and 51 lbs. Effectively, you compressing the spring with the boost pressure and increasing the seat pressure.

[Boost Addict]

Originally posted by Andrew
I guess I forgot that sum of forces = 0 thing.... lol

that's assuming that the valve doesn't move as a result of the pressure, of course.

So how does that affect dynamic operation and valve bounce after you return to the base circle (what I would assume is happening if the valvesprings are weak)?


Sum of forces = 0 is for civil engineers....they build targets

Sum of forces = M*A for mech. engineers....we build weapons. LOL


Sorry. One of my friends went to an engine school a few weeks ago. With proper seat pressure you wouldn't believe the bounce and 'jump' the lifter sees at the cam lobe....predominantly over the top. However, in higher lift applications (.580 and greater), the lifter would 'crash' into the lobe closer and closer to the base circle of the lobe. It was amazing.

So basically, if it is that bad with proper seat pressures....you can imagine how bad it is with seat pressures that are too low.

[Andrew]

I took one course in statics and one course in dynamics freshman year of college... it's been awhile!

What exactly are you saying about 'crash'? This is the point that the lifter contacts the cam if it's been launched off of the lobe? Did he see a lot of rebound off of the cam after it contacted it? FWIW my valve lift is .576".

Originally posted by Boost Addict
Sum of forces = 0 is for civil engineers....they build targets

Sum of forces = M*A for mech. engineers....we build weapons. LOL


Sorry. One of my friends went to an engine school a few weeks ago. With proper seat pressure you wouldn't believe the bounce and 'jump' the lifter sees at the cam lobe....predominantly over the top. However, in higher lift applications (.580 and greater), the lifter would 'crash' into the lobe closer and closer to the base circle of the lobe. It was amazing.

So basically, if it is that bad with proper seat pressures....you can imagine how bad it is with seat pressures that are too low.

[Boost Addict]

I have chosen to forget statics and dynamics....very painful memories. lol

Yes, 'crash' means the point that the lifter comes back in contact with the cam lobe. I don't know how much rebound there is once the lifter is back in contact with the lobe, but common sense says there will be at least some, the weaker the valve spring the worse this phenomenon would be I'm sure.

I was talking to Shane earlier about this and he brought up a good point. You might have a lifter issue as well. You've wrung that thing pretty tight and the Renegade guys are changing their lifters every two events, much more often than even the valve springs. We both think you need to go solid or at least freshen up the valve train. Either one will surely cure or at least help the problem. What lifters are in the car now?

[Andrew]

I've got stock replacement lifters. They've been on the car for quite a while. I've turned 7000 rpm max with them. I think I reused them from my old 302, although those were replaced 3 years ago or so.

Originally posted by Boost Addict
I have chosen to forget statics and dynamics....very painful memories. lol

Yes, 'crash' means the point that the lifter comes back in contact with the cam lobe. I don't know how much rebound there is once the lifter is back in contact with the lobe, but common sense says there will be at least some, the weaker the valve spring the worse this phenomenon would be I'm sure.

I was talking to Shane earlier about this and he brought up a good point. You might have a lifter issue as well. You've wrung that thing pretty tight and the Renegade guys are changing their lifters every two events, much more often than even the valve springs. We both think you need to go solid or at least freshen up the valve train. Either one will surely cure or at least help the problem. What lifters are in the car now?

[SNEAKY]

main question, wht was it fine before with the blower?
it was making 21psi before and revving just fine.
now it is only making 15psi and having problems.

[Boost Addict]

Definitely time for another replacement if you stay hyd. cam.

You're going fast enough now that you're going to be going through parts like that quite a bit quicker than normal. Did Anderson also tell you that the Renegade guys are using 3/8" pushrods instead of the usual 5/16"? Same engine school demonstrated 1/4" deflection on a hyd. roller setup in the pushrod alone. Translate that to lift-loss and it's absolutely scary!

It will be interesting to see what all the springs come back with.

[NoSlix]

One thing most people don't know is that the lifter leaves the cam lobe as it goes over the top on almost every cam combo you'll ever find. Even with correct spring pressure. How much it leaves the lobe is the big difference between hero and zero, though. If you don't believe me, find someone with a copy of a high speed film slowed down of the valvetrain in an engine. That's what Tony is speaking of in his post above.

As Tony said, Renegade racers that are turning 7500rpm are changing those stock lifters out after about 25-30 passes. You can modify the stock ones to work better in a motor such as yours since you don't have any rules that say they have to be bone stock. I'd highly recommend doing that if you're going to stay with the hydraulic roller. It can do nothing but help.

[Boost Addict]

Originally posted by SNEAKY
main question, wht was it fine before with the blower?
it was making 21psi before and revving just fine.
now it is only making 15psi and having problems.

That's a good question...I would at least guess that it has something to do with the engine producing a lot more torque at lower boost levels and rpm's. More torque equals more stress on all components...valvetrain included. This thing is going to have a lot more area under the curve and it may be enough that a weak spot has been found.

Didn't you say the car sat for some time during the 'change'?

[NoSlix]

Sneaky: Just goes to show you that 1 psi of manifold pressure out of one compressor is not the same as 1psi of manifold pressure from another compressor.

[SNEAKY]

Originally posted by Boost Addict
That's a good question...I would at least guess that it has something to do with the engine producing a lot more torque at lower boost levels and rpm's. More torque equals more stress on all components...valvetrain included. This thing is going to have a lot more area under the curve and it may be enough that a weak spot has been found.

Didn't you say the car sat for some time during the 'change'? two months i believe.
does more torque effect even the valve train?

[Andrew]

If I change it out I'm going solid...

What material were those pushrods made of?

The thing that bothers me is that with the blower I had zero problems running higher boost levels. I put the turbo, swap the 6AL and TFI blaster coil for a programmable digital 7 and HVC2 coil, and dumped the EPEC for a FAST with a crank trigger setup. I wonder if any of these other changes would cause this?

Originally posted by Boost Addict
Definitely time for another replacement if you stay hyd. cam.

You're going fast enough now that you're going to be going through parts like that quite a bit quicker than normal. Did Anderson also tell you that the Renegade guys are using 3/8" pushrods instead of the usual 5/16"? Same engine school demonstrated 1/4" deflection on a hyd. roller setup in the pushrod alone. Translate that to lift-loss and it's absolutely scary!

It will be interesting to see what all the springs come back with.

[SNEAKY]

Originally posted by NoSlix
Sneaky: Just goes to show you that 1 psi of manifold pressure out of one compressor is not the same as 1psi of manifold pressure from another compressor. even if on both set up, it was measured after the igloo?

i just believe that it is something else. possible something to do with the MSD/FAST talking to each other.

[Boost Addict]

I wouldn't think any of those changes would cause your problem. But a check of everything is definitely in order.

Sneaky,

Remember you're talking peak numbers. That YS probably made peak 21 psi...but that turbo is making 15 psi across the board. I haven't seen the graphs or anything, but it's possible he's encountering problems at an rpm where he actually had less boost than with the YS. Just a guess.

Andrew,

Just call up Cammotion and get a solid on order. Put some stout valve springs on it and at least you'll have no doubt about it being a contributing factor after that. Of course, then you'll end up like me and just swap everything out. lol

[Boost Addict]

Originally posted by SNEAKY
even if on both set up, it was measured after the igloo?

i just believe that it is something else. possible something to do with the MSD/FAST talking to each other.

Well, a simple swap back to the 6AL might confirm that.

[SNEAKY]

Originally posted by Boost Addict
Well, a simple swap back to the 6AL might confirm that. not possible

[Andrew]

How about this one? :D

RECOMMENDATION
Grind Number R2481-2391-14+4
Duration (intake/exaust) 249/242
Lift (intake/exaust) .654/.648
Lobe Center Separation 114
Intake Centerline 110
Comments LASH .024 HOT INT, & EXH. PRICE 290.00 + SHIPPING


Originally posted by Boost Addict
I wouldn't think any of those changes would cause your problem. But a check of everything is definitely in order.

Sneaky,

Remember you're talking peak numbers. That YS probably made peak 21 psi...but that turbo is making 15 psi across the board. I haven't seen the graphs or anything, but it's possible he's encountering problems at an rpm where he actually had less boost than with the YS. Just a guess.

Andrew,

Just call up Cammotion and get a solid on order. Put some stout valve springs on it and at least you'll have no doubt about it being a contributing factor after that. Of course, then you'll end up like me and just swap everything out. lol

[Andrew]

My current cam is 232/240 .576"/.576" on a 112 LSA. The gross duration is 299/307. I don't know what the intake centerline is off the top of my head...

[Boost Addict]

Damn, that is aggressive. My new solid is only .605 with 244/239 (app.). The lobe sep. and CL are right on with mine though.

Do you drive it on the street at all? I do, quite a bit actually. I just couldn't live with that much lift and duration. A turbo car doesn't really need a large lift number, but obviously cammotion is going to know more than me.

[Andrew]

I don't drive on the street too much... I'd get into trouble if I did! :D

Originally posted by Boost Addict
Damn, that is aggressive. My new solid is only .605 with 244/239 (app.). The lobe sep. and CL are right on with mine though.

Do you drive it on the street at all? I do, quite a bit actually. I just couldn't live with that much lift and duration. A turbo car doesn't really need a large lift number, but obviously cammotion is going to know more than me.

[AL P]

Just make sure and try to eliminate the Digital 7 and the coil as the source of the problem before changing out the whole valvetrain.

[turbostang]

It is just so hard to believe that the valve train "went bad" or just doesn't work after switching to a turbo .... but knowing that you did change all of the other stuff at the same time.. it just seems reallllly odd that it is NOT electrical.. Especially since removing that much fuel (by way of the fast) made the car go from 6.9's to 6.2's.........Now that I think about it.. it seems more electrical/ignition related. :confused: :confused: :confused:

[Andrew]

I plan on making some changes this week and bringing the car back out to the track this weekend to test....

Originally posted by turbostang
It is just so hard to believe that the valve train "went bad" or just doesn't work after switching to a turbo .... but knowing that you did change all of the other stuff at the same time.. it just seems reallllly odd that it is NOT electrical.. Especially since removing that much fuel (by way of the fast) made the car go from 6.9's to 6.2's.........Now that I think about it.. it seems more electrical/ignition related. :confused: :confused: :confused:

[turbostang]

Originally posted by Andrew
I plan on making some changes this week and bringing the car back out to the track this weekend to test....

Did the a/f look good through the last 6.1x pass? I did not get to see that one.. but I did see the others.. you couldn't harldy hear the miss when you stood behind the car and it went away..but you could hear it good when you were at half track and the car was coming to you... :eek:

[JamesB]

you could use my 7al and coil if needed, to eliminate the ignition

[NoSlix]

There ya go! I'd send ya mine but I need it this week.

[Andrew]

I just got back from the machine shop. The valvespring in question checked out at 145 pounds at 1.800".

[AL P]

Originally posted by Andrew
I just got back from the machine shop. The valvespring in question checked out at 145 pounds at 1.800".

Now you need to verify your installed height.

[Andrew]

Originally posted by AL P
Now you need to verify your installed height.

Yeah, I'll need to dig up a height gauge from somewhere....

[Mach1Marauder]

It just hit me what your problem is Andrew!!!!!!!!!!
Your damn fuel pump is so damn loud that your computer can't think straight!!!!!!!!! :D :D :D

[Andrew]

LOL!

I was redoing some of my wiring yesterday and I noticed that the wires from the ignition to the coil run RIGHT next to the alternator output for probably 3 feet or so... I know that the alternator output is somewhat noisy. Is the noise bad enough that it could cause a misfire from electrical noise coupling to the coil input?

Originally posted by Mach1Marauder
It just hit me what your problem is Andrew!!!!!!!!!!
Your damn fuel pump is so damn loud that your computer can't think straight!!!!!!!!! :D :D :D

[Mach1Marauder]

Originally posted by Andrew
LOL!

I was redoing some of my wiring yesterday and I noticed that the wires from the ignition to the coil run RIGHT next to the alternator output for probably 3 feet or so... I know that the alternator output is somewhat noisy. Is the noise bad enough that it could cause a misfire from electrical noise coupling to the coil input?

Ahhhh.........It could, but prolly if it was running paralell to it..............that could induce current in those lines.........otherwise I doubt it.

[NoSlix]

I doubt it. Now if it were the crank trigger output to the fast that was next to the alternator feed, it's definitely a possibility.

[Andrew]

The crank trigger wiring runs between the thermostat housing and the alternator and goes back between the passenger's side valve cover and the intake manifold.

The reason I'm getting concerned about crosstalk is that I recently had a problem with the FAST datalogging some weird RPM changes (I could see this on the tach as well)... revving the car would cause something like this to happen: 5800... 6000.... 6200... 3200... 6300... 6400... 4300... 6500... etc.

This was repeatable and happened on three consecutive runs.

I noticed that the wires from the igition box to the coil ran close to the points wire from the FAST to the ignition box. I rerouted the wires to put the ignition to coil wires away from the points wire and the problems went away.

Of note is that the ignition to coil wires ran next to the WBO2 wires for a significant distance (3 feet or so) inside the passenger side fender. I relocated that last night to put the WBO2 harness next to the crank trigger harness to try to alleviate noise coupling.

Originally posted by NoSlix
I doubt it. Now if it were the crank trigger output to the fast that was next to the alternator feed, it's definitely a possibility.

[NoSlix]

See if you can find some shielded wire. MSD makes a wire specifically for coils. You can also find something similar at most of the electronic supply stores.

[aggie97]

Why is it that the ONLY time you have problems with your car it is electrical? Aren't you an electrical engineer or something?;)

I hope this is all it is because this is an easy fix. Also, double check your grounds and it might be a good idea to add one to each side of the block. I was just reading the install instructions on my data logger and it said to ground the unit closest to the sensor I wanted the most accurate reading from. Grounding is very important........

[Andrew]

LOL!

I'll add another ground to the motor. Right now I only have the driver's side head grounded.

Originally posted by aggie97
Why is it that the ONLY time you have problems with your car it is electrical? Aren't you an electrical engineer or something?;)

I hope this is all it is because this is an easy fix. Also, double check your grounds and it might be a good idea to add one to each side of the block. I was just reading the install instructions on my data logger and it said to ground the unit closest to the sensor I wanted the most accurate reading from. Grounding is very important........

[93LXHORSE]

Check that ground wire I ran to the floorpan Andrew..... it could be suspect. I think I scratched the paint off with my fingernail or something....

[JamesB]

nice...

wouldn't the engine be grounded, via the solid motor mounts???:confused:

[SNEAKY]

Originally posted by JamesB
nice...

wouldn't the engine be grounded, via the solid motor mounts???:confused:


yes, but yuo are depending on a bunch of paint/rusted surfaces to cunduct.

Andrew, you got rid of all of the rats nest of wires, and now you are having wiring problems.


the irony.

[Andrew]

Isn't it though?

I get rid of the ignition setup that everyone says won't work (6AL, motorsport wires, Blaster TFI coil) for the bad boy stuff and I have ignition problems!

Originally posted by SNEAKY
yes, but yuo are depending on a bunch of paint/rusted surfaces to cunduct.

Andrew, you got rid of all of the rats nest of wires, and now you are having wiring problems.


the irony.