Dyno results from yesterday

[mcate]

The good: 263.5 max hp
The bad: 21.3 psi boost!
I guess Magnaporting the blower really works!
Definitely gonna take the 5% pulley off & put the stock one back on. Soon. Today, in fact!
Running a little too lean, too. 13.4 @ 3900 rpm to 12.8 @ 5280 rpm. I talked to Don O'Neill from the New Jersey T-Bird & Cougar Club yesterday & he highly recommends David Dalke. I'm working with him on trying to get together for a tuning session this summer. Looks like he's gonna be up in Jersey in either late June or early July doing the club up there. Don O'Neill says we can come up there too. The more, the merrier! I'll keep everyone filled in as I find out more.

[hellakornhaus]

What is the problem with running 21 PSI? Is that just TOO much for our engines? I ask... because I recently bought the MP supercharger, MP inlet plenum, installed injecters and the whole nine yards. I also have a 5% pulley on. Will I fall into trouble with the 5%, eventually? If so, why?

-Kornhaus

[mcate]

What is the problem with running 21 PSI? Is that just TOO much for our engines? I ask... because I recently bought the MP supercharger, MP inlet plenum, installed injecters and the whole nine yards. I also have a 5% pulley on. Will I fall into trouble with the 5%, eventually? If so, why?

-Kornhaus

From what I'm being told, that much boost can cause excessive heat, & pre-detonation or spark knock. That blows head gaskets. Having a double intercooler or the MP front mount IC helps cool the intake charge considerably, but it's still recommended to keep boost around 17 psi.

[Ira R.]

.......................posted in error.sorry.

[lube70]

Running that much boost is not the problem, the problem is the cams in these cars are NOT designed to let the volume of air out that fast. (On the 95 Mike has) This causes part of the old air charge (spent gases) to remain in the cylinder, causing high boost READINGS. Boost is a measure of pressure against the incoming air.

Some SC's (89's) for example have a better cam profile and allow for more air and not show such high boost pressures. Also, timing will affect this as does lean fuel mixtures. Lean mixtures are hotter and hot gases are larger in volume. This again, causes high boost readings.

Don't forget, a clogged cat will show the same results, not with HP readings like his though.


Air/fuel mixtures and timing are CRITICAL on these cars especially when modified. Just getting a chip from a manufacturer will not solve the problems arising from modding these motors. You need a true dyno tune and tune file to get max performance from your add-ons.

-----
What is the problem with running 21 PSI? Is that just TOO much for our engines? I ask... because I recently bought the MP supercharger, MP inlet plenum, installed injecters and the whole nine yards. I also have a 5% pulley on. Will I fall into trouble with the 5%, eventually? If so, why?

-Kornhaus

-------

The problem is that the cylinder temps will get so high that you will cause detenation and damage the engine or blow the gaskets (safety net). Keeping cylinder temps cool and fuel mixture at safe levels will prevent this from happening.

Without exhaust modifications, you WILL HAVE PROBLEMS!!!! With stock exhuast, the restrictions are enormous, nevermind adding much more air to the equation. To get air in, you must be able to get air out. Without exhaust mods (perferably manifolds back), you are running on borrowed time.


Don

[mcate]

Thanx for that input, Don. David wrote me today & we're going to wait until we can get together somewhere & do a proper tune. Let me know when you guys get it set up up there & I'll try to make it.
I took the 5% off today & put the stock one back on. I'm looking for a stock pulley from an 89-93 if anyone knows where one's at.

[007_SuperCoupe]

Don has a lot of good information there. But there are some other issues at play in '94 -'95 SC's. I'm not sure what they are, but something very similar happened to a buudy of mine. He's got a mildly modified '94 SC. He has full exhaust, 70mm TB, ported inlet plenum, home ported supercharger, 5% pulley, and a few other minor parts. Dave D. actually came here to NE a couple weeks ago for a dyno tune. That particular SC posed a lot of problems. Even with the exhaust he was still pulling over 20 lbs of boost. He was also fighting detonation all day long. We've been wracking our brains to figure out why the boost was as high as it was. We've measured the pulley and it slightly smaller than a 5%, but not more than 7%. He couldn't even get the SC close to a tune with a C&L MAF, so he ended up going back to the stock one. His intake temps were 60* higher than mine, but I'm not sure that makes up for the 7lbs of boost that he easily had over me. (Same blower, same porting almost and same pulley)

Could the cam profile alone cause this much difference in boost readings?

He's going to be getting a better IC in the very near future, but I still don't think that is going to get his boost down enough.

I don't want to highjack this thread, but it appears that mcate is suffering from a very similar problem. Dave D's tune did not change the boost at all. In fact, to keep the car safe, he had to put the rev limiter very low...around 5k if I remember correctly. And boost is still at 20 psi.

Any additional thoughts?

[mcate]

Don has a lot of good information there. But there are some other issues at play in '94 -'95 SC's. I'm not sure what they are, but something very similar happened to a buudy of mine. He's got a mildly modified '94 SC. He has full exhaust, 70mm TB, ported inlet plenum, home ported supercharger, 5% pulley, and a few other minor parts. Dave D. actually came here to NE a couple weeks ago for a dyno tune. That particular SC posed a lot of problems. Even with the exhaust he was still pulling over 20 lbs of boost. He was also fighting detonation all day long. We've been wracking our brains to figure out why the boost was as high as it was. We've measured the pulley and it slightly smaller than a 5%, but not more than 7%. He couldn't even get the SC close to a tune with a C&L MAF, so he ended up going back to the stock one. His intake temps were 60* higher than mine, but I'm not sure that makes up for the 7lbs of boost that he easily had over me. (Same blower, same porting almost and same pulley)

Could the cam profile alone cause this much difference in boost readings?

He's going to be getting a better IC in the very near future, but I still don't think that is going to get his boost down enough.

I don't want to highjack this thread, but it appears that mcate is suffering from a very similar problem. Dave D's tune did not change the boost at all. In fact, to keep the car safe, he had to put the rev limiter very low...around 5k if I remember correctly. And boost is still at 20 psi.

Any additional thoughts?

No worries here about hijacking the thread, Sam. All inputs are greatly appreciated. I haven't heard any detonation in my car, at least not audible. I've had lots of cars that pinged through the years, so I know what it sounds like. I also have a double intercooler & fan that should help. And I put my old stock blower pulley on this afternoon. I think the stock 94-95 pulleys were the largest, so my boost ought to drop by 3 lbs or so. I nailed it today & it still pegged the gauge, but not nearly as quickly as before.

[lube70]

Don has a lot of good information there. But there are some other issues at play in '94 -'95 SC's. I'm not sure what they are, but something very similar happened to a buudy of mine. He's got a mildly modified '94 SC. He has full exhaust, 70mm TB, ported inlet plenum, home ported supercharger, 5% pulley, and a few other minor parts. Dave D. actually came here to NE a couple weeks ago for a dyno tune. That particular SC posed a lot of problems. Even with the exhaust he was still pulling over 20 lbs of boost. He was also fighting detonation all day long. We've been wracking our brains to figure out why the boost was as high as it was. We've measured the pulley and it slightly smaller than a 5%, but not more than 7%. He couldn't even get the SC close to a tune with a C&L MAF, so he ended up going back to the stock one. His intake temps were 60* higher than mine, but I'm not sure that makes up for the 7lbs of boost that he easily had over me. (Same blower, same porting almost and same pulley)

Could the cam profile alone cause this much difference in boost readings?

He's going to be getting a better IC in the very near future, but I still don't think that is going to get his boost down enough.

I don't want to highjack this thread, but it appears that mcate is suffering from a very similar problem. Dave D's tune did not change the boost at all. In fact, to keep the car safe, he had to put the rev limiter very low...around 5k if I remember correctly. And boost is still at 20 psi.

Any additional thoughts?

I don't want you hijacking MY THREAD!!!!

ONLY KIDDING!!!!!

One thing here is ALL input is appreicated!!!!!!!!


You are right, 94-95's are different in the fact that they have a newer processor (bordering on the EEC-V or OBD-I. Also, sounds like your friend had other SERIOUS problems. Sometimes, coolant temps are too high and that will cause serious problems. Also, Intake charge temps are critical in tuning. If the charges are too high, it will cause major problems. Did he have a cam change???? If not, sounds like the coolant (radiator problems) or IC (again, coolant issues, keeping underhood temps down) temps were the problem. Answering your question, the cam CAN CAUSE THIS PROBLEM!!! The cam is the valve opener and if the valves are not opening enough to get the air out, you HAVE A PROBLEM!!! Not serious, as the engine's cam profile was not designed for this much modification.

Also, some autos don't tolerate timing. If the car has higher mileage or a lot of deposits on the valves or pistons, this will cause "hot spots" that will ignite the mixture prematurely and cause mojor problems.

Another classic problem with 94's and 95's is that the teflon coating from the rotors clogs the intercooler and causes higher than normal air charge temps. 60* is a lot of temp increase over any other car there. Sounds like a definite problem with air cooling or engine cooling.


Ira.....detonation is not pinging....A valve ping is when the valves "chatter" or move around in their guide and cause noise. The detonation sounds like a knock or "bang" in the motor. By the time you hear it, it's already too late!!!!

The idea is to PREVENT this from happening so that to guard the motor from damage.

I hope this thread continues and grows. Many more people need to read about how this works. Knowledge is POWER!!!!



Don

[007_SuperCoupe]

Also, sounds like your friend had other SERIOUS problems. Sometimes, coolant temps are too high and that will cause serious problems.

Also, Intake charge temps are critical in tuning. If the charges are too high, it will cause major problems. Did he have a cam change???? If not, sounds like the coolant (radiator problems) or IC (again, coolant issues, keeping underhood temps down) temps were the problem. Answering your question, the cam CAN CAUSE THIS PROBLEM!!!

Also, some autos don't tolerate timing. If the car has higher mileage or a lot of deposits on the valves or pistons, this will cause "hot spots" that will ignite the mixture prematurely and cause mojor problems.

Another classic problem with 94's and 95's is that the teflon coating from the rotors clogs the intercooler and causes higher than normal air charge temps. 60* is a lot of temp increase over any other car there. Sounds like a definite problem with air cooling or engine cooling.


Don

The engine coolant temps did rise, but in proportion to the intake temps. His intake temps were virtually off the charts...around 150* at the end of his runs. That's compared to my mid 90s at the end of my runs. I do have a custom 2x IC with fan, and he's running a stock IC for now. We've identified that as the first step to correcting the high temps. But that alone can't account for nearly 7lbs of boost.

His SC is an auto with over 100k. I'll look into some deposit cleaning agents there.

It's not the teflon as we had his sc apart less than a month ago. His teflon is in much better shape than the teflon on my sc. Virtually no chipping at all. His sc underwent a rebuild and porting as well. We did not touch the outlet though like I did on mine. I'm thinking that if we open that up just a little, that will further reduce temps. But not by a whole lot.

We are more concerned with the high boost levels though as this can cause HG failure on stock gaskets. He's looking at a rebuild next summer, but we'd like to be able to lower the boost a bit without changing pullies out. He's got a good tune right now, with a dead on 12:1 af ratio, but the boost is just too high for comfort on an otherwise stock engine. Maybe some BG 44K will clean out some of those deposits and increase airflow just a tad...

[nickleman60]

hey mike,bolt on a nitrous kit and that'll lower the air temp alot plus add a few more ponies