Removing the lpm/chip...

[DavidT]

How would the engine react?
What is its main purpose with the s/* setup? Is it to regulate aIR/FUEL MIX?

My s/* has some issues... I think it could be running too rich. SOMETIMES it runs SCARY fast, other times it seems almost stock. And lots of times it has a miss/hesitation... most common when hitting the throttle in the low end./
I know these symptoms coyuld be a number of things. I am contemplating having the chip reprogrammed, but how do I KNOW if thats the problem?
I'm thinking if I remove it and the miss goes away, then I found the problem.
Could I do permanent damage by removing it? If so, what would be the consequences?
(It piggybacks on the stock computer)

 

[whfla]

nothing will happen , just take off battery cable first ! ....it is probobly not your problem though !!

 

[masho95]

How would the engine react?
What is its main purpose with the s/* setup? Is it to regulate aIR/FUEL MIX?

My s/* has some issues... I think it could be running too rich. SOMETIMES it runs SCARY fast, other times it seems almost stock. And lots of times it has a miss/hesitation... most common when hitting the throttle in the low end./
I know these symptoms coyuld be a number of things. I am contemplating having the chip reprogrammed, but how do I KNOW if thats the problem?
I'm thinking if I remove it and the miss goes away, then I found the problem.
Could I do permanent damage by removing it? If so, what would be the consequences?
(It piggybacks on the stock computer)

I don't believe anything will happen if you run the car at idle without it. But when the SC kicks in you are asking for trouble, as it controls your fuel and other various things.

 

[Chris Benvie]

DO NOT REMOVE IT ON A SUPERCHARGED CAR!!!

Only remove it to clean or to ad a TWEECER, s/* tuner, or other tuner.


It is possible to ruin that car my removing the chip.

 

[Axianator]

Out of curiosity, David, what type/brand of chip do you have on there now?

 

[Chris Benvie]

SHOshop LPM burnt for the supercharger.


It was a SHOshop built car. Leave it to them to put the blower on a stock motor.

Not that I dislike SHOshop but from what I have heard, it doesn't surprise me.


Considering I called looking for a new set of pistons for a car that they built the motor for and was told that they didn't have the build # for the pistons (isn't it illegal to not save the paperwork of everysale within 7 years?) So i was told i had to buy the whole set for $1600. Called JE and was told $150/piston.

 

[Axianator]

Gotcha. Thanks, Chris.

Concerning the blower, I guess it's possible that the previous owner speicifed to Vadim and crew that he wanted the blower kit installed on his stock motor and Vadim went ahead and accomodated him? Doesn't sound like the SHO Shop, but I guess it's possible. In Vadim's defense, though, there's really nothing wrong with running a blower on a stock CR motor, so long as you're careful about how you go about it. Heck, I plan to do the same thing (blower on a stock block) to my ATX later on this year, provided things go well. Don't tell anyone, though, it's a secret...

As for the LPM, David, I have to side with Chris' advisement that you do not drive the car without it. The LPM is programmed to deliver fuel based on the larger MAF and injectors contained within your existing setup - going back to the factory program by removing the LPM means that the EEC will start delivering fuel based on the factory MAF curve and injector slopes. This could eventually cause a lean condition and you might end up with a SHO BOOM! :ruhroh:

 

[AutoSHO]

Your car most likely will not start or run without the chip in. Not only does it have a different MAF than stock, but it also has HUGE injectors.

Did you replace the ECT yet?

 

[Axianator]

Your car most likely will not start or run without the chip in. Not only does it have a different MAF than stock, but it also has HUGE injectors.

Is that not more or less what I just said?

 

[Chris Benvie]

Ahh supercharged SHO's who woulda thunked that I would know anything about them.


I am still learning, this is all a process. I just wanna drive the f'in thing.

 

[Axianator]

I just wanna drive the f'in thing.

LOL, I hear there's a line forming at your door for people wanting to take rides, Chris.

 

[DavidT]

Your car most likely will not start or run without the chip in. Not only does it have a different MAF than stock, but it also has HUGE injectors.

Did you replace the ECT yet?

yep.
As projectsho said... the only improvement I saw was... EASIER to start. That's it

 

[PanamaPat]

SHOshop LPM burnt for the supercharger.


It was a SHOshop built car. Leave it to them to put the blower on a stock motor.

There are quite a few stock SHO motors with blowers on them. If you don't get greedy (as most of us end up doing) with the boost, you can get away with stock motors very well. No doubt, running low compression pistons with more boost gives more power more safely, but its not a requirement.

Also, keep in mind that retaining the higher compression stock setup does give you more low end power before the boost builds, a small benefit, but one that helps with every day driveability.

 

[PanamaPat]

SHOshop LPM burnt for the supercharger.
Not that I dislike SHOshop but from what I have heard, it doesn't surprise me.

Considering I called looking for a new set of pistons for a car that they built the motor for and was told that they didn't have the build # for the pistons (isn't it illegal to not save the paperwork of everysale within 7 years?) So i was told i had to buy the whole set for $1600. Called JE and was told $150/piston.

I had a similar reaction when I saw the low compression pistons from SS where $1500. But keep in mind that the SS I think includes many other items in their low compression kit includingistons, Piston Pins and Retainer,
Chrome-Moly Rings, Connecting Rod Bearings, Main Bearings, Oil Pump, Gaskets and Seals. No doubt there is a markup by the SS, but its worth noting that the difference in price does bring parts you will probably need when you build a low compression motor.

 

[PanamaPat]

As for the LPM, David, I have to side with Chris' advisement that you do not drive the car without it. The LPM is programmed to deliver fuel based on the larger MAF and injectors contained within your existing setup - going back to the factory program by removing the LPM means that the EEC will start delivering fuel based on the factory MAF curve and injector slopes. This could eventually cause a lean condition and you might end up with a SHO BOOM! :ruhroh:

I agree with all the comments on running without the LPM.

In addition to the concerns about running lean from ECU being confused about the non stock MAF and fuel injectors, you have a really big issue regarding spark timing under boost. The stock SHO runs 35+ degrees of timing past 4k RPM. A boosted SHO runs with as little as 22 degrees of timing past 4k RPM (progressive decline as boost builds). Without the LPM, your back to stock timing and with that much timing - detonation and pistong ring land damage is likely (voice of experience).

In my case, I restored full timing with a modified LPM and had trusted that my water injection would control the detonation - mistaken assumption! No doubt the water injection did allow for running more timing, but not as much as I tried to run. The damage that resulted was two pistons with broken ring lands.

 

[Mike Kopstain]

SHOshop LPM burnt for the supercharger.


It was a SHOshop built car. Leave it to them to put the blower on a stock motor.

Not that I dislike SHOshop but from what I have heard, it doesn't surprise me.

Not quite. They did not build the car, but rather sold the kit to a Father/ son duo in Texas. IIRC the father passed on.

Pat's got the right idea with the water injection. Curiously Pat, what kind of mix were you running in the system.

If everyone wants to hear another of my IMNSHO quotes, I think it's close to foolish to be running the motors with this much boost and no intercooler, water injection, propane (If you're nuts ), or any other form of cooling charge. At 12 - 15 psi even on a low compression motor you're going to be running some degree of knock and to my recollection, there is no real time datalogging of knock retard on TwEECer or any other program for that matter, so that's even more reason to make sure that you've done it right the first go.

Looking around to other cars that are modded and un-naturally aspirated it will become readily apparent that few are running upwards of 12 - 15lbs with no intercooler. I think it was a trend started in the SHO community early on and was just followed. This is the exception, not the norm.

Of course, this is all my opinion and we all know what those are like.

 

[PanamaPat]

Not quite. They did not build the car, but rather sold the kit to a Father/ son duo in Texas. IIRC the father passed on.

Pat's got the right idea with the water injection. Curiously Pat, what kind of mix were you running in the system.

If everyone wants to hear another of my IMNSHO quotes, I think it's close to foolish to be running the motors with this much boost and no intercooler, water injection, propane (If you're nuts ), or any other form of cooling charge. At 12 - 15 psi even on a low compression motor you're going to be running some degree of knock and to my recollection, there is no real time datalogging of knock retard on TwEECer or any other program for that matter, so that's even more reason to make sure that you've done it right the first go.

Looking around to other cars that are modded and un-naturally aspirated it will become readily apparent that few are running upwards of 12 - 15lbs with no intercooler. I think it was a trend started in the SHO community early on and was just followed. This is the exception, not the norm.

Of course, this is all my opinion and we all know what those are like.

If I recall, Vadim recommended that the most he would run on a stock block was 9 PSI using conventional premium gas. And even then, you needed to watch your premium to make sure you did not run into a bad batch of gas. If you wanted to run 12 psi, he recommended that you run 101 or 105 octane all the time. If you wanted to run 15 psi, he suggested 115 octane.

I'm able to get away with running 15 psi with a stock motor mostly because of high altitude of denver having the effect of less compression ratio. Also, I run water injection and keep a very close eye on detonation with the aftermarket knock monitor, adjusting with extra fuel if detonation is getting to much.

I run windshield washer fluid which is around 30-40% methanol in the winter, and 100% distilled water during the summer. Water offers better detonation control than methanol.

It will be interesting to see if my SHO holds up to 15 psi of boost at sea level when I got to the convention this summer.