Can you tune a 1995 LT1 computer?
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From: Bowling Green
Can you tune a 1995 LT1 computer? My brother has a '95 Camaro z28 6 speed and just had to rebuild his motor. During the process, he decided to go with a high performance cam from comp cams. The only information I have on it is that it has a .51" lift and a 290 duration. Unfortunately, he did not use any supporting mods (springs, rockers, etc). Well, he knew he needed to get his computer tuned but every place he has called around said they can't do it because the '95 computer is OBD-I and the plug is OBD-II or something like that. Also, because of this issue, he's getting around 7-8 MPG. Is it possible to get his computer tuned? If so, how?
My brother has a '95 Camaro z28 6 speed and just had to rebuild his motor. During the process, he decided to go with a high performance cam from comp cams. The only information I have on it is that it has a .51" lift and a 290 duration. Unfortunately, he did not use any supporting mods (springs, rockers, etc). Well, he knew he needed to get his computer tuned but every place he has called around said they can't do it because the '95 computer is OBD-I and the plug is OBD-II or something like that. Also, because of this issue, he's getting around 7-8 MPG. Is it possible to get his computer tuned? If so, how?
Yes, it can be tuned. Also, and more importantly, if he put a larger cam in and did not upgrade the springs he will end up having a catastrophic failure.
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From: Crappy Stupid Liberal Washington state
This is the cable he'd need: http://www.aldlcable.com/sc/details.asp?item=aldlobd2u
And he needs to at lease upgrade his springs. He needs to park the car ASAP before he ends up dropping a valve into the engine. Running the car on a stock tune with an aftermarket cam can cause enough problems. Running the stock springs WAY out of their tolerances is a whole different ball game.
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Launching!
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From: Bowling Green
Yup, he can either send his PCM (or have one sent to him) to a mail order tuner. Or he can buy a cable and have a tune emailed to him.
This is the cable he'd need: http://www.aldlcable.com/sc/details.asp?item=aldlobd2u
And he needs to at lease upgrade his springs. He needs to park the car ASAP before he ends up dropping a valve into the engine. Running the car on a stock tune with an aftermarket cam can cause enough problems. Running the stock springs WAY out of their tolerances is a whole different ball game.
This is the cable he'd need: http://www.aldlcable.com/sc/details.asp?item=aldlobd2u
And he needs to at lease upgrade his springs. He needs to park the car ASAP before he ends up dropping a valve into the engine. Running the car on a stock tune with an aftermarket cam can cause enough problems. Running the stock springs WAY out of their tolerances is a whole different ball game.
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You seriously need to tell him to stop driving that car until that is all figured out. With 7 MPG he's probably washing out the cylinders this whole time with fuel, and eventually if he ever revs it high that thing is going to grenade. I can't believe people do this.
Anyway though.... You will hear that the 94-95 OBDI computer is sought after for tuning so yes it is possible like said.
Seriously a ticking time bomb on those springs, plus running so rich it's probably getting fuel past the rings watering down the oil. This is a situation that all could be avoided by getting info from people familiar with LTx engines, not SBCs. Your computer can easily be tuned, and with a set of springs that can handle the lift, you will see much better performance and better fuel mileage. What compression ratio did you use on the rebuild? What is your exhaust setup?
*edit*. Just realized your .51 lift 290 duration cam is the 306!!!!!! That WAY too big for stock springs!!! Coil bind on stock springs is .48, I can't believe nothing has broken yet. You need something good to around .6 to be safe.
*edit*. Just realized your .51 lift 290 duration cam is the 306!!!!!! That WAY too big for stock springs!!! Coil bind on stock springs is .48, I can't believe nothing has broken yet. You need something good to around .6 to be safe.
Last edited by bufmatmuslepants; Aug 21, 2013 at 07:37 AM.
I can't believe people do stuff like this. This is why LT1s get such a bad rep...CC306 on stock springs/heads 
.
He has way bigger things to worry about then a tune. I don't know any tuner who would even risk tuning that thing, it will probably grenade on the dyno. No way stock springs are handling multiple WOT runs with a 306. Even if the springs don't physically break, there is no way they can control the valve at the RPM a stock head 306 car will want to spin at.
.He has way bigger things to worry about then a tune. I don't know any tuner who would even risk tuning that thing, it will probably grenade on the dyno. No way stock springs are handling multiple WOT runs with a 306. Even if the springs don't physically break, there is no way they can control the valve at the RPM a stock head 306 car will want to spin at.
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I think the only thing that's saving him is the fact his cam's lift is prolly specd with 1.6rr. And by him using STOCK springs and roller rockers his lift is prolly right at .480 lift. SMH if money is an issuse I heard that the Alex springs are a good bang for buck..
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Staging Lane
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From: Virginia Beach, VA
...You seriously need to tell him to stop driving that car until that is all figured out. With 7 MPG he's probably washing out the cylinders this whole time with fuel, and eventually if he ever revs it high that thing is going to grenade. I can't believe people do this...
Bottom line, help you brother sign up for this forum and get involved. He'll save a ton of time and money while ending up with a better understanding of what it takes to do the mods he wants.
Good Luck!
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From: Nebraska
This is all too common when a bunch of guys sit around BSing about what they "can" or "will" do to their car/engine to make more HP. The advice given out at these bull sessions is usually wrong! That's why forums like this one are so popular. It's rare that you'll find a mod that hasn't been done before by someone on the forum. Plus, if you do have an individual giving out bad advice, the forum will quickly come down on him to prevent someone from taking drivel for gospel and possibly ruining an engine because of it.
Bottom line, help you brother sign up for this forum and get involved. He'll save a ton of time and money while ending up with a better understanding of what it takes to do the mods he wants.
Good Luck!
Bottom line, help you brother sign up for this forum and get involved. He'll save a ton of time and money while ending up with a better understanding of what it takes to do the mods he wants.
Good Luck!
Thread Starter
Launching!
Joined: Nov 2012
Posts: 206
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From: Bowling Green
Seriously a ticking time bomb on those springs, plus running so rich it's probably getting fuel past the rings watering down the oil. This is a situation that all could be avoided by getting info from people familiar with LTx engines, not SBCs. Your computer can easily be tuned, and with a set of springs that can handle the lift, you will see much better performance and better fuel mileage. What compression ratio did you use on the rebuild? What is your exhaust setup?
*edit*. Just realized your .51 lift 290 duration cam is the 306!!!!!! That WAY too big for stock springs!!! Coil bind on stock springs is .48, I can't believe nothing has broken yet. You need something good to around .6 to be safe.
*edit*. Just realized your .51 lift 290 duration cam is the 306!!!!!! That WAY too big for stock springs!!! Coil bind on stock springs is .48, I can't believe nothing has broken yet. You need something good to around .6 to be safe.
Also, are sure it's the cc306? I was doing some research and from what I found, the 306 specs are 229/245 510/540 on a 112 LSA
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Well, you're right about needing to get info from people "knowing about LTx's instead of SBCs." One of our friend's has been working on cars for years, (been doing a very good job, too) but his main knowledge is in the SBCs. My brother's LT1 was the first one he's ever worked on so naturally, I can see the confusion.
Also, are sure it's the cc306? I was doing some research and from what I found, the 306 specs are 229/245 510/540 on a 112 LSA
Also, are sure it's the cc306? I was doing some research and from what I found, the 306 specs are 229/245 510/540 on a 112 LSA
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From: Crappy Stupid Liberal Washington state
Well, the first problem he had was putting in a cam without even knowing what was going in the car.
How in the world is this car passing smog running this rich? Or is he driving it illegally?
How in the world is this car passing smog running this rich? Or is he driving it illegally?
I think if you really looked at it, 99% of the people on this board are driving illegally. Off road y pipes, deleted rear O2s, deleted egr etc, hell my car is registered in WV so I don't have to deal with MD emissions or inspection.
That can be true at a couple of levels. Illegal but registered is one thing.
Illegal and not registered is another. That is stupid. Your car is registered, O2 sims and tune allow a car with extra hp to be registered. I have cars getting 10-12 mpg with good tunes that will pass a sniff test so they are registered.
Running a high overlap cam with no tune won't pass any test particularly in a pre OBDII car as they all must be sniffed.
Illegal and not registered is another. That is stupid. Your car is registered, O2 sims and tune allow a car with extra hp to be registered. I have cars getting 10-12 mpg with good tunes that will pass a sniff test so they are registered.
Running a high overlap cam with no tune won't pass any test particularly in a pre OBDII car as they all must be sniffed.
OK, you are legal, which means you haven't done any test to see that you are spilling fuel out the car at a rate that at least doubles your operating costs and likely is washing down the cylinder walls and fuel doesn't lubricate nearly as well as oil.
Getting that car tuned is trivial but someone needs to log it and than tune it. Not doing so is slowly destroying it and your brothers pocketbook.
I presume you have a computer. Get a data cable along with one of the OBDI to OBDII connectors and buy at least logging software (I use TTS Datamaster) and than log it extensively and send that log to a mail order tuner. As it is not a chipped car you may than need to either buy something to load the tune (I use Tuner Cat as well as LT1Edit) or send your PCM out to the tuner to get the new tune loaded and at last you will have the car operating roughly within reasonable operating specs.
I suppose I would find out exactly what the cam is and than decide what other changes I would need to make to the valve train (if any) to support that cam.
Once that is done you should likely be back up in the 14-16 or over mpg range and in a couple of months will have recovered whatever costs you have incurred to get there.
Getting that car tuned is trivial but someone needs to log it and than tune it. Not doing so is slowly destroying it and your brothers pocketbook.
I presume you have a computer. Get a data cable along with one of the OBDI to OBDII connectors and buy at least logging software (I use TTS Datamaster) and than log it extensively and send that log to a mail order tuner. As it is not a chipped car you may than need to either buy something to load the tune (I use Tuner Cat as well as LT1Edit) or send your PCM out to the tuner to get the new tune loaded and at last you will have the car operating roughly within reasonable operating specs.
I suppose I would find out exactly what the cam is and than decide what other changes I would need to make to the valve train (if any) to support that cam.
Once that is done you should likely be back up in the 14-16 or over mpg range and in a couple of months will have recovered whatever costs you have incurred to get there.