fuel pressure

[Joeld]

your statement is correct
with vacuum line and boost i get no higher than idle with no vacuum line

 

[we4Mateo]

You still haven't proven that your fuel supply is inadequate. 93 octane is 93 octane. Which is heavier,a lb of feathers or a lb of bricks. The number 93 tells you how resistant the fuel is to autoignition. It has the same resistance as it did years ago. How do I know? Because of the number 93.

I disagree somewhat. The rating is the average of manufacturer rating and testing. Plenty of details about this out there, but 93 even 10 years ago was formulated very differently than 93 today so 25 years ago was WAY different, no mtbe now, more ethanol content now, etc. There is still plenty of need for a modern chip, even without the timing tables, in that Bob and Eric can make these cars run better, without unnecessary ecm functions that the manufacturers are required to put in, while still achieving good fuel economy, better than stock idle, and overall better driveability from 25 years of electronic sfi management programming skills and tricks. Heck, a translator pro and stock ecm would blow the minds of the factory engineers back in the 80s.

 

[we4Mateo]

A 138 blm isn't bad either. Guys go crazy over that 128 but anything within 10 is acceptable. It'll change with different temps. If it stays within 10, 118-138, at cruise as well, don't worry about it. Still look into your wot psi though. I think the pump, hotwire, and regulator will solve that and you'll be reliably off to the races, so to speak.

 

[Ttype6]

I disagree somewhat. The rating is the average of manufacturer rating and testing. Plenty of details about this out there, but 93 even 10 years ago was formulated very differently than 93 today so 25 years ago was WAY different, no mtbe now, more ethanol content now, etc. There is still plenty of need for a modern chip, even without the timing tables, in that Bob and Eric can make these cars run better, without unnecessary ecm functions that the manufacturers are required to put in, while still achieving good fuel economy, better than stock idle, and overall better driveability from 25 years of electronic sfi management programming skills and tricks. Heck, a translator pro and stock ecm would blow the minds of the factory engineers back in the 80s.

Do you think Joel should be able to run 15 lbs of boost with today's 93 octane on the stock chip..

 

[we4Mateo]

Do you think Joel should be able to run 15 lbs of boost with today's 93 octane on the stock chip..

No. He'd probably be safe but I highly doubt it'd be a knock-free tune no matter what you raised the fuel pressure to even with a new pump/hotwire. An adjustable regulator would just flood the motor if fuel pressure was raised too much over stock. I can't run 12psi of boost (stock TR boost) without knock with my stock chip on 91 octane and that was a few years back when gas had less ethanol.

 

[we4Mateo]

I think stock chips work well with a little alky. I have a buddy that finally put alky on his mostly stock car just as a safety measure against todays gas, and it's been working great for him and it barely uses any with the stockish tune. He does run a TT chip but stock pump and no hotwire!

 

[Ttype6]

I think stock chips work well with a little alky. I have a buddy that finally put alky on his mostly stock car just as a safety measure against todays gas, and it's been working great for him and it barely uses any with the stockish tune. He does run a TT chip but stock pump and no hotwire!

Are you saying that your friend was unable to run 17 lbs with a modern chip (low timing)?
When and how long did you run the stock chip? How much boost were you able to run with it?

 

[Ttype6]

I can't run 12psi of boost (stock TR boost) without knock with my stock chip on 91 octane and that was a few years back when gas had less ethanol.

Joel has 93 available.

 

[Joeld]

i should be clear in my numbers

without vacuum i am at 35 psi with vacuum under boost i am at 35-36 pounds

ttype has made it clear that i am gaining no psi with boost

i did not understand that once i am i am at one pound of boost i should ne building pressure of 35+ a pound for each pound of boost

i am gaining no psi of fuel with boost regardless of amount of boost i am only getting to where i was without vacuum

this will be a good case study of tackling one bit at a time

thanks guys
joel

 

[we4Mateo]

Joel has 93 available.

It doesn't matter. It's all the same crap gas. We're splitting hairs over 1psi of boost and the same difference in timing, which can't be adjusted on a stock chip. If he can run knock-free at 12psi, even after getting the fueling figured out, verified via scanmaster or any device reading the knock signal, then I'll let it go. What is your point anyway? I'm merely stating I've never seen a stock chipped car on any pump gas alone, even at 10psi and 93, run without knock. And this is why he should get a new chip; that's all I'm stating. Are you stating that you have seen stock chip cars running around on pump gas without knock at anything over 10psi of boost? I'll be impressed and leave it all alone if you tell me "yes" b/c getting rid of knock on a stock chip car usually requires raising the base fuel pressure so far that it runs pig rich at wot which isn't going to make any power. 10-12psi with low enough timing to run knock free on any pump gas makes a TR feel pretty good yet if it isn't too rich. Safe timing on 12psi is usually good to 15psi and with the fueling right, 15psi and "low" timing really makes a strong car and 15psi is easy to achieve, even on 91, with a modern chip. It's not so easy to achieve with the stock chip. I think others will agree that 15psi with low timing and no knock will be stronger than 12psi and marginally more timing and no knock at the same afr. He'll need a modern chip to achieve the safe 15psi tune and make the car feel at least as good as the stock chip at 12si and higher timing and no knock all else equal. GM figures a certain amount of knock is acceptable and that is burned into the stock chips through aggressive timing tables. I simply prefer to run my car knock free at 15psi and end up with more power than stock anyway, or at least the same.

Make sense? I'm glad to be wrong about stock chip cars not being able to run 10psi knock free on todays gas without being hog rich but that's my experience with them thus far with today's gas.

 

[we4Mateo]

Are you saying that your friend was unable to run 17 lbs with a modern chip (low timing)?
When and how long did you run the stock chip? How much boost were you able to run with it?

Even at 12psi, he needed a splash of race gas to make it knock free with the stock chip which he ran for at least 2 years when he got the GN 7 years ago. And this is a bone stock, low mile car. He also was not able to run 17psi, even with TT chip, without knock. We probably could have drastically dropped timing to run 17psi since the TT chip is adjustable. He likes 17psi since that's what his TTA made roughly and he liked the way that motor felt @ 17psi so he always shot for that. He's a timing junky too though so he decided on alky instead of just lowering the timing to where he could run 17psi.

 

[Ttype6]

Even at 12psi, he needed a splash of race gas to make it knock free with the stock chip which he ran for at least 2 years when he got the GN 7 years ago. And this is a bone stock, low mile car. He also was not able to run 17psi, even with TT chip, without knock. We probably could have drastically dropped timing to run 17psi since the TT chip is adjustable. He likes 17psi since that's what his TTA made roughly and he liked the way that motor felt @ 17psi so he always shot for that. He's a timing junky too though so he decided on alky instead of just lowering the timing to where he could run 17psi.

I'm guessing that since you mentioned 91 octane,you don't have 93 where you live. I'll also assume your friend doesn't have access to it. My original comment was that Joel should be able to run 17 lbs of boost with 93 octane. In 1989 my car was stock with an adjustable wastegate. The first thing I did was adjust it for 17 lbs of boost because I knew that the increased power,for a stock GN,provided by the aftermarket chips of the time came from the extra boost they created. This is still true today. It ran strong with no knock. It wasn't long before I purchased a Kenne-Bell chip which had the same fuel and spark map as the stocker. I've seen people post many times in this community that you want to stay away from the Kenne-Bell chips because they have too much timing. The extra performance,provided by the chip came from the 17lbs of boost it was burned to produce. My car didn't produce any more power with the new chip as I was already running 17 lbs. It ran strong at 17 psi with no spark retard. I ran this setup until 99. Since then,Ive always been able to and am still able,with my current set up,to run 17 psi with 93 octane and 18 degrees of spark advance. In my world the gasoline quality hasn't changed and time and time again I've seen people post these same capabilities in the turbo Buick community using 93 octane. Joel is going to be the next one to do this.

 

[we4Mateo]

I'm guessing that since you mentioned 91 octane,you don't have 93 where you live. I'll also assume your friend doesn't have access to it. My original comment was that Joel should be able to run 17 lbs of boost with 93 octane. In 1989 my car was stock with an adjustable wastegate. The first thing I did was adjust it for 17 lbs of boost because I knew that the increased power,for a stock GN,provided by the aftermarket chips of the time came from the extra boost they created. This is still true today. It ran strong with no knock. It wasn't long before I purchased a Kenne-Bell chip which had the same fuel and spark map as the stocker. I've seen people post many times in this community that you want to stay away from the Kenne-Bell chips because they have too much timing. The extra performance,provided by the chip came from the 17lbs of boost it was burned to produce. My car didn't produce any more power with the new chip as I was already running 17 lbs. It ran strong at 17 psi with no spark retard. I ran this setup until 99. Since then,Ive always been able to and am still able,with my current set up,to run 17 psi with 93 octane and 18 degrees of spark advance. In my world the gasoline quality hasn't changed and time and time again I've seen people post these same capabilities in the turbo Buick community using 93 octane. Joel is going to be the next one to do this.

There's more than 18 degrees timing in a stock chip...he will not run 17psi with it, even with 93. And if you believe gasoline quality hasn't changed, I'll have two of what you're having. Any yes, people do run up to 20psi on 93, but not with stock intercoolers. You're combo clearly does, and should, support more boost on pump gas than a stock turbo blowing through a stock intercooler. You're also still comparing your stock combo from 20 years ago to a stock combo's capabilities today and that doesn't compute. I want to hear your experience lately of running a stock car on pump gas only.

 

[we4Mateo]

I do agree with you that 93 is 93 octane but you do need to run a bit more of it due to the higher ethanol content. It has the same detonation resistance perhaps but not the same energy quotient and that needs to be considered when maxxing out the best afr.

 

[Joeld]

installing hotwire tonight, I should have new numbers later this evening or tomorrow am.
I'm learning a ton through the process and continue to be thankful to your guys approach of forcing me to understand, I'll never get it right otherwise. Your instwillingness for me to benefit from your trial and error is really something.
Thank you,
Joel

 

[we4Mateo]

installing hotwire tonight, I should have new numbers later this evening or tomorrow am.
I'm learning a ton through the process and continue to be thankful to your guys approach of forcing me to understand, I'll never get it right otherwise. Your instwillingness for me to benefit from your trial and error is really something.
Thank you,
Joel

You're going to have a great time figuring these cars out. The journey is the best part.

 

[Joeld]

OK, I installed the hotwire and VDO boost guage.
11-12 PSI of boost, WOT, 41 psi of fuel and knock. BL has dropped a bit to low 130's at idle.
Next will be the fuel regulator. If that does not work, then fuel pump.
Getting closer.
I will also get a different fuel guage to see if I see any difference there. Either way, still fighting knock, you guys have me hating knock and nothing short of no knock will do.
Thanks,
Joel

 

[Joeld]

The more reading I'm doing the more it looks like I just can't avoid replacing the fuel pump no matter how much I don't want to drop the tank. I ordered the fuel sender as I have a feeling mine is, well, old and if I'm going to be installing a fuel pump I mind-as-well replace the sending unit.
Amazing how much tinkering these cars require even if components have super low hours on them.
Joel

 

[87-WE2]

It's important to remember that even though there may be very few hours on the motor, the components are still 25 years old and subject to the effects of age. It took me a while to grasp that as well.

 

[Joeld]

I am preparing myself emotionally to drop the tank, some chocolate icecream for motivation and I'll have at it.
Joel