Help me decide what to do with my 87 GN

[earlbrown]

I fixed the typo. I mean 50's to keep the diamater/tire height correct.

I have nothing against E85 (except the IRS fucked it up by forcing a 15% gasoline blend)... BUT, you're still learning these cars. That's just one tuning factor you don't need right now.

Until you have a SOLID foundation, both mechanical with the car and mental with you, don't overcomplicate things more than neessessary.

On your injectors, I didn't realize you still had original stockers.... Toss 'em and get a set of 60's and a mating chip. Yes, I know that sounds major but if your car had a carb and it was 30 years old, worn out, and dirty, would you tune around it?....

 

[1952ray]

I fixed the typo. I mean 50's to keep the diamater/tire height correct.

I have nothing against E85 (except the IRS fucked it up by forcing a 15% gasoline blend)... BUT, you're still learning these cars. That's just one tuning factor you don't need right now.

Until you have a SOLID foundation, both mechanical with the car and mental with you, don't overcomplicate things more than neessessary.

On your injectors, I didn't realize you still had original stockers.... Toss 'em and get a set of 60's and a mating chip. Yes, I know that sounds major but if your car had a carb and it was 30 years old, worn out, and dirty, would you tune around it?....

Good to see you back and talking sh t Earl. As always you are right on. But but but E85 is not going to be E85 in two or three years. Going to be a lot of crying Buick people. Watch what I'm telling you.

 

[ttribejr]

Yes I am new to the buick. but not to cars or efi tuning on NA, Nitrous and turbo applications. E85 is the sh1t. there is no denying it. Yes I have had alcohol injectoed turbo cars too. IMO a straight e85 car is easier to get right than a pump/alcohol car. That said I am not opposed to either option. I am personally not sure what I will go with.

I have a fuel issue. Might be lazy/dirty stock injectors. Or could be a new part i just installed:

Friday night I installed the walbro, new in-line fuel filter and Hotwire kit. Today I installed my Accufab FPR and gauge. You know I could not turn it down lower than 41 PSI. I set it 43 PSI w/o a vacuum signal, but still I thought 41 PSI was high for a lowest possible setting. This was according to a Marshal fluid filled Fuel pressure gauge. Is this normal or did I get a defective unit?

For the most part, I was 780-low 800s at WOT. But random low 700s and 3.x knock occured. So in other words, it was not consistent.

So this street chip says 16psi hand written on it. I have no boost gauge yet. Does that mean the chip should be controlling the wastegate solenoid to 16 psi? or does that mean the map covers up to 16 psi and I have to get a boost controller to set it there myself?

I like the car. Im not 100% positive this is the one I am going to invest a ton of money and time into. Im just feeling it out at this point. And I appreciate everybody's advice and comments.

 

[earlbrown]

With original injectors you need to stop thinking about the tune until you get those things out and replaced. They're just too old at this point. Tuning around original injectors is like tuning around a bad spark plug wire. It won't work and when you replace the wire you get to start over.


You might have a pinched return line. For only a 2PSI drop to be accurate you'd have to be idling at 4 inches of vacuum and I know that's not going on. Rail mount gauges are notoriously inaccurate but in the real world that doesn't matter. Not to mention liquid filled gauges are inaccurate by design if they are exposed to temp swings (which underhood gauges are).


On your chip, the handwritten 16PSI means it was burned to supply close to the exact amount of fuel for a 3.8 at WOT making 16PSI. Needless to say that's not an exact science so it's just a starting point and the owner tunes from there. If you run less than 16 you should be fat as hell and if you go way over 16 it should go lean.


Honestly, it sounds like you're relying on previous tuning results with other cars and that can bite you right in the ass with a quickness. A search on this board might find you 100 examples of that very thing. Keep in mind these cars have an engine make of a iron using 60's tech. GM slapped a turbo and an intercooler and some 'badass hi-tech 80's' electronics and made a BUNCH of power with only 3 spark per crankshaft rev... then 30 years later us idiots damn near double the power on a 'stock' street car... Pushing old tech that far requires due diligence. That means that EVERY weak link needs to addressed. A chain is only as strong as it's weakest link and when the Buick V6 loses a link it's both ugly and expensive. Riding around with 30 year old parts that are past their prime while flying blind with no boost gauge or data tools is asking for it. That is just a recipe for coming apart with a quickness. Just like any other car, when you start pushing the envelope the nuances and quirks appear. If you jump past one of those, you're in trouble. If you're lucky, you lost a head gasket and stuck with all the ''well while my heads are off, I might as well.....''s. If you're unlucky the crankshaft tookout your expansive transmission when the crank hit the road at speed.


I'm probably not going to mention this again, but get the car running right on a solid foundation, then go from there.

If you're one of the guys that has to start bolting 9sec parts on a compromised car first, I can help you there too....

....but your wallet won't like the results.

 

[Scarab]

Everyone has some good advice, I appreciate it.

I think, for now, I am going to hold onto the car for a while. I really like the car. I have dreams of a BBC 68 camaro, but i'd have to sell both my cars to get a decent one.

I had a blown 67 camaro that i traded my old GN for. Never should have done that.. The Grand National has so much more meaning than the Camaro.

 

[ttribejr]

im 90% sure im going to keep it and build it. I am a buy once, cry once type of guy. So I may go overboard on fuel system or turbo / converter. So i can still drive the car and build it as the money is available.

I am researching FAST vs powerlogger/wideband chip right now. Waiting on some of the vendors here to get back to me on my turbo/converter emails.