What race gas to get??

[Mera]

http://www.schmidtsgasngo.com/race-fuel-prices.html

I do not have a converter on my 87 all stock GN now. I do have the original prom and I will not be changing it because I want to keep my 87 GN more or less as close to original as possible. I can put the factory converter back on if I want to one day. Only take a few minutes. It only has 10,350 miles on it now. I've owned it for a year now but have never really spooled up the turbo much for fear of melting a piston top with detonation with today's not as good premium gas. So my idea is since I will probably only drive my GN at most 300-500 miles a summer (at best) is to keep mixing in some race fuel to bring up the octane so I can run it flat out occasionally and not worry about knock. This place shown above is fairly close to me. But look at all the race gas options! Which to use?? Maybe just that lowest cost leaded? Searching for higher octane fuel locally I find some saying that some higher octane gas just has some additives to raise the octane and is not really high quality high octane fuel. I want to think I should stay away from that type of higher octane fuel? I'm pretty sure all the race fuel sold at this Shell station is all high quality. They seem to be the biggest supplier in the Milwaukee area for race fuel. If I get the 110 octane I am thinking I can add maybe 2 1/2 gallons to each tank and that might be enough to insure I do not have any pre-detonation (knock) at the factory boost level?

Any opinions?

Thanks
Rodney

 

[dank GN]

I really don't get what you are trying to achieve ? You would drop the trans and change a converter but refuse to put a better chip in it ? If u want it stock then don't touch anything and throw in some premium 91 or 93 and drive it .

 

[Boost231]

Best thing you could do is change the chip. Www.turbotweak.com

Any octane fuel over pump will be good. Or straight 110 if your not driving it much

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[BRAD_PADGETT]

I have a stock 87 with the original GM chip. Cold start the engine would almost die. Rough idle as well. I just installed a new 5.7 Turbotweak stock chip and the idle issues are gone. Cars runs a lot better. Forget the race gas an just run 93 octane. That's all I do and my car runs just fine with no knock. I also have the stock unadjustable waste gate actuator as well. My 2 cents.

 

[ITSAV6]

X2 on a good chip, lot easier than removing the cat. It will run 1000 times better. You could add an alky kit for less than the cost of the cheapest drum of race gas and you won't kill the O2 sensor with the lead.

 

[jasjamz]

Just add Turbo Tweak Chip and some injectors and be done. Put the old stocker in the ashtray. Forget mixing gas and all those other worries. If you have a leaky failing 30 year old injector....problems will come! Make the wise choice here. Real car guys will understand and the others wont even notice.

 

[Pronto]

I ran 100 ul for a while in my car b/f getting the alkycontrol kit. The Sunoco station down the street from me used to sell it. It was great but got a little expensive. You certainly could benefit from 100 ul with a TT chip and hidden mods if you want to look "factory" stock but make more power safely. You could get a used cat converter and gut it, hog out the exhaust elbow, get a take off stock filter box and mod it for better air intake with a free flow filter, bell mouth the stock turbo inlet and intercooler, get an adjustable actuator and run higher boost, etc. I would get the injectors flowed at the minimum and a fresh 255 fuel pump. I friend of mine got his "stock" GN to run 11.9 on drag radials with a host of hidden mods. He picked away at it for a while.

 

[Nick Micale]

http://www.schmidtsgasngo.com/race-fuel-prices.html

I do not have a converter on my 87 all stock GN now. I do have the original prom and I will not be changing it because I want to keep my 87 GN more or less as close to original as possible. I can put the factory converter back on if I want to one day. Only take a few minutes. It only has 10,350 miles on it now. I've owned it for a year now but have never really spooled up the turbo much for fear of melting a piston top with detonation with today's not as good premium gas.
Any opinions?

Thanks
Rodney

Since my original car has 9500 miles that I purchased new, my situation is very close to your's, no cat and no engines mods except for the air filter, and it will run into the 12's.

I did modify the original wastegate so I can adjust the boost, and it is set about 20 psi. The fuel pump died in the 90's, so that was replaced with a TTA pump.

After a couple tanks of pump gas, only 110 leaded race gas has always been in the tank.

Forget about using crap pump gas as it will start loosing octane in about 3 weeks. Also, most pump gas now contains some alcohol which is not good for rubber lines and other components?

The only downside is the O2 sensor may last only a few years, but a Denso replacement is only about $20.

It would be smart to use 110 leaded race gas exclusively, especially if you use a non-stock chip, and you will have a damn quick car for the street which will be safe and reliable with little expense!

 

[626gn]

http://www.schmidtsgasngo.com/race-fuel-prices.html

I do not have a converter on my 87 all stock GN now. I do have the original prom and I will not be changing it because I want to keep my 87 GN more or less as close to original as possible. I can put the factory converter back on if I want to one day. Only take a few minutes. It only has 10,350 miles on it now. I've owned it for a year now but have never really spooled up the turbo much for fear of melting a piston top with detonation with today's not as good premium gas. So my idea is since I will probably only drive my GN at most 300-500 miles a summer (at best) is to keep mixing in some race fuel to bring up the octane so I can run it flat out occasionally and not worry about knock. This place shown above is fairly close to me. But look at all the race gas options! Which to use?? Maybe just that lowest cost leaded? Searching for higher octane fuel locally I find some saying that some higher octane gas just has some additives to raise the octane and is not really high quality high octane fuel. I want to think I should stay away from that type of higher octane fuel? I'm pretty sure all the race fuel sold at this Shell station is all high quality. They seem to be the biggest supplier in the Milwaukee area for race fuel. If I get the 110 octane I am thinking I can add maybe 2 1/2 gallons to each tank and that might be enough to insure I do not have any pre-detonation (knock) at the factory boost level?

Any opinions?

Thanks
Rodney

Here are my thoughts for what they are worth, having fought the "keep it original" battle (and lost) for years with my GN. By now my guess is that your 29 year old beauty already has replacement tires, battery, brake switch, maybe even a new brake accumulator. This is probably just the tip of the iceberg in terms of replacement parts already on your car, whether you realize it or not. Not to mention you already said you don't even have a catalytic converter. I get the whole "keep it close to original" thing but your car is already no longer original from a purist standpoint. Most guys who know these cars can easily point out things that are not stock on your car with a quick glance. But those same experts will never know you don't have a stock chip. Given all the non-original parts that are on your car already, it really makes no logical sense to insist on running that stock chip, which you already know could be detrimental or you wouldn't be asking the question. Hope this helps put things into perspective.

 

[bison]

I would look for 100 octane unleaded street gas.


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[duber3]

a little bit pricey but it totaly worth it
http://www.vpracingfuels.com/download/Unleaded-Extreme-Spec-Sheet.pdf

 

[Mera]

I was told by the previous owner who has owned 4 (One a GNX) and he told me that to install a new prom one has to cut the gray plastic retaining plug to open the door to the ECM in the passenger foot well. Once opened it will never look stock again. Is this true? For now it is my reason to not change the prom. He told me with a smile on his face that this mattered for originality. And I want to stay close to original whenever possible. I can also just never spool up the turbo too much like I have driven it since I bought it. I'm OK with that. I lived thru the muscle car age and had lots of HP and fun. At half throttle still a joy to drive and the look of a GN is just top shelf IMO. Get so many looks from others. Used to drive my 348 around. No guys would look me when I was looking at them. Even at gas stations all the guys just looked the other way. F you and your Ferrari. No so with the GN.

I'm maybe going to go to that Shell station and see what they have to say. They list 2 guys names there for the race gas. I bet they would have some input. Again I hope to add maybe 2-3 gallons of 110 per tank just to get an honest maybe 94 octane. My other idea is to fill it with 100 or so and drive it hard for one tank. Then back to half throttle.

Thanks
Rodney

 

[Boost231]

Time to do some research here. That's not true at all

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[fastblackracing]

The plastic button will come out with some finesse if you are careful to replace the chip. There is a top section that has a plastic button in it also that will have to come out. I think kirbans may still sell new ones.

Does your car start idle and drive without issues now? If so you can certainly retain the stock chip as it is
really a decent chip performance wise if the drive ability is good. But the only way to get more boost
this way is to modify your wastegate rod.

I would look into any unleaded high octane gas very carefully as I have seen first hand some very bad
corrosion in the fuel system from high octane unleaded....I think it was sunoco gt unleaded 100 IIRC.
I would look for something that someone on this forum has run it for a while succesfully as a source of info on this.

In my opinion here is what you really need....a modern updated chip that will allow you
to run a few more pounds of boost without having to modify the wastgate rod since you want to remain
as stock as possible, You should also put at a minimum a 233 bosch regulator that is stock appearing....they are easy
to change and will allow more fuel to go with the better chip......and you likely need a new/better fuel pump as the original fuel pumps barely had enough capacity when they were new....again this is easy to change and no one will ever know.

If you get a chip and do not change the regulator make sure to let the chip guy know this as pretty much all chips are
made expecting to have 43 pounds base fuel pressure and your stock regulator is only 37 pounds. They can
compensate for this in the chip if you ask for it.

Then get the VP leaded 110 and just keep it in there....your only going to use maybe 2 tankfulls a summer
and you will have the maximum protection that you are looking for and if the chip can raise your boost
from 13-14 up to 18-19ish it will be much faster. And with the 110 leaded vp the exhaust smell is awesome,
only downside is you have to change the O2 sensor and spark plugs once in a while.

Or just put the 110 vp in and see how she does, I am not a big fan of mixing gas, I prefer to get the car setup
for whatever you want to run and leave it there, you never know what you are getting from the consumer gas pump.

 

[Pronto]

I ran 100ul for 2 years no issues. At the time I have a TT 100 oct chip. Ran great. Switched to Alkycontrol b/c it was close to $10 a gallon. If it was as cheap as E85 is now, I would have stayed with it.

 

[Mera]

fastblackracing posted some very good info. One issue: My GN was undercoated (probably at the dealer). They sprayed the gas tank but kinda left the straps uncoated. But the straps have some overspray on them. So changing the pump will probably be very noticeable. I could spray the tank and straps afterwards flat black (which would look better anyways). But also remember I am not in any way looking for more HP. I just want to be able to drive it and floor it occasionally and not have to fear putting a hole in a piston.

I have been putting octane booster in but I don't expect that to help much.

I also have no problem just driving it at half throttle forever. HP is cool but the thrill of driving a very close to all original 87 GN is satisfying enough for me.

It does start and idle reasonably well. A little iffy the first minute but not terrible. After the first minute it seems to be just fine.

One thing I want to think is normal is that at a dead stop and in gear it feels like it wants to over ride the brakes some. Like it has 1000hp and is saying let me go. I want to get going.

Past that it runs and drives like a new car off the showroom floor. Even smells new inside yet.

Thanks
Rodney

 

[Johnnie]

I am with you on keeping your GN as stock *as possible* as mine is an unmolested 32k one. BUT, I found the stock chip to be unacceptable as it had a very rich cold idle. Swapped it out with the TT stock replacement and really improved drive ability. Idles much better and like you, I very seldom go WOT and if I do mat it, it's for a very short time. I can do that now with a little more confidence knowing that I won't hurt something.

A little off topic here, but , even though you want to keep it as stock as possible, you should definitely change the body bushings . Makes a really big
difference. Even though mine is a pampered garage queen, most of mine were either very loose or had fallen out. So if you do that, you can keep it factory stock and improve drive ability too.

 

[Mera]

A little off topic here, but , even though you want to keep it as stock as possible, you should definitely change the body bushings . Makes a really big
difference. Even though mine is a pampered garage queen, most of mine were either very loose or had fallen out. So if you do that, you can keep it factory stock and improve drive ability too.

This is interesting and kind of a bummer. I'll look at mine. My GN seems to be solid yet. I would not look forward to having to do this.

Thanks
Rodney

 

[Mera]

Stopped at that Shell station today. They owner would not comment much because he can't say something and have it not work out for someone but: He told me the only race gas I could use of the 20 or so they sell is the VP 110. Everything else is for certain race cars in certain classes. OK. So I bought a 5 gallon can for $47. No added taxes etc. He gave me the number for the supplier and their support help line. So I called. I told the guy I had 92-93 octane in my tank and wanted to raise my octane 3-4 points or so. He told me it would be 5 gallons of pump gas to one gallon of the VP 110. That would give me around 96 octane. I show around 3/4 tank right now so that should be around 12ish gallons. So I'll be adding 2 1/2 gallons of the VP110. The can is 5 gallons. Will be enough for 2 tanks. I might just keep doing that as long as I own this 87 GN. One 5 gallon can might just last me all summer. At worst I get one later this summer. Should I worry at 96 octane?

He also told me the gas stations that sell it with a typical gas pump and is stored in under ground tanks are not the best because the tanks are vented and the octane will diminish over time because of that. So I'll keep buying it in the steel cans. He says it has about a 2 year life span if stored in the steel cans. If you put it in plastic gas containers it again looses octane over time.

Thanks
Rodney

 

[Pronto]

That's a crock of shit. You can "run" several of the fuels they sell other than the 110 leaded. Again, the 100ul would be fine. He may be hedging on selling b/c the fuel he is selling is "meant for off road racing", and not technically supposed to be used in a street car.


Some octane boosters work. Cal Hartline has tested them on a dyno with a car makings some serious power. The downside of them is they turn the combustion chamber, sparkplugs and exhaust pipes a funky orange color. They do get expensive though.