mid-high 12's

[Slow91z]

Just for reference, my car ran 13.07@104...1.97 60'

I have, stock turbo, stock intercooler (spring cleaning done), slightly upgraded injectors like 32 pounders (only because the originals were shot), traction bars (previous owner installed em), Pacemark tires on 16" AR wheels....110 oct, 21 PSI, dynotech race chip...on a cold night.

Basically what I'm saying is after you do the "safety mods" (scan tool, FP, etc.) just crank up the boost with race fuel and a good chip, slicks if you can't get it to hook, and you're gonna be close.

 

[NEARING]

Gut or ditch the cat too.

 

[Razor]

Originally posted by kshef
my O2s are at 803 at the LOWEST point!
i have no knock
boost at 16psi

i like to stay a tad rich, but is this too rich?
i was told these cars love to run lean and i could lean it out to about 780 and gain 20hp but run the risk of damage
is safe to run 780 range if you have no knock?

You run the least amount of O2's without knock. I run typically 730-750's. Guys that race these cars will see 680-700's. So 800 is way rich..but if you drop fuel pressure and lean it out, it will have a higher tendency to knock.

Whats Race Gas

 

[kshef]

what would happen if i turned the boost up a little and leave everything the same?
i was under the impression that o2 levels needed to be 780 or higher....i know this is immpossible but if you had lets say a 500 o2 reading and 0 KR everything is fine???

 

[Razor]

To increase performance, you have to increase octane, or improve breathing. Guys that have front mounts typically can run 20 PSI boost on pump gas. for example.

I dont think you'll see 500's unless your O2 is bad. On 93 octane and 16 PSI boost..780-800's is typically as lean as you can go on some cars. You increase boost, it will knock. You also can run more boost if you reduce timing within the chip. But trying to get power from 93 is futile. Once you taste 22-25 PSI on high octane or alky..you wont drive the car at 16 PSI.

hth

 

[kshef]

Once you taste 22-25 PSI on high octane or alky..you wont drive the car at 16 PSI.
QUOTE]
haha...i love it
i think understand what your saying now

ok so if i wanted to run around 18-19psi i would need to run 100 oct. or so, right now the car is basically stock

in the future if i was to do all the above listed mods, would the car be any faster tuned the same way it is now--800 o2, 93 octane, 16 psi???

 

[Razor]

The car will only be faster if you can improve airflow through the motor. Boost is a restriction. Take out restrictions, now the car can make more power at the same boost number..if airflow where to be improved.

Like if you did heads and cam, the car at 16 PSI will now be much faster..but will also detonate more since it makes more power.

Your always going to be fighting octane with a small displacement turbo motor, especially in stock form. Running straight 100..not mixes will allow you to up the boost to 20 PSI.. but when you fill up with 93..back down to 16 land.

At 5 bucks a gallon for high octane fuel, now you see why alcohol kits are so popular. A good alky kit pays for itself in no time flat.

My car runs 27 PSI on 93 octane w/methanol all the time.. no changes in the way the car is run at the track vs the street.

 

[kshef]

so octane is the main thing here
how much does a good alcohol kit cost? the alcohol atomizes and mixes with the air and fuel right? any reliability issues running alc, injection?

thanks for all the info...i thought i knew a little about these cars but found out i dont know jack
i'm used to newer supercharged 3.8s

 

[Slow91z]

Originally posted by NEARING
Gut or ditch the cat too.

My fault, I have a dump pipe also...totally forgot.

 

[Blown&Injected]

Originally posted by Razor
Like if you did heads and cam, the car at 16 PSI will now be much faster..but will also detonate more since it makes more power.

Are you sure about that?

I thought the increased efficiency of the heads help to run more boost with less KR

 

[Razor]

Originally posted by Blown&Injected
Are you sure about that?

I thought the increased efficiency of the heads help to run more boost with less KR

My own personal experience, coupled with experience of cars 10 times faster than mine specifically 3.8's.. yes.

Yes if you clean up the airflow by installing a bigger turbo, front mount, heads, cam, etc.. you can harness more power on 93 octane at way lower boost levels. But heres the reason I say this, on a stock GN, you do the bigger turbo, front mount, bigger TB, and i've seen cars run in excess of 20 PSI on straight 93. Once you do heads and cam..forget about that 20+PSI on 93 by itself.

My buddy has a TTA that ran 11.93 at 114 at 16 PSI boost. Yes big heads, cam, stall, gears.. Do you think he could run that car on 93 since the boost was only at 16?.. two head gaskets latter should answer that. At 11-12 PSI that car would start to ping, even using a 15 degree timing chip.

Can you run 1000 HP on a 3.8 on 93 octane? No you cant..there are limits to everything. And it will cost cubic $$$ to make a small motor run efficiently on 93. Let alone a car driven on the street sucking in oil vapors through the PCV, having unknown octane due to multitude of fueling stations, condensation in fuel, etc.. many variables.

On a race car that only sees the track, the inside of the motor can be kept really pristine and clean. You dont buildup carbon on the pistons, combustion chambers are also pristine, all these things play a major role on detonation.

Hows that for an answer.

 

[Razor]

Originally posted by kshef
so octane is the main thing here
how much does a good alcohol kit cost? the alcohol atomizes and mixes with the air and fuel right? any reliability issues running alc, injection?

thanks for all the info...i thought i knew a little about these cars but found out i dont know jack
i'm used to newer supercharged 3.8s

No difference in motors.. first and foremost, you'll need a scantool to monitor knock retard(scanmasterII is typically the choice). The fuel system has to be upgraded to support the additional power the motor can/will make now that it can run at higher boost. Simple 340 Walbro and hot wire kit will do it. This is a must. An adjustable fuel pressure regulator, spring cleaning procedures performed, obviously new plugs, wires, fuel filter, etc.. normal maintanance stuff has to be up to date. A low timing street chip also makes tuning a system in easier at higher boost levels. You'll probably end up needing a heavy duty waste gate actuator to be able and raise the boost past 21 PSI. these are available from most Buick vendors. A cheap bandaid are those bleeder valves or boost controllers with a knob.

As far an alky kits.. you have your options. You are more than welcome to cruise through my site and get ideas. The alky section also has lots of information. Click on my link below for info/pictures.

Hope this helps

Julio

 

[kshef]

is this right....
high octane fuel combusts at higher temperatures, preventing premature detonation
alc. cools the intake charge, which cools the air/fuel mix..preventing premature detonation..or does alc. enhance the octane level???


your right about the turbo 3.8 and superchrg 3.8 being the same motor, but a lot more goes into tuning these turbo cars

 

[Weazel]

Originally posted by kshef
is this right....
high octane fuel combusts at higher temperatures, preventing premature detonation
alc. cools the intake charge, which cools the air/fuel mix..preventing premature detonation..

Now I'm no RAZOR here, but that's the correct part of the statement as I understand it. You cool the charge when the alky evaporates, so therefore the relatively low octane fuel doesn't ignite, since the temps are lower.

800 on your O2s isn't bad, is that in a quarter mile-ish run? I'll typically see 780-800 in the 1/8th, figuring it'd drop deeper into the 700s in the quarter, which is about where I wanna be.

If you JUST wanna go 12s, and don't wanna be pushing her too bad, I'd say crank up the boost a little bit and make yourself a couple gallons of homemade octane boost per tank (2 gallons of Xylene, a quart or two of mineral spirits, and 6 oz of Mystery Oil). That'll boost you by 3 octane points or so, which will be nice.

Alky...if you get it...forget about "just" wanting to go 12s. I'm running 21 psi, stock turbo and injectors on pump gas. It's in the 12s with minor tuning, and it's just too damn easy to NOT go faster.

Well, I'm rambling now, but I'd say you're some octane boost away from 12s now. Give her a little more boost, and let it rip.

 

[GrndNatnl]

So you guys are saying that if I port my heads, that I'll be more prone to getting knock on pump gas and 16 psi in street trim? Doesnt really make sense at first. I figured helping that air flow into the cylinders would make it more more efficient. But I'm assuming that "extra" efficiency means: More of the boost is entering the cylinder, therefore causing more knock... thus meaning not as much boost is needed to charge the cylinders or create a given amount of horsepower. Is that the correct theory?

I run about ~ 16 psi, 94 octane, Thrasher 92, 30 lb Tomco's, stock turbo & IC, all the basic stuff in my signature. My 02's range from 760 to 830 (all over the place; depending on temp I guess). If I nail it from a dead stop idle, I usually see 1.2 to 3.6 (sometimes more) degrees of KR at the very end of 1st gear, right before the shift. Then it goes away. If I ease into it from a roll, no knock. Does this sound like its running right? Or if its tuned alright?

I was looking to have a set of heads ported in the future. Would this mean I would require less boost to obtain the same amount of HP?

 

[Razor]

That is the exact benefit of running alcohol..since it burns, is of higher octane(like 110) and cools the charge air temps..you can see a win win win scenario.

In laymans terms,
When you port the heads, yes you will make more power on 93 since the airflow is increased. And becuase the airflow is increased the air isnt as stacked inside the motor and doesnt get heated up as bad through the turbo. Yes you will make more power at 16 PSI..but if you are on the edge of detonation at 16, keeping everything the same, the car will make the same power at a much lower boost number. Upping the boost becuase of the airflow deal will let you run a little more boost, but not 16 as you once did. Unless you do a bigger IC, Turbo, etc..stuff that brings air temps down.

There is an octane requirement for power..and its based a lot of intake air temps. Heat that air coming into the motor..regular 93 has a hard time keeping the pace.

Heres something to think about. My car I can run 26-27 PSI on 93 w/alky stock IC,TB,Plenum, cam,heads,headers,etc.. But on c16 the most I can run is 24-25 due to the high intake air temps without the alky. I see close to 200 degrees on my car without alky at 24-25 PSI. And those temps coupled with a high timing race chip..are hard to control the detonation.

If your car has never had the heads off..leave them things alone until your running at least mid 11's.

HTH

 

[GrndNatnl]

If hot air is more prone to detonation, why must I increase my fuel pressure a little when its cold outside. I thought the denser air required more fuel, since its just that.. denser.. more air.

I'm not questioning anyone here, I'm raising my hand and trying to learn and better understand the theory behind these motors.

Also, if the air isnt stacked up in the heads and getting hot with the increased air flow due to porting, why wouldnt you be able to run MORE boost, since the air charge isnt quite as hot from stacking up as much? Or would it actually balance out?

By balance I'm understandnig this: First factor meaning: Increased flow through the heads into the cylinders, requires less boost to charge the cylinders as efficiently. This meaning higher boost actually charging the cylinders can create more detonation. The balancing factor being that since the air isnt being 'stacked' and heating up as much, the slighly cooler air entering the cylinders would prevent as much detonation.

So how would this result in a track or dyno test? How would a car with stock heads running 16 psi compare to a car with PORTED stock heads running 16 psi? Can anyone explain experience on this?

Does colder air require more fuel pressure or octane, or does hotter air require more fuel or octane? This is also where I get really confused.

This topic is getting really good. I'm trying to take all this knowledge into my brain here. Keep it going guys. I appreciate you trying to hammer it into my head.

 

[Slow91z]

OK i think I can answer some of those questions.

When it's cold outside the air is denser (obviously) and you have to up your fuel pressure to correct the Air/Fuel ratio, not to prevent detonation...although a proper Air/Fuel ratio is crucial to prevent detonation. Did that make sense??

Now colder air is harder to heat up to the detonation point, so cold air with a proper Air/Fuel ratio makes the most power provided you have enough octane to support the boost you are running.

Now your octane is what determines the detonation point...So if you have high oct. and cold air, with a proper Air/Fuel ratio you have a fast car.

So when it's cold SHOULD be able to run a little more boost as long as you up the fuel pressure to compensate for the density of the air.

Now Alcohol cools the air AFTER the intercooler, AND it adds Octane, so it kills 2 birds in 1 stone so to say...i still say with a good intercooler and C16 you wil make more power, but Alky has got to be the best compromise you can get for the street.

HTH and I can expand on this if anyone has any questions.

 

[Razor]

The cooler the air the denser it is. And the more you can cram into a motor. Cramming more air into a cylinder and not increasing fuel to compensate for the extra air will lean the car out. Creating guess what

Alcohol saturates the air with fuel, hence while cooling the air it also burns and makes more power.

Boost is a restriction. You cannot develop boost unless there is a restriction. Make sense so far ?

Reducing the restriction lets more air flow. This increased air also needs fuel to offset it and keep your air fuel ratios steady. Hence why we upgrade injectors, fuel pumps, etc.. to be able and drop more fuel into the motor when needed. When you increase air flow through a turbo thats innefficient, it will heat up the air as well compressing it.

16 PSI on a car with ported heads and a 224/224 cam and 16 PSI on a stock motor are a world of difference.

The hotter the air coming into the motor, the higher tendency for it to detonate. Try working out in a sauna.. you'll understand really quick about hot air. look at the 84/85 GN's without IC.. thats another example.

How do you make power, more air..more fuel..but then comes controlling the detonation.. by keeping the air charge temps low and/or increasing the octane. C16 race gas no matter if your at 10 PSI or 35 PSI if the charge air into the motor is at 300 degrees..it will ping. So even octane has a limit on controlling detonation.

This is in laymans terms..hope it helps

 

[Slow91z]

True Oct. does have it's limits, if the octane was to high it wouldn't even burn...I guess what I was trying to say in my last post was it's all about balance, the right temp, with the right Octane, with the right boost, with the right amount of fuel.