2000 gtp

[Aaron]

Cheaper than a new engine

[CincinnatiFiero]

Considering its not really an option you kinda wasted your time on the math. Why cheap out and cheat yourself on HP and risk the motor? Really? Especially if you drop pulley sizes you should cruise around for 93 not the paltry 91.

[p8ntman442]

Ive got plenty of straight ethanol sitting around...............


I an get 93 2 minutes from my house, I didnt realize you had to run premium, but now I do, and now I will.

Shit I used to run the stuff in my Passat, and that thing ran like shit anyways.

[Aaron]

It's not that you have to, it's just cheap security for an engine prone to knock and piston failure. And KR is bad for mpg, power, and engine life. So premium ftw.

[CincinnatiFiero]

At the very least it will pull timing and be slow, which why have the GTP if it pulls timing and sucks.

E100 that bitch.

The gas door on the Regal GS's says PREMIUM UNLEADED ONLY on the dash and gas door, does the GTP have that on it?

[The Dark Side of Will]

For a long time, GM computers have been able to "knock test" the fuel by inducing knock under light load conditions, and use that info to figure out what fuel the engine is running. They then change ignition maps based on calculated fuel octane. Northstars and LT1's have been doing this since the early '90's. Low octane won't hurt the engine... just make it slower.

[CincinnatiFiero]

LS1s do it too, they get better mpg on premium too. So take the HP and the MPG, and run 91+

[The Dark Side of Will]

My dad's Datsun with L99 ran ok on 87 and knocked down 25 mpg. My dad's cheap, so he'd always run it on 87.

That engine has 9.9 compression under iron heads. I tried 93 at one point and was quite surprised at how much more smoothly it pulled at high RPM. I think I remember that it got noticeably better mileage also. I have no before/after dyno or strip info on it, however.

[CincinnatiFiero]

On 3800pro they discussed the mpg gains on G8s with 87 vs 93 and it was like 3 or 4mpg IIRC. Which in my book is significant, and thats how you get all 320hp or whatever it is. (Yeah I know BHP)

[AkursedX]

In HPTuners there are separate timing tables for high and low octane. I've never touched my low-octane table, but there are 10* differences in my cruise timighing from my high to low octane.

High octane timing at cruising speed and loads is ~40-42* vs ~32* timing for low octane. That's where the mpg difference is coming from.

[The Dark Side of Will]

I've heard that the real boon for the coil-per-cylinder ignition on the LS1 is that it can go to 50 degrees or even more ignition lead in light load cruise.

[CincinnatiFiero]

50*! crap. Tuning for low octane is stupid, why there is even an option I have no idea,

[Jinxmutt]

I'm running in the 40s for timing on my 3800 with the LS1s. I'm also running close to 16afr. I don't imagine my exh valves will be around for much longer but it seems to cruise just fine with no surge.

[CincinnatiFiero]

(warning this ON topic)

You should consider a ported blower housing, that will help get intake temps down and help your mpg along with add some power. ZZP and Intense Both offer good fenderwell intakes which a must and a good place to start. I like Intense but that's probably just because they are 2 hours away from me and I have gotten a lot of good advice from the guys there.

[p8ntman442]

the car comes with an intense or injen or some kind of fwi that starts with I.

[p8ntman442]

Fail, all this time later the deal is off, and I'm working on getting my deposit back.


See new thread on new car. '01 s80 t6