: N* rebuild....hmmm what to add to my mod list

11-09-06, 12:23 AM
What to do, what to do?

As some of you know I have a N* in my 94 GTP. Its time already to have it rebuilt. While its apart im debating on what to reinstall on it when it goes together.

Who here has any parts from www.CHRFab.com?

My thoughts were; head work, cams, bigger injectors, and some tuning...

who here has some serious performance mods? and where did you get them?


11-09-06, 11:15 AM
Head gasket?

How's the holley?

11-09-06, 06:04 PM
well yeah i mean new pistons and gaskets, timeserts and everything...

BUT what else?? anyone, mods, anyone?

Holley is working out great, now just need to get another tune for the colder temps..

11-09-06, 08:33 PM
Oh, I thought you were rebuilding it because something broke...

I would consider the 280-88ish cams from CHRF, new springs, and forged rods. Also consider forged pistons... with that, you should be able to raise the revlimit to 8500+, which would sound AWESOME, let alone the power gains ;)

obviously you'd need to upgrade to 32#/hr injectors or there abouts to support those mods.

Does the engine stall when the fan kicks on?

11-09-06, 11:29 PM
yeah so far this is what im doing, new pistons, bearings, head gaskets, springs, cams 280* (AJ, the owner of CHRF talked me out of the 288*), chrome valve covers, upper intake, and alternator case, and then bigger injectors... I will also be making an aluminum driveshaft and getting a stage 3 or 4 clutch as well to uphold the increase in power..

that should do it for the build, I already have headers, intake and computer tune..

has anyone purchased CHRF items?

I have the fans on a manual switch eldo, and no they dontb

11-10-06, 09:32 AM
I don't see rods in that list though... that's the first item you need if you want to raise the rev limit... The weak bolts and/or thread engagement will only let you take it to 7500.

If you're going to be tearing it apart anyways, consider radiusing the windage holes between the cylinders. You can gain back some pumping losses that way.

I know a guy that's got 272 cams, and it sounds the same as stock. What did Alan say about the 288's?

11-10-06, 11:05 AM
I'm out of my element here, a good machine shop may be able to assist. We used to enhance performance by balancing and blueprinting engines. Improving oil passages, balancing parts like the rods, pistons etc. Hardening parts, adjusting clearances and so on.

11-10-06, 09:22 PM
alan talked me out of it because i will be driving my car every day and that would be too aggresive.. yes sorry rods will be on that list as well..

11-12-06, 09:44 PM
ttt :)

11-13-06, 05:38 PM
Ever consider forced induction and nitrous? Correct me if I'm wrong but isn't the GTP FWD? If so you might want to consider RWD or AWD conversion.

11-13-06, 08:13 PM
weister42, I take it your not familiar with customgtp's project. He's already converted it to RWD for the purposes of road racing if I'm not mistaken. Ridiculously cool project.

By the way CustomGTP, have you uploaded any new pic's to your page recently. Last time I saw it the car (mechanically) looked to be almost complete.

11-14-06, 11:02 AM
Hey a fellow WI'ite.. Im in Milwaukee. My GP was FWD, I converted it to RWD.

11-14-06, 03:54 PM
i dont like boosted motors as much.. at least for my application. It will remain N/A.

Danbuc: yes I drive it everyday, it still need plenty of work itll get this winter but its driveable :)

11-14-06, 04:48 PM
9000rpm 425hp here you come!

What gear ratios do you have in your T56 or T5 or whatever you're using? Final ratio?

11-14-06, 05:20 PM
Borg Warner 6sp T-56 Gear Ratios
1st 2.66:1
2nd 1.78:1
3rd 1.30:1
4th 1.00:1
5th 0.74:1
6th 0.50:1

Final ratios with 3.42 rear (stock GN)
1st 9.10:1
2nd 6.09:1
3rd 4.45:1
4th 3.42:1
5th 2.53:1
6th 1.71:1

11-14-06, 05:30 PM

The 1-2 drop is huge

11-14-06, 05:59 PM
please explain, ive never really gotten too much into the ratio's. although I did look into them some when I figured out how my RPM's at 80MPH were gonna look, just to make sure when I drive it long distances I wasnt gonna be revvin up too high and getting bad gas mileage

11-15-06, 08:01 AM
Wow at the RWD conversion! That is beyond cool! :thumbsup:

11-15-06, 01:34 PM
please explain, ive never really gotten too much into the ratio's. although I did look into them some when I figured out how my RPM's at 80MPH were gonna look, just to make sure when I drive it long distances I wasnt gonna be revvin up too high and getting bad gas mileage

Your 6 speed is worthless as a race transmission. 4th gear takes you to 150ish mph

In an ideal scenario, you have a tightly spaced transmission. That is- whatever speed you're travelling, you can ALWAYS be in the powerband. Say the magic number (HP peak) is 7000 rpm. You want to hang around 7000rpm as long as possible. If the 1-2 shift drops you to 3000 rpm, you will be a LOT slower than if 2nd gear starts at 6000rpm. (for example)

4000rpm is a lot, but if you have a nice wide torque curve, that will make up for it. Whatever you do to your engine, make sure your transmission keeps it in the power band. In your case, I would highlight 5000rpm - 8000rpm (or whatever your redline is) and max out the torque in that range... even at the expense of torque below 5000rpm. If you take a look at the chart, the only time you're below 5000rpm is <30mph.

If you swap in some 4.11's or something, you can make that time even shorter ;)

11-15-06, 04:42 PM
cool, I see it now.. I just didnt understand the graph. Yeah well itll be good for revvin the piss out of it lol... til I blow it up and gotta do it all over again, oh well.

gotta keep the 3.42's in it for travel reasons but yea

11-15-06, 10:05 PM
1600 @ 70mph is pretty dang good..... I don't remember exactly, but I think I run about 2300... but I've got the stock 3.71 final.

You should go for 4.11 gears... Still <2000rpm highway in 6th

11-15-06, 10:31 PM
true thats not toooo bad, never did the calculations for 4.11's.. hmmmmmm

anyone got any mods?

11-16-06, 08:11 AM
I have heads sitting in my garage waiting to be ported and installed w/cams and springs... It's my daily driver though, so I can't afford any down time, so I doubt I'm going to do anything for a long time...

Are you using the stock N* alternator?

11-17-06, 11:03 PM
no im using a 3.1L alternator, i just made brackets and tensioners for it.. I may upgrade when i get my radio and everything for my car installed this winter

01-10-07, 12:52 AM
yeah not looking to really do custom work to the engine... it already is RWD