Current SLP options, Large siamesed intake runners, Tri-y stainless steel headers,SLP low restriction stainless steel exhaust, SLP Computer chip, and SLP cold air induction package.

What would be the best mods to do next, I have a air-foil and a underdrive pulley kit
to install,

*what about a AFPR? and how do you set pressure at idle with vacume plugged, or under load? is it worth it (performance) to do?

*would the 52mm TB be worth the money and performance on my setup?

What would be the appox performance gains
from the above mods?

*Also I have the NX kit, what would be the max jets you would run, with the SLP prom some say it advances the timming allot so dont run over 125hp. NX said you dont have to back off on timming, but I havent talked with them direct.

Your response is appreciated, Jim

Here is the car, I got it last Saturday, this is my 3rd car off of ebay

http://cgi.ebay.com/ebaymotors/aw-cg...ndexURL=0&rd=1

 

I would go with the exhaust upgrade first. Nothing like custom 3" Mandrel bent exhaust front to back with headers and Y-Pipe (SLP). A chip is nice, I got mine from Performance Resource, haven't used it yet though, I got it just after I put the car away.

Nice car by the way ;o) I have a 1988 GTA... I Love It!!

------------------
1988 Pontiac Trans Am GTA L98 5.7L, Black on Black with 114,000kms.

Best ET 14.559 @ 95.25MPH
Custom 3" Stainless Exhaust Y-Pipe back (High flow Cat and Flowmaster Mufler)

 

Here's my suggestion for what it's worth.
1. Port your plenum. There's some power to be found by smoothing everything out and radiusing the port exits as well as getting rid of the wall directly behind the throttle body bores.
2. Install 1.6 rockers. For your application, a set of Comp Cams roller tips will work fine.
3. Adjustable Fuel pressure regulator.
www.geocities.com/dzperf

------------------
D&Z Performance
"Putting Power to the Pavement"

 

nblanchard, did you read his post? He already has all that stuff, it's an SLP car.
I agree w/ HiTech5 porting the planum is a good way to go, also look into a high flow base. (best would be to do those at the same time and port match them to your runners.) You don't need a 52mm TB yet, and you can make your own AFPR. I don't think 1.6s will be worth the money. A higher stall coverter and maybe some gears, and SFCs. Nice car, welcome to the site.

 

Thanks for the insight guys, anymore

Hey Vader, Glenn91L98GTA, need your advice too.

BitchinCamaro,nblanchard, thanks for the kind words




[This message has been edited by SLP-GTA (edited November 22, 2001).]

 

...not recommending anything...
just sayin ...SWEET CAR...

------------------
1989 G92 Iroc 305 5spd 3.45 posi
mods: airfoil, MAF screens, flowmaster 80's, K&N's, TES headers, Catco hi flow cats (dual of course).

Other:
Tints, Eclipse CD8051 HU, Nakamichi pa504 (50x4 watts), Polk 4x6's, Polk 6x9's, Xtant 1001x amp (1000 watts), 2 xtant X-series 12 inch subs= people know i'm comin' a block away

Just ordered these (at midnight b/c i'm an idiot): Taylor Spiro Pros(8mm), and an MSD Blaster coil

Soon= ram air, ported intake, cam, ignition

 

Oh... sorry guys... I thought he was thinking of getting that stuff. Then deifnately port the plenum, large tube runners and a higher flow intake base. Then you may want to beef up the suspension for better hook up. I have to work on that on my car.

------------------
1988 Pontiac Trans Am GTA L98 5.7L, Black on Black with 114,000kms.

Best ET 14.559 @ 95.25MPH
Custom 3" Stainless Exhaust Y-Pipe back (High flow Cat and Flowmaster Mufler)

 

As others have said, take the plenum and runners off and do some major port matching of the runners to the plenum as well as remove and smooth the entry area behind the throttle body where the 'EGR walls' are. There is a tech article for this procedure on this site for porting the plenum for regular seperate runners and then, if you want to really make a difference in your power band, siamese the plenum to match the SLP siamesed runners and port the runner dividers down a few inches. I have SLP runners (among other things) on my engine that I ported down an inch or so and matched to the plenum, and my engine pulls very nicely past 5500 now. Doing a mod like porting the intake system really won't give you much of a higher peak power output, but it will broaden the power band immensely. A higher flowing TPI base wouldn't hurt either, but if you were going to dive in that far, you might want to get a MiniRam or SuperRam setup.....

The other thing I would suggest is to get into burning your own PROMs. You can have total control over when your car does anything like lock the torque converter, speed governer, rev limiter, highway mode sub routine enable, etc... All of those things can be manipulated in the PROM, as well as the usual performance things such as timing and fuel injector settings. Even on a completely stock setup you can vastly improve on the fuel economy and performance of the engine. And don't think for a second that an off the shelf PROM, like that SLP one, is helping you much - if at all. Off the shelf PROMs like that just can't be tuned as accurately as a PROM should be if you want every pony and every mile per gallon out of the car (most of them barely make use of the Highway Mode routine that can boost your fuel economy BIG TIME).... If you are interested, read the tech article on this site for PROM burning and start doing some searches on the DIY PROM Burning board for things you want to know. There are a lot of people here that will help you along the way.

A 52mm TB is likely not needed at your level of mods but will help when you get more extensive mods installed such as cam, heads, etc...

An AFPR is a helpful tuning tool and allows you to somewhat adjust the fuel mixture of your car at WOT. Changing the settings in the PROM is a much easier and more reliable way to tune WOT, but the AFPR will get you some flexibility. Using the AFPR in conjunction with PROM burning is a great way to lock down the mixture completely. If your car is running correctly, mixture wise, the AFPR will not gain any power for you. But if your car is in need of tuning, the AFPR will help you eek out those last few ponies. To tune correctly with it you will want a scantool to monitor the engine.

As for nitrous, I am not much of an expert on it, but all of the people I know that do run it would tell you that the timing can be left to stock settings with a 100 shot and below. I would say backing off the timing a few degrees wouldn't be a bad idea if you used the full 125 shot. This is another area where burning your own PROMs would do wonders for your tuning.

Some ideas for ya.......

------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

Damn..... nice grab. How much did you end up paying? $8500?

 

very nice car. not a bad price either.

------------------
'89 firebird formula tpi
custom cold air,gutted maf(just screens),52mm tb,ported plenum,edelbrock runners and base,headers with 3" catback,tb coolant bypass,afpr@44 psi,msd 6a w\blasterII coil,3.73 posi,sf connectors and corvette servo

 

Matt87GTA, Thanks for taking the time to write all of that great info. Prom burning seem to be one of the best mods everyone has consistantly recommended. Is the SLP prom setup bad? look at the pic showing the exhaust,@20k miles the tail pipe look clean, would that indicate a lean condition, it would seem the AFPR with fatten things up and help on the top end.

Does anyone on this board burn chips for sale??

I paid asking price, John the prior owner
took well care of the car, as you can see, I'm surprised nobody picked it up sooner, it had 2 days left on the auction and no bids, so I call him direct and told him I'll take it, Im glad I did.
I gave the my three boys a power ride today they were impressed (they loved the second gear spin) and the hard bang in 3rd
gotta start them out early,


[This message has been edited by SLP-GTA (edited November 17, 2001).]

 

Well, it is really hard to say about those exhaust tips looking really clean... He may have just kept them extremely clean like the rest of the car. But if they stay that way now that you own it - even after some WOT operation of the car, I would say you may have a bit of a lean condition. A quick check of a few of the spark plugs will tell you a lot about how the fuel mixture is... Spark plug reading is still one of the most useful tuning tools - especially if you don't have a scantool!!.... But you really do need to get a scantool on it and see how it is running to pass judgement on that SLP PROM. It is pretty likely that it is not going to ruin anything or cause any problems, but it is definately leaving a lot on the table as far as the fuel economy and performance goes....

If your car is actually running lean, raising the fuel pressure with an AFPR will only help it when you are at WOT. Now that just might take care of everything, and maybe it won't..... The regulator has vacuum applied to it and, depending on which one you get, you will only be able to increase the pressure in the fuel rails at WOT when extremely little or no vacuum is present. I like to use the fuel pressure as a sort of fine adjustment on my fuel curve at WOT and use the PROM calibrations to get it as close as possible at everything but WOT.

I think my post before does a pretty good job of pointing out that burning PROMs is very good idea. And it is even more of a good idea - pretty much a necessity - for those of us that do some heavy mods to our cars.

Geez, I didn't even comment on the car!! It looks VERY nice.... One of the cleanest I've seen in a while... I only wish my GTA was in that kind of condition....

Good Luck!!

------------------
1987 GTA L98 MD8
355, TFS Heads, LT4 Hot Cam
My GTA

The Minnesota F-body Club

 

The car is great shape!! I would do mods that cannot be seen from the outside and leave the car as-is.

This one may be worth some good $$$ in about 10-15 years.

 

I'm jealous, that car is beautiful. It was definately a good deal for $8500.

------------------
1986 IROC, fully loaded, Mini Ram'd 383, Art Carr 700R4, Accel DFI, 12 bolt rear, etc, etc......

 

you guys are way too nice, Thanks. I plan on only doing mods that are easy to return back to original, and keep the miles down to 6k year.

I really appreciate ALL of the great responses. 3rd gen guys are cool