Hi everybody,

I have 1988 Trans Am GTA with L98 TPI engine, all bone stock only without catalysator, and completely 3" exhaust.

I looked so much this forum about increasing the engine power, but can't connect everything in my head , and make a good setup for around 300hp.

Can anyone tell me exactly which components to buy, in order to get around 100hp on L98?

I know the question sounds stupid, but I read the forum so much that in the end I have no idea how and which parts to compose Headers, runners, rockers, cams, injectors... but what exactly to buy, that's the question

Thank You very much in advance.

Best regards!

 

good starting point would be: headers, 1.6 roller rockers, under drive pulley setup. 3.73 gears

 

Do some searches many people include there build specs with there dyno results.

It depends on your budget and the plans for the car. There really isn't any secret formula for power on these cars. It just comes down to how much you want to pay to go fast. If you're just wanting more hp for the strip only many members have used 150 shot on stock good condition 350s with colder plugs and pulling some timing out.

For 300 hp or around there I would just stick with short tube headers. Long tubes are nice but they're a headache.

If you did headers, AFR heads (195 cc), port the intake, roller rockers, and use a ECM compatiable camshaft you should be able to meet your goal easily. Course if you're putting that much money into a stock short block you need to think how many miles are on it also? Are you dumping $2000 of parts into a 350 that has 200k miles or something?

You can have a 500+ HP car but it's probably not going to hook without the normal suspension upgrades (sub frame connectors and etc).

 

Your looking at something like 220-230whp stock on a good running L98 to 320-330whp on a modded L98.

You will have to upgrade intake to all aftermarket high flow TPI or better like short runner intakes like superram, stealth ram, proflow, miniram, etc.

heads will have to be ported out stockers, mildly ported out aluminum L98's, or aftermarket which is more money but makes power easier to come by. 180-195cc will do. AFR/DART/BRODIX/TRICKFLOW/PROFILER, etc...all great heads and most are really overkill for 330whp but i'd rather have overkill heads and mild cam than too little head and big cam to make up the difference.

I've seen here that a mildly cleaned up L98 headed motor with hotcam sized cam (218 deg intake duration, .500-.525 lift or so) with a ported aftermarket TPI or short runner intake can do 320whp.

All depends on the dyno and tune tho. Some put out higher numbers than others

 

What he said. Intake modifications are a must on the L98. Can't make power if you can't breathe

 

start with INTAKE, i swapped a stealth ram in my l98 with headers and some bolt on's. crappy tune but its up there. i need some gears bad and a tune but with stealth ram alone it makes one hell of a difference.

 

Thanks guys,

my car/engine has 52000 miles and I think that it's ready to build up

I don't like nitro, this is street car so I want that power all the time. I don't defined budget for this, but there is no need to buy everything at once.

I spent about 6000$ in last two years to repair the car, because it was in very bad shape, and this is only GTA 5.7 in my country (Serbia). Money is not the problem, but I want to see here is it better to build up L98, or just to buy LS1 with tranny and get 350HP immediately

If I need to spend 3000-4000$ to build up L98, I'd rather buy LS1.

What could I espect from these parts:
First: http://www.firstfuelinjection.com/PDRM1966.JPG
Headers: http://www.summitracing.com/parts/HOK-2460HKR/

As I can see on E-bay, I can buy LS1 engine with auto trans for about 2500-3000$, which is about 4000-5000$ with all expenses to bring it to my country (I have friends who are familiar with importing USA cars via containers). So, for this amount of money, I think that is better choice for me. Correct me if I'm wrong

 

LS1 with headers/exhaust and a tune will do 330-350whp depending on trans and year motor Thats pretty stout.

BUT for 3000 bucks you likely can get that power and exceed it with the L98 provided the bottom end is still in good condition.

If you did heads/cam/intake on the stock bottom end shortblock, you can turn near 6400 rpm and make 350-375whp or more depending on the setup.

I'd go stealth ram if you can, as its cheaper than the FIRST TPI and easier to work with. But the FIRST will do great if you want to go TPI.

Get some heads, like Pro-Filer 195s, AFR 195's, Dart pro 1 200's, brodix race rites 200's or similar range of heads. Put in a 268XFI cam for a good mix of streetability, ease of tune and 350whp power potential. Or stretch it with a 280XFI cam and shoot for closer to 375whp+.

My buddy's car did old AFR190 heads with stealthram and 280xfi comp cam and even tho his valvesprings were bad, it still ran 12.2's in warm air at 112 mph. It only made 330whp before suffering bad valve float. With proper spring control it would have been a solid 350's whp car and went 11.9's or quicker. Probably 114mph+. New style heads would have been a 375whp car easily and mid 11's at 116

 

Quick question Is this a daily driver or weekend car? If it's your daily driver and will be so for a couple of year's Id do an LS1 due to a good balance of power (325hp) and MPG (20 city-27hwy)

If its just a weekend car and have absolutely no plan's on DD just upgrade what you have, Its gonna be cheaper and less of a pain in the *** to get the power you want. Intake, cam, exhaust are a must with decent head's and cam alone you can easily add up to 70hp exhaust 15hp tune 15hp and there it is.

 

Great info

So you think that FIRST TPI with heads and cam is the way to get 300-350HP.

When You said AFR 195 heads, od Dart, do You think about something like this?

http://www.summitracing.com/parts/DRT-13200010/
http://www.summitracing.com/parts/AFR-1040NP/

Which 280xfi cam do you suggest (Price range is between 140$ and 1100$ )?
http://www.summitracing.com/search/?...Ns=Price%7cAsc



I didn't see that Stealth ram is cheaper than FIRST TPI, but never mind.

If I need all these parts for Stealth setup, this is almost the same price as FIRST:
http://www.summitracing.com/parts/HLY-112-503/
http://www.summitracing.com/parts/WND-7540/
http://www.summitracing.com/parts/HLY-534-186/

 

This is weekend car, but also I don't want to make 10mpg car with these modifications

 

Have you seen this?
https://www.thirdgen.org/forums/tpi/...injection.html

You may want to check it out since you're considering the first system.
You should also try to contact Dyno Don or 1989GTATransAm if you plan on keeping TPI, they are board experts

 

Yes, I saw this thread, sounds nice

 

even for cheap you can go with new intake piping with cold air intake piping, atleast 1.6 roller rockers, adjustable fuel pressure regulator, exhaust. but there is always the easiest way of just turbo or supercharging it.

 

box stock FIRST system is a great TPI system and will support all that you need for 320-350whp.

I wouldnt run the 280xfi on that setup unless you wanted to push the limits of the intake, or went with a stealth ram setup. Its really not necessary, that cam can do almost 400whp in the right setup.

the 268xfi is a good 350whp cam, its very mild but with good heads its a powerhouse. I'd run that. it will sound very mild and get great mileage, be easy to tune and yet make power when combined with a good head like Profiler 195's or AFR 195's or one of the better DART/BRodix 200 packages.

What you want is the cam for OEM hydraulic roller motors 87-99 since yours is a 88. usually 250-320 bucks. Dont even need to use XFI series, but they work well. The XE grinds from comp are decent too with 1.6 rockers. IF you dont want comp, Lunati would be a nice choice..they have a nice 268 cam thats abit more aggressive than comps...their voodoo lineup. It will make good power.

Its up to you. Technically you dont even need heads that big to make 320+whp. I've seen mild cleaned up L98 castings make 320whp with a hotcam. Its just nice to have good heads and mild cam to make the big power. Makes more area under the curve and is smoother running. Just my opinion

 

OK, so what exactly do You suggest?

What could I expect from FIRST TPI and Hooker headers 2460?

http://www.summitracing.com/parts/HOK-2460HKR/

Shipping to my country is expensive, so I want to know what could I do with stock heads

Is there any purpose to swap just cam (without heads), after FIRST TPI and headers swap?

 

Do you have a machine shop that can take your stock heads, and cut the spring pockets out abit, and install screw in studs, and do a new valve job?

If so, you can cam it up and make decent power on stock castings but getting to 350whp likely wont happen. With abit of port work and a big cam, it MAY do it like the LT1 guys. Their heads flow a good 20 cfm more stock so the Iron L98s need opened up to compete with that.

 

a box stock first is good up to 450hp NA according to a few people... waaay more than any stockish or midly ported tpi can do.. id say for a stockish look and still retain the tpi look....do this for a budget build

vortec heads (make sure you get them to handle to about .550 lift)
FIRST tpi (you can get the vortec style FIRST manifold that fits vortec heads)
gm hotcam ( very cheap but good streetable cam)
headers
full exhuast
tune

do all of that and you should easily be over 320whp...... im aiming to get at least 1 hp per cubic inch at the rear wheels.... since i have a 355sbc i want at least 355whp and 355wtq.....

 

You can really get that kind of power and 1/4 mi times with a stock L98 short block with AFR's, stealth ram/mini, big cam, and long tubes and bust high 11's driven properly and hooking?

 

Yes as long as car isnt super heavy and most arent. Also proper air conditions apply. You wont get there in colorado 5800' up but say maryland in november with 50 deg air it will run hard.
My iroc with power everything and leather was 3450 lbs with me in it back in late 2000's. Now i am 30 lbs heavier lol but for most part, 3400 lb or so is easy to get to especially if you run separate rims for drag race and skinnies up front. That drops 70lbs by itself

Combination of parts has to work together and car needs to make use out of the power thru chassis tuning