Hey all, im looking for about a 50-60 hp boost from my TPI L98, I really want 350RWHP, i just love the number....so im looking for about 420-440FWHP. I intend to run a 150 laugh-gas shot, (hopefully less depending how much power i can get out of it N/A) that combined with 50-60 hp from my tpi will make me a happy man.

mods definitly to be done....
- bleed brakes, if the feel doenst stiffen up then the 2 piston Baer kit.

- fuel pump, exhaust, Headers (Which ones? any recommendations?)


- Alum driveshaft (exact one depends on availibily)

- i have stock posi and 3.27 so that should be good.

So any ideas to squeeze less then 60 pony from tpi? possibly carb?

thank ahead of time/.

 

Headers, I'd go with headmen or Hooker,

Cat back, as long as its 3"

Intake, I'd go with a Stealth Ram,

Heads will make the biggest jump in power,


Look at some of the other posts, on the subject...

 

Deffinately bleed the brakes, maybe multiple times. that's like 20 hp every time you bleed them, you'd be there real quick.

But really, you could probobly get 50-60 hp by doing:
full exhaust, SLP 1.75" are the best shorties for hp, and hooker 1.75" longtubes are pretty much the standard for all out 3rd gens.
Most cat backs flow pretty well and any 3" should suffice.
Like mentioned above, the Stealthram is a cost effective intake setup that has alot of potential. You could go with high flow TPI parts but it would cost alot more than the stealthram and most likely make less hp. do a search on it and read up.
A cam would help the above mods, something along the lines of 218/224 duration at .050" and a LSA around 112.
If all you want is 50-60 hp that should do it with stock heads. I'd say with a decent tune you're looking at 260-270 rwhp with this.
Just my O2 though.

 

Add a 75 shot of Nitrous on it.

Or, get a set of vortec heads, SDPC vortec TPI intake and some decent runners.

Either of the two will give you 60 or more HP.


Now making 350 rwhp naturally aspirated from a TPI 350 is a hard task to accomplish, but it is possible.

 

LOL you should direct him to the debate that's been hanging around.

Anyways, if you want long-term flexibility, you'd want to go with high-flow parts, like a Stealthram, AFR heads (or similar), a bigger cam (like LT4HC), and a lot of tuning.

If you're just looking for a good boost, then what 1Bad91Z suggested is a great choice.

I don't know what you have now, but in all likelihood, 50-60 more HP will NOT get you to 350 rwhp. That's will require parts like what I first listed.

 

I think he want's 350 rwhp total, including the 150 shot. So depending on how much hp he actually gets from the n2o, he may only need little more than 200 rwhp n/a. what does a stock L98 dyno at, 160-170 rwhp?

 

Am I the only one that thinks him wanting 420FWHP and 350RWHP is funny?

 

I think you're the only one who noticed!!

And yes, that's hilarious!

Guess you'll need different gears for the front drive wheels, man!

j/k

 

wow is that true?i got a 220hp '88 L98, does it really get down to 160-170 rear wheel hp? seems like a lot...

 

Yeah, I was disappointed to hear that at first, too - but it's true.

 

wow, so the elusive 300hp at the rear wheels mark is a far far reach...im sorry to hear that

 

FWHP=Fly Wheel HorsePower

Is your goal to gain 50-60 RWHP or obtain 350 RWHP? If you are still running the stock exhaust & manifolds then you are probably running stock everything else. If that is the case your goal of 50-60 HP gain is more realistic. To get 350 RWHP you need about 165 more RWHP than what you have now.

 

Somehow I managed to understand the FWHP thing the very first time I read it, yet by the time the "Front-wheel" joke came up I didn't think about it, and managed to make an *** out of myself. That's crazy lol.

 

fly wheel hp is more commonly refered to as bhp. I saw FWHP and thought... ahh jesus either a troll or some dumb a**.

 

Alright alright I get it, I ment 420BHP and 350 RWHP (AFTER the Nos shot)....altho 420 front wheel and 350 rear wheel hp would be cool on an iroc....haha....Im off to the dyno on the 29th of Nov, where im going to get my exact numbers from. But im looking for about 50-60 extra N/A horses (at the flywheel) plus NOS of 150 (I would rather not have to use nos but price to power its a great ratio) would net 350 or there abouts afterword at the rear wheels. (hopefully both of them, i do have posi but who knows). If at all possible I would like to use less n2o, prefferably a 100shot, or even 75, but that doesnt seem practical.

 

Oh after carful consideration I've decided to go thru with several mods. Including but not limited to Stealth Ram, Nos, Headers (and full exhaust along with it), 25# injectors (seems to be in order considering that im almost doubling the flywheel hp, and slp's are only 100bucks). And eventually, a holley commander 950 computer... for some tuning.

Most probably ill end up starting with some chassis stiffening and the computer first (perhaps a full stealth ram kit w/computer and injectors is in order) that why i can see exactly what im working with. Im informed that switching to lighter driveline components ( driveshaft, ect..) nets greater efficiency in regards to flywheel to wheels horsepower (aka, less rotating mass equals more power to the wheels and less to spinning a bunch of overweight steel)

we'll see, maybe ill sell the Iroc and go mustang....





(j/k) <----please dont hurt me

 

My L98 stock (no cam, heads)... Mods: headers, air foil, tb bypass, air filter, catback, probuilt 700, 2400 act, msd 6al, coil and wires.

Dyno'd 211 hp and 313 tq with an exhaust leak at the wheels.

 

Thats impressive fireturd350. It seems that alot of people on these boards spend alot of money and alot of (probably) really great stuff and they get disapointing figures, and some others do simple and basic mods and seem to build decent power at a fraction of the cost.

 

Nope, it's not. SDPC has a vortec L98 crate motor that does 357hp and 406ft/lb torque. All he would have to do to get around 350rwhp is to go vortech heads (the ones with high lift springs of course) and the LT4 HOT CAM....plus gods of tuning and probably a new chip. With the vortec tpi baseplate, some long tube headers, and 3 inch cat-back he should have plenty of of power. And then to add the funny gas.....:lala: :lala: ......can someone say fun?????

SDPC sells a package of the vortec heads with springs good for .570'' lift and the TPI baseplate for like...$1200 I think, not positive about that but I could check. Then the LT4 cam and some 1.6RR and he's good to go.

 

I really don't call picking up 20 hp and 45 tq good or money well spent... but it's a start I guess.

 

oh, well i thought that the firebirds have 10-20 less hp then the camaro's, in which case...its a bit more hp and tq gained, i guess its what u start off with i guess. Plus you must remember these cars are NOT in their prime, we are all porbably a bit lower then the factory suggests we are, the face u dyno's over that is great news.

 

well i meant getting 300hp with a stock L98 withought spending a grand or two on motor parts...

how much horsepower can be expected with a pair of decent heads (like under $600 for both) a good cam (like the LT4)?

 

Instead of the LT4 cam which is designed for a short runner intake that has a lot more top end, Id sugest getting the cheapest cam you can in that SDPC TPI crate and grab an LPE 219. Im almost 100% sure you will make more power.

 

this is going to sound stupid, but im not sure i understand you...you said get the cheapest cam out of the scoggin dickey and a LPE 219 (isnt that an LT4 cam?)

 

well you could go with the Torquer SR's. They are in Jegs, can be had for around $700 for both, retain stock intake bolt pattern so no need for new intake, have larger valves (2.02"/1.60") and have LOTS of beef for porting. they should be excellent for what you are looking for. Then like bigals87z28 said, get a cam more suited for long tube runners and you'd be about set. If you do go with the hot cam, switch to HSR or superram. that way the top end would be better suited with the intake.

 

well, in my case my L98 is carbed....i didnt know there were different cams for different intakes...interesting. i have a edle. performer intake

also, how much power can be applied to the motor before you have to start replacing the pistons/crankshaft etc?

 

till it blows. You can go racing over and over and over and blow your engine after only 300hp. But I would start thinking of putting in hyper or forged pistions at 350-400hp.

 

Agreed....cast usually will hold up to about 300hp, then I would put in hyper. After about 500 I'd definitely be switching to forged....everything. Also, H-beam rods are stronger than I-beam and are a bit lighter as well......just a little fyi if you get into rebuilding or something.

 

FWHP= Fly wheel HP. Too much R I C E in your diet

 

at the crank, correct?

and whats a nice cam for a carbed L98

 

Yes at the crank. Wouldn't make sense to do it at the rear wheels if things are breaking before the power gets there, ya know. Personally I am not a carb guy so I really couldn't help you out with your cam selection for the L98. It also depends on what intake manifold you are running and how high you want to rev the engine. But I am not gonna give you false advice cuz I really haven't dealt with anything carbed yet. sorry.

 

It all depends on how you use the engine. A cast crank can handle more than 400rwhp no problems is you do not rev it past 6k on a regular basis. (l-98) But higher RPMs above 6k on a regular basis can wear out the stock crank bearings quick.


Pistons? If you are spraying, then keep it under 100 shot if using stock pistons.

If you do rebuild your engine and are using spray, I always would suggest going forged.

Forged crank?? If you want to turn high rpm, or if you are using soem kind of forced induction, then forged cranks are the ticket.

If you do decide to buy a different crank when rebuilding an engine, always look into stroking it. It will not cost much more to go with a 381 (383 if you need to bore the block on rebuild) than a stock stroke crank.

 

I can guarantee you its not that!

 

The Eagle H-beams rods I bought were heavier than the stock type rods my stroker kit came with originally.

 

Odd, I have always seen H-beams advertised as stronger and a weight savings over typical I-beam rods. It might have to do with the type of metal that is used in the rods and if they are PM or forged....I would think forged steels are denser than a stock type rod.

 

no problem. i'm running the edlebrock performer intake and i dont want to rev high

 

The H-beams may be lighter than I-beams (don't know for sure), but they're definately heavier than stock rods. If layed side by side with a stock rod, they look a lot beefier.

BTW, all SBC rods have been forged since 1955.
The PM rods are forged too, but using a different technique.

 

I always thought I beams were lighter than H beams. But H's were stronger (resists twisting better). Also cast (factory forged) is a lot lighter than aftermarket forged... due to the aftermarket forging process of course.

Actually I read a tech article saying "In the ’60s and ’70s, American Motors, Cadillac, Buick, and Pontiac all used cast rods in a wide variety of engine designs."

If you wanna read about billet, titanium, factory forged, aftermarket forged, or cast rods check out this article.

I found THIS acouple months ago.

 

I never knew rods got into that many catagories Learn something new everyday. But like I said, I have seen H-beams advertised as a weight savings over I-beams; I just assumed they meant stock since all stock are I-beams. Sorry for the confusion. But hey, this should help out anyone who wants to learn more about rods!

 

Yeah, no problem. I'll brag a little bit now. My 4340 forged I beams I got off ebay were Ultra LW version (around 550 grams). That's what's going in my new 383.