Torque
Thread Starter
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Torque
I've read countless threads about building HP-
but what about building torque?
I'm setting up my winter modding plan for my l98.
I'd like to hit 300HP at the crank, which I think is very do-able.
but what about TQ? Has anyone ever tried to build a huge torque engine and sacrifice some HP? Seems like that style of engine would be more fun around town.
but what about building torque?
I'm setting up my winter modding plan for my l98.
I'd like to hit 300HP at the crank, which I think is very do-able.
but what about TQ? Has anyone ever tried to build a huge torque engine and sacrifice some HP? Seems like that style of engine would be more fun around town.
Race Director
Joined: Sep 2004
Posts: 13,793
Likes: 0
From: St. Peters MO Sometimes you have to prove yourself by doing alot of killing or alot of dying...
I used to ask the same question until one simple fact was pointed out to me. When you are really getting on her you are running the motor up to redline most of the time... especially in racing. When you shift you only drop about 1200-1500rpm in the band so you still remain at the top end of the curve. It is better to build a motor that accents that curve if this is the style of driving you are looking for.
Race Director
Joined: Dec 2002
Posts: 13,345
Likes: 230
From: SCMR Rat Pack'r Charter Member..Great Bend KS
Originally Posted by mikey whipreck
but what about building torque?
Increase rpm, or
increase torque.
Unless you take the appropriate steps to maintain torque at higher rpm, the only way to increase hp IS to increase torque.
Build a torque-monster and, unless doing so kills your rpm capability, you will increase hp.
Larry
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
What year L98 do you have?
The basic recipe is to retain or accentuate the TPI tuning while increasing air flow:
-add 1 5/8" FL headers and true duals or hi-flow cat & cat-back
-hi-flow air intake system with Accel base and AS&M runners
-port the plenum and upper runners
-do a nice cam with good lift but not too much overlap
-install small runner heads with 2.00"/1.56" valves
-under drive crank, over drive alt pulleys, Al is preferable
Depending on the year of L98 you can get to 300chp with stock heads and cam and modified TPI setup.
To enhance street fun while maintaingin stock highway perfomance install a 2,000-2,400rpm TC and TransGo shift kit in your A4.
The basic recipe is to retain or accentuate the TPI tuning while increasing air flow:
-add 1 5/8" FL headers and true duals or hi-flow cat & cat-back
-hi-flow air intake system with Accel base and AS&M runners
-port the plenum and upper runners
-do a nice cam with good lift but not too much overlap
-install small runner heads with 2.00"/1.56" valves
-under drive crank, over drive alt pulleys, Al is preferable
Depending on the year of L98 you can get to 300chp with stock heads and cam and modified TPI setup.
To enhance street fun while maintaingin stock highway perfomance install a 2,000-2,400rpm TC and TransGo shift kit in your A4.
Team Owner
Joined: Sep 2001
Posts: 62,067
Likes: 1,723
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
C4 of Year Finalist (performance mods) 2019
You are going to increase the HP at the same time, theres not much getting around it.
The engine is already a torque machine, I would say the only way to substantially increase the torque with the TPI left alone is to increase the size of the engine. 355, 383, 406+.
All youre going to have then is a torque peak that is higher numerically, but HP's peak rpm is going to drop alot.
Unless you make the ports on the intake and heads smaller to increase port velocity, which itself will lower the peak rpms even further.
The engine is already a torque machine, I would say the only way to substantially increase the torque with the TPI left alone is to increase the size of the engine. 355, 383, 406+.
All youre going to have then is a torque peak that is higher numerically, but HP's peak rpm is going to drop alot.
Unless you make the ports on the intake and heads smaller to increase port velocity, which itself will lower the peak rpms even further.
Racer
Joined: Jul 2004
Posts: 434
Likes: 0
From: Santa Barbara Minnesota
"Torque Monsters"
I have an 86, bored to 355ci. just rebuilt the motor with Trick Flow cam/heads (420hp. Street Bracket Kit). I kept the TPI because the Torque is way cool. Most recent Mustang Dyno results show 200 ft. lbs. torque @3000rpm. over 400 ft. lbs. @3800rpm. great kick in the pants, at 5200 it's all over though. Unfortunately it was run in 3d. gear (700R4) which was slipping, it blew up later. The new tranny just got done, it's supposed to be good to
600+hp. 600+torque. (Raptor level 3 w/Torque Drive kit) 2300 converter stall
Time for a "Supercharger!"
"tight turns
and a good line..." Good Luck!
600+hp. 600+torque. (Raptor level 3 w/Torque Drive kit) 2300 converter stall
Time for a "Supercharger!"
"tight turns
and a good line..." Good Luck!
Last edited by #70SM2; Nov 10, 2004 at 02:24 PM. Reason: add a fact
Pro
Joined: May 2003
Posts: 682
Likes: 1
From: Annapolis MD
i'm pretty close to the 300 rwhp and 400 rwtq goals i set for my car with stock motor and tpi. just minor bolt on's and exhaust with alot of tuning.
headers, chip, cut lid w/ k&n filter, alittle more timing, with muffler elims, and maybe a few other bolt on's would put you easily into the range you are looking for with out a rebuild. i haven't even lifted a valve cover yet on my car.
it's very doable especially if you take the route 65Z01 said
headers, chip, cut lid w/ k&n filter, alittle more timing, with muffler elims, and maybe a few other bolt on's would put you easily into the range you are looking for with out a rebuild. i haven't even lifted a valve cover yet on my car.
it's very doable especially if you take the route 65Z01 said
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Thread Starter
Melting Slicks
Joined: Jun 2004
Posts: 3,032
Likes: 4
Good points, all 
I have an '85 l98, rated at 230hp/330tq (goal is 300/370 at the crank)
I didn't necessarily want to build a torque only engine, but I did not want to sacrifice any TQ for HP.
Most seem to agree about the headers (1 5/8") and duals, and that's where I'm gonna start. I had also planned for porting the plenum, and adding accel runners, among other things. I had not thought about underdrive pulleys, and I think I could handle that.
But-
I do not want to get too deep into the internals of the engine, such as a cam-swap, because I don't think I'm mechanically inclined enough.
everything else mentioned is helpful, and is on my list. All except for changing the Intake manifold.
65z01, I looked at your site, and it seems like you LOST power switching to a larger manifold? Is that true, or were those just bad runs?
I have an '85 l98, rated at 230hp/330tq (goal is 300/370 at the crank)
I didn't necessarily want to build a torque only engine, but I did not want to sacrifice any TQ for HP.
Most seem to agree about the headers (1 5/8") and duals, and that's where I'm gonna start. I had also planned for porting the plenum, and adding accel runners, among other things. I had not thought about underdrive pulleys, and I think I could handle that.
But-
I do not want to get too deep into the internals of the engine, such as a cam-swap, because I don't think I'm mechanically inclined enough.
everything else mentioned is helpful, and is on my list. All except for changing the Intake manifold.
65z01, I looked at your site, and it seems like you LOST power switching to a larger manifold? Is that true, or were those just bad runs?
Team Owner
Joined: Dec 2000
Posts: 90,675
Likes: 304
From: SE NY
Cruise-In II Veteran
I feel that I lost a little low end with the siamese base (similar to siamese runners, but cheaper) but the 2,000rpm TC more than compensated. So I think the 20chp gained up top was worth it.
It looks like going with the Accel base and LT runners doesn't cost any low end torque or very little if any.
It looks like going with the Accel base and LT runners doesn't cost any low end torque or very little if any.
