Trying to guess HP
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Trying to guess HP Hello, First post here even though I have been using the site for awhile. I have a 1994 Trans AM, and I am trying to guess how much HP I am making, since I live in California and dyno shops are not around as much. All my engine mods i've done myself include: KNN CAI, BBK 58mm throttle body, Trick Flow intake elbow ,Accel performance coil, throttle body coolant bypass, pacesetter mid-length headers, Hooker Blackheart Cat-back exhaust 3in pipe, 4in quad exhaust tips and i run 5w-30 mobil 1 with KNN long oil filter. Next big project is going to be the Torqhead 24x kit upgrade. Thanks to anyone that can get me a ball park number until I can find a dyno shop near by!
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Joined: Oct 2006
Posts: 992
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From: Euless, TX
If it is a manual transmission, there is not a reason in the world that needs to be tuned. If it is a 4L60E, it needs a tune right away to increase the part throttle line pressure since it is TPS based. The fueling is controlled by the MAP and MAF. Headers don't really change the air/fuel ratio much. I tuned a full bolt on 94 or 95 M6 car a couple of years ago. Moroso intake, 1LE elbow, ported MAF ends, ported intake with a 58mm throttle body, valve springs and NSA 1.7 roller rockers (hardened pushrods and guideplates) and an electric water pump. Car gained about 5 hp and 8 tq. I was able to add a few more numbers under the curve and smooth out the off-idle transition slightly, but there was not much to do otherwise. I adjusted the VE and MAF slightly to get the fuel trims near perfect, but that was only a 3-5% fueling change at most and well within the PCMs adjustment range. If the car had a stock MAF, I doubt it would have needed any changes. That car made 300 wheel and about the same torque. At 15% loss thats 352 at the crank. That car liked 38° of timing and 12.6:1 afr on 91 octane E10.
Last edited by Fast355; Sep 8, 2022 at 03:12 AM.
Also the best test is quarter mile trap speed. My stock m6 trapped 100-101 , after full bolt ons/small cam and tune it trapped 110.
I would suggest getting some good long tubes for the best gains and find a good mail order tuner such as Solomon in Ohio. Good prices and he knows what he is doing.
Also a lot of us get away with the stock optispark without issues, the key is to have the original Mitsubishi sensor in the optispark for reliability, locktite the rotor screws, and seal the optispark with rtv so water doesn't get in and you won't have a problem. Ive had zero issues with the optispark for 9 yrs.
I would suggest getting some good long tubes for the best gains and find a good mail order tuner such as Solomon in Ohio. Good prices and he knows what he is doing.
Also a lot of us get away with the stock optispark without issues, the key is to have the original Mitsubishi sensor in the optispark for reliability, locktite the rotor screws, and seal the optispark with rtv so water doesn't get in and you won't have a problem. Ive had zero issues with the optispark for 9 yrs.
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OP's car made new, what 275hp at the flywheel which is about 240-250 at the wheels. May have about 260 at the wheels now.
The 58TB is doing nothing for power and will soon kill trans without tuning. Put stock TTB back on until you get past 450 RWHP....also the intake manifold needs to be opened up for a 58, if that was not done it really a FU deal
Torqhead swap is a real bad idea on an otherwise stock working LT1 and those $ would be WAY better spent on a head and cam package which done right will add 100hp....with the right tune
The 58TB is doing nothing for power and will soon kill trans without tuning. Put stock TTB back on until you get past 450 RWHP....also the intake manifold needs to be opened up for a 58, if that was not done it really a FU deal
Torqhead swap is a real bad idea on an otherwise stock working LT1 and those $ would be WAY better spent on a head and cam package which done right will add 100hp....with the right tune
Staging Lane
Joined: Aug 2020
Posts: 91
Likes: 14
From: STL
I don't dyno cars for a living so I can only speak to my own experiences, but I agree with the above. There aren't really any mods outside of the headers, and that TB is going to hurt more than help. I would expect around stock HP numbers, maybe less if the car isn't tuned, maybe a touch more if it is.
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This has been gone over many times. The LT1 is around 290-300 fwhp bone stock.
Getting rid of the stock exhaust manifolds is huge.
even those mids are going to be a good gain in hp but long tubes are best.
getting rid of the cats and installing a good flowing catback also helps.
throttle body coolant bypass is worth a few ponies
idc if its an auto or a manual you need a tune to get best gains from mods
you have to have the afr adjusted, the timing set correctly usually around 36-38 degrees, and you esp need a tune with a non stock throttle body.
it is true the 58mm TB is helping zero percent on a stock lt1. You really don't even need a 52mm TB until around high 400s to 500 hp. 58mm for about 550+ hp.
with mid length headers and full opened up exhaust and a good TUNE you should be around 330hp easy.
get long tubes, 1.6 roller rockers, ewp, and tune and expect close to 350 fwhp.
if you want high 300s to around 400 hp you need a bigger cam. If you want major hp you need to get your heads ported by a good porter such as lloyd elliot portworks.
Getting rid of the stock exhaust manifolds is huge.
even those mids are going to be a good gain in hp but long tubes are best.
getting rid of the cats and installing a good flowing catback also helps.
throttle body coolant bypass is worth a few ponies
idc if its an auto or a manual you need a tune to get best gains from mods
you have to have the afr adjusted, the timing set correctly usually around 36-38 degrees, and you esp need a tune with a non stock throttle body.
it is true the 58mm TB is helping zero percent on a stock lt1. You really don't even need a 52mm TB until around high 400s to 500 hp. 58mm for about 550+ hp.
with mid length headers and full opened up exhaust and a good TUNE you should be around 330hp easy.
get long tubes, 1.6 roller rockers, ewp, and tune and expect close to 350 fwhp.
if you want high 300s to around 400 hp you need a bigger cam. If you want major hp you need to get your heads ported by a good porter such as lloyd elliot portworks.
Last edited by 350 groundpounder; Sep 9, 2022 at 03:10 PM.
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An acquitance has a 94 T/A M6, w/Cold Air, K&N, new opti, Mobile 1 5w-30, plugs & wires it dyno'd 245whp on a DynoJet in 3rd gear. Car was speed governed so a 4th gear run wasn't possible. Probably costing ~10 to 15 whp.
Same car got long tube headers, 3 inch SLP Dual/Dual catback, 24x kit coil on plug upgrade, LS1 PCM and expert tuning. Made 326 whp
For the mod's I thought that was pretty good.
Same car got long tube headers, 3 inch SLP Dual/Dual catback, 24x kit coil on plug upgrade, LS1 PCM and expert tuning. Made 326 whp
For the mod's I thought that was pretty good.
Teching In
Joined: Aug 2017
Posts: 19
Likes: 17
From: Treasure Coast of Florida
Go to the drag strip, weigh the car with you in it and make some quarter mile passes.
Rear Wheel Horsepower = Race Weight * ((Trap Speed * 0.00426)^3)
Alternatively, pick up a VC-200 off Ebay and weigh the car at your local CAT Scale with you in it.
Rear Wheel Horsepower = Race Weight * ((Trap Speed * 0.00426)^3)
Alternatively, pick up a VC-200 off Ebay and weigh the car at your local CAT Scale with you in it.
If it is a manual transmission, there is not a reason in the world that needs to be tuned. If it is a 4L60E, it needs a tune right away to increase the part throttle line pressure since it is TPS based. The fueling is controlled by the MAP and MAF. Headers don't really change the air/fuel ratio much. I tuned a full bolt on 94 or 95 M6 car a couple of years ago. Moroso intake, 1LE elbow, ported MAF ends, ported intake with a 58mm throttle body, valve springs and NSA 1.7 roller rockers (hardened pushrods and guideplates) and an electric water pump. Car gained about 5 hp and 8 tq. I was able to add a few more numbers under the curve and smooth out the off-idle transition slightly, but there was not much to do otherwise. I adjusted the VE and MAF slightly to get the fuel trims near perfect, but that was only a 3-5% fueling change at most and well within the PCMs adjustment range. If the car had a stock MAF, I doubt it would have needed any changes. That car made 300 wheel and about the same torque. At 15% loss thats 352 at the crank. That car liked 38° of timing and 12.6:1 afr on 91 octane E10.
Supercharged111, so you are trying to tell us your lt1 makes 350fwhp with stock manifolds and underdrive pulleys which don't really make a difference? Someone is pulling numbers out their *** and it isn't us lol.
Last edited by Supercharged111; Sep 10, 2022 at 04:34 PM.
Tell me you had headers at least because that's stock ls1 dyno numbers.
Actually dyno numbers aren't exact either, Dynos vary greatly. Engine dynos that measure fwhp are more accurate.
I believe car weight and 1/4 mile trap speed tells the best story of a cars power.
Many of us have been around so many of these cars over the years we can guess dyno numbers say within 10-20rw once knowing all the mods the car has. I agree these cars vary from car to car but we generally speak the average as a guestimate for ppl to get an idea.
Actually dyno numbers aren't exact either, Dynos vary greatly. Engine dynos that measure fwhp are more accurate.
I believe car weight and 1/4 mile trap speed tells the best story of a cars power.
Many of us have been around so many of these cars over the years we can guess dyno numbers say within 10-20rw once knowing all the mods the car has. I agree these cars vary from car to car but we generally speak the average as a guestimate for ppl to get an idea.
Tell me you had headers at least because that's stock ls1 dyno numbers.
Actually dyno numbers aren't exact either, Dynos vary greatly. Engine dynos that measure fwhp are more accurate.
I believe car weight and 1/4 mile trap speed tells the best story of a cars power.
Many of us have been around so many of these cars over the years we can guess dyno numbers say within 10-20rw once knowing all the mods the car has. I agree these cars vary from car to car but we generally speak the average as a guestimate for ppl to get an idea.
Actually dyno numbers aren't exact either, Dynos vary greatly. Engine dynos that measure fwhp are more accurate.
I believe car weight and 1/4 mile trap speed tells the best story of a cars power.
Many of us have been around so many of these cars over the years we can guess dyno numbers say within 10-20rw once knowing all the mods the car has. I agree these cars vary from car to car but we generally speak the average as a guestimate for ppl to get an idea.
Ive driven lt1s from bone stock all the way to procharged 383 lt1s.
Dynos are just a tuning tool basically, my current lt1 is around 330rw and is pretty fun. My favorite was my est 420rw ported trick flow headed 383 lt1, just about perfect for street cruising. And then was the overkill for the street the est 600rw procharged AFR headed 383 which was just stupid power. That thing would roast the tires going 55mph down the road.
In the end its all just numbers, we can agree it's either put up or shut up at the dragstrip! Let's see those E.T's and trap speeds to prove your power!
Dynos are just a tuning tool basically, my current lt1 is around 330rw and is pretty fun. My favorite was my est 420rw ported trick flow headed 383 lt1, just about perfect for street cruising. And then was the overkill for the street the est 600rw procharged AFR headed 383 which was just stupid power. That thing would roast the tires going 55mph down the road.
In the end its all just numbers, we can agree it's either put up or shut up at the dragstrip! Let's see those E.T's and trap speeds to prove your power!
TECH Resident
Joined: Oct 2006
Posts: 992
Likes: 173
From: Euless, TX
That's a laundry list of parts to make what mine does with a cone filter intake, manifold back exhaust, and BBK underdrive unrestricted. OP I see dynos all over the place, these cars aren't all that consistent from my observations. The guessing game is dumb, if you want to know hit a Dyno. If you want to pull a number out of your *** to impress your friends, go for it.
Last edited by Fast355; Sep 11, 2022 at 12:46 PM.
TECH Resident
Joined: Oct 2006
Posts: 992
Likes: 173
From: Euless, TX
TECH Resident
Joined: Oct 2006
Posts: 992
Likes: 173
From: Euless, TX
Ive driven lt1s from bone stock all the way to procharged 383 lt1s.
Dynos are just a tuning tool basically, my current lt1 is around 330rw and is pretty fun. My favorite was my est 420rw ported trick flow headed 383 lt1, just about perfect for street cruising. And then was the overkill for the street the est 600rw procharged AFR headed 383 which was just stupid power. That thing would roast the tires going 55mph down the road.
In the end its all just numbers, we can agree it's either put up or shut up at the dragstrip! Let's see those E.T's and trap speeds to prove your power!
Dynos are just a tuning tool basically, my current lt1 is around 330rw and is pretty fun. My favorite was my est 420rw ported trick flow headed 383 lt1, just about perfect for street cruising. And then was the overkill for the street the est 600rw procharged AFR headed 383 which was just stupid power. That thing would roast the tires going 55mph down the road.
In the end its all just numbers, we can agree it's either put up or shut up at the dragstrip! Let's see those E.T's and trap speeds to prove your power!
I dunno... like a groupie I used to hang out at a shop in TX that had a dynojet. They were very meticulous about keeping it calibrated, and this being the mid/late 90's, all the LT1 f-body bros would go there to get their bolt on cars dynoed especially on Fridays and then hit the track. The average I would see out of M6 cars still carrying their cat(s) was around 280rwhp and 310 torque. The torque numbers were always pretty much the same. This was going through at least 10 or more dyno sheets. After exhaust/no cats/shorty headers (LT's were not available yet) they would be around 310rwhp. Can't remember what torque was, but they were all in the very low 13 or high 12 range at ~107mph. Usually with back seats removed. I think bolt-on autos were all around the 260rwhp mark, IIRC. I may not. I don't know since I didn't care about auto cars back then.
