stock dyno numbers

[Nick M]

Not true, many GM cars were 'underrated' from the factory

No, they were the kings of BS on the HP scales. Only the recent LSX family has gone the other direction, and that under rating the F-body so it was lower than the Corvette.

 

[88SupraT]

it was done in 3rd gear and it was on a mustang dyno

Given it was done in 3rd that can explain a little, 3rd gear is still considered an "underdrive" gear which will produce more torque rather than the 4th and 5th gears since they are the "direct drive" and "overdrive" gears. But given it was on a mustang dyno which in most cases that I have seen produce readings at least 10% lower than a dynojet if calibrated right I would say the mustang dyno you were on was not calibrated correctly, as both your horsepower and torque are quite over the norm given your mods. In my case I have many more mods to my engine + tune compared to you having just exhaust, pistons + mhg and I only put down 269whp 285rft/lb on a mustang dyno in 4th gear run. Then again I'm really no expert in this so this just my opinion given what I have seen and little I know.

 

[te72]

If you are seeing wheel power exactly where the published fwhp was when new...

Err... did someone install your 7m sideways?

Not true, many GM cars were 'underrated' from the factory and 20-40% reduction? Most manual cars retain as much as 7% drivetrain loss whereas autos are closer to 20%.

No, they were the kings of BS on the HP scales. Only the recent LSX family has gone the other direction, and that under rating the F-body so it was lower than the Corvette.

Back in the 60's/early 70's, sure. My 01 SS was "rated" at 335hp. I forget where the dyno chart ended up, but the car in reality made something like 244whp, or 250whp, something like that. Was kinda sad, but it wasn't in the best of condition either.

Still, if you can't extract more than the rated hp from an LS variant, you're not trying too hard.

OP, define "stock" for us. My "stock" 1j put out 320whp at just 12psi. 3" exhaust, cams, and head porting being the only mods, everything else was stock. And that was only at ~6300 rpm. Mine isn't exactly stock, but it isn't exactly far from it either.

 

[IJ.]

Change 1 thing and it's NOT "stock"... :nono:

 

[Nick M]

OP, define "stock" for us. My "stock" 1j put out 320whp at just 12psi. 3" exhaust, cams, and head porting being the only mods, everything else was stock.

Actually, you have extensive mods by most reckoning. Head porting is the most serious thing. A bigger turbo to many is a smaller mod, as it is a bolt on. Then again, a GT42 is one heck of a bolt on, so I don't know if "bolt on" is still minor. Speaking of GM giving fake numbers....the first LS6 in the Chevelle was rated to 450hp. If you have been to the track and one is stock, you will see them trap mid to upper 90's. Forget ET. I will allow for gearing and tires. But that speed is not 450 hp. Yet the GSX Stage 1 and its 335 hp stomped that Chevelle in ET and speed. When they are stock.

 

[ThunderZTA]

Back in the 60's/early 70's, sure. My 01 SS was "rated" at 335hp. I forget where the dyno chart ended up, but the car in reality made something like 244whp, or 250whp, something like that. Was kinda sad, but it wasn't in the best of condition either.

Still, if you can't extract more than the rated hp from an LS variant, you're not trying too hard.

im pritty sure the rating of BHP for an 01 SS should be 320 BHP, only f-bodies to be rated 335 were the firehawks from 2000-2002 early...if it was an auto those hp numbers are about right, those 4L60E were notorious for robbing horsepower. but if you had the T-56 6 speed then something was definetly not right.

I was fortunate in my 00 Z28 made 288hp/307tq and the BHP for them was 305hp/320tq

 

[iruyle]

Err... did someone install your 7m sideways?

Sorry, I used fwhp to refer to flywheel hp (published data). It even took me a min to figure out what the Hell I meant when I reread it. LOL

 

[ThunderZTA]

Speaking of GM giving fake numbers....the first LS6 in the Chevelle was rated to 450hp. If you have been to the track and one is stock, you will see them trap mid to upper 90's. Forget ET. I will allow for gearing and tires. But that speed is not 450 hp. Yet the GSX Stage 1 and its 335 hp stomped that Chevelle in ET and speed. When they are stock.

The LS6 produced a claimed 450 BHP. It has been suggested that the LS6 was substantially "under-rated" and actually produced something on the order of 500 horsepower as delivered from the factory. Recent engine dyno tests have proven that the 1970 LS-6 engine makes over 470 hp and 500 lb/ft torque in stock configuration ( stock compression ratio, stock camshaft, stock intake and exhaust manifolds). Current 1/4 mile times and MPH of a 1970 Chevelle equipped with 100% factory stock LS-6 engines and modern tires are turning very low 13 second times (13.08) with trap speeds of 110+ mph. not bad for a 4000 lb. vehicle

The GSX stage 1 that was also producing the low 13s in the 1/4 mile was the 455ci that produced 360hp(closer to 400)/510tq

little more torque, 3.64 gears > 3.31 gears, and 150 lb.s lighter then chevelle in 1970 is why they ran close times

 

[IndigoMKII]

http://www.chevelles.com/forums/showthread.php?t=153110

 

[Nick M]

im pritty sure the rating of BHP for an 01 SS should be 320 BHP,

I think those were under rated to keep them under the Corvette. They were pretty solid around 280 rwhp and then later 300 (give or take) with the revisions. They made the same as the Corvette on a dynojet, but rated lower by GM. Most people don't look at dyno numbers, just what is in Motor Trend.

I was fortunate in my 00 Z28 made 288hp/307tq and the BHP for them was 305hp/320tq

I think that is about normal for those. They ran quite strong, and were better than 305. As you see.

Recent engine dyno tests have proven that the 1970 LS-6 engine makes over 470 hp and 500 lb/ft torque in stock configuration ( stock compression ratio, stock camshaft, stock intake and exhaust manifolds). Current 1/4 mile times and MPH of a 1970 Chevelle equipped with 100% factory stock LS-6 engines and modern tires are turning very low 13 second times (13.08) with trap speeds of 110+ mph. not bad for a 4000 lb. vehicle

I haven't seen it. But I don't spend every spare hour at the track anymore either.

The GSX stage 1 that was also producing the low 13s in the 1/4 mile was the 455ci that produced 360hp(closer to 400)/510tq

I recall seeing that 455 do as you say. But not the Chevelle. And I would love to have a Chevelle. I'll take mine red with black stripes. I wouldn't go with the LS6 because it would get a modern LSX, around 434 and maybe a T66.

 

[MkIII FTW]

Butler Performance in Tennessee recently blue printed a Pontiac 421 Super Duty as it came from the factory no changes were made and it put out 100hp over the 1960's advertised amount. The Buick GSX Stage 1 put out the most tq ever produced in the era. I would build Gen 1 GM power any day before I touch LSX. But that's just me.

 

[57trimMKIII]

I consider my car "near stock" - Apex'i intake, RT downpipe, and a Tanabe cat-back

Back in February it laid down 235 rwhp (unknown torque) @ 9ish psi on a dynojet (auto)

 

[ThunderZTA]

I think those were under rated to keep them under the Corvette. They were pretty solid around 280 rwhp and then later 300 (give or take) with the revisions. They made the same as the Corvette on a dynojet, but rated lower by GM. Most people don't look at dyno numbers, just what is in Motor Trend.

[/QUOTE]

the LS series F-bodies were under rated... they planted more power then the Corvette because of the IRS on the corvette

I wouldn't go with the LS6 because it would get a modern LSX, around 434 and maybe a T66.

[/QUOTE]

what 434 and t66 are you reffering to?

 

[MkIII FTW]

[/QUOTE]

what 434 and t66 are you reffering to?[/QUOTE]


Perhaps he is referring to an LSX punched out to 434cid. As far as t66 it doesn't ring any bells. If we are talking about transmissions then maybe he meant t56.

 

[te72]

Actually, you have extensive mods by most reckoning. Head porting is the most serious thing.

Huh... I never really thought it to be extensive myself. The porting was obviously the most time consuming part, but all that was done was taking away material that Toyota put there, nothing too crazy. I mean, the guy who did it for me knows how to shape a cylinder to match your desired engine behavior, but still. Didn't seem like a big deal to me.

Only other mods I did, I did in the Home Depot I worked at at the time.

im pritty sure the rating of BHP for an 01 SS should be 320 BHP, only f-bodies to be rated 335 were the firehawks from 2000-2002 early...if it was an auto those hp numbers are about right, those 4L60E were notorious for robbing horsepower. but if you had the T-56 6 speed then something was definetly not right.

Mine was a T56, and it came (when I bought it at least) with the SLP exhaust, supposedly good for an extra 15hp (according to SLP anyway).

I agree on the auto cars being kinda sluggish, at least in stockish form. They must have had terrible gearing, every time I raced one, once I shifted to 4th, it seems like they always dropped about 3 cars back instantly. Powerband, what's that? :nono:

Was definitely a quick car though, so I'm leaning toward my car just wasn't feeling that good that day. We were also a little over 2000' elevation in Phoenix.

I would build Gen 1 GM power any day before I touch LSX. But that's just me.

My only thing with the old GM v8's is the vast majority of them are heavy as shit, and I like turning every bit as much as going fast, so unless we're talking an old ZL1 engine... gimme an LS series.

Perhaps he is referring to an LSX punched out to 434cid. As far as t66 it doesn't ring any bells. If we are talking about transmissions then maybe he meant t56.

Think T66 turbo.

 

[ThunderZTA]

Perhaps he is referring to an LSX punched out to 434cid. As far as t66 it doesn't ring any bells. If we are talking about transmissions then maybe he meant t56.

Yeah it would have to be a bored 427 or something cause im not aware of any LS series motors being 434ci lol....

i only know of the T-56 and the T-6 (AKA T-6060) that replaced the t-56.....maybe he knows of a hybrid that combines the two lol

Mine was a T56, and it came (when I bought it at least) with the SLP exhaust, supposedly good for an extra 15hp (according to SLP anyway).

I agree on the auto cars being kinda sluggish, at least in stockish form. They must have had terrible gearing, every time I raced one, once I shifted to 4th, it seems like they always dropped about 3 cars back instantly. Powerband, what's that? :nono:

Was definitely a quick car though, so I'm leaning toward my car just wasn't feeling that good that day. We were also a little over 2000' elevation in Phoenix.

Geeze that sounds very low if you had the T-56 w/ SLP exhaust...but like you said there are alot of variables. some days cars just seem to say "screw you" lol....Me personally i love SLP parts for GM because they (SLP) work well with GM cars so if they say itll make that power it generally does if not even a little more once combined with other things. I use their y-pipe, loudmouth II, UD pulley, thermostat, MAF, and flo-pack

I think what hurt the Auto LS1's more then anything were the differential rear end ratios. Automatic LS1 cars come with 3.23s or 2.73s from the factory, and six speed LS1 cars have 3.42 gears....but a build 4L60E is a very good way to go if your a 1/4 mile person

 

[Nick M]

[/
what 434 and t66 are you reffering to?

CID and a turbocharger.

 

[ThunderZTA]

CID and a turbocharger.

Ah ok so a 427 bored out to 434 and a T-66 turbo...now i get it

 

[Nick M]

Not a 427, a newer LSX block from GM or even World products.

 

[ThunderZTA]

Not a 427, a newer LSX block from GM or even World products.

the LSX bow tie iron block comes as a 427.... It is bored thrity over which makes it a 434 ci.

Unless you know of an actual block that is a 434 and not a 427 bored .030 over thats the only way to get it from GMPP