Phil99vette

iTrader: (11)

It seems to me as if alot of people are using alot of combos from different vendors. Has anyone actually figured out what parts make a 450rwhp car different from a 420rwhp car? I see cars dyno @ 420 with set X heads where the same heads will dyno 450 on another car with the same basic combo.
Phillip

jmX

I'd imagine dyno's have something to do with it. I've seen a car dyno 442rwhp in houston, then he drove to austin and only makes 424rwhp here.

I'd imagine some of the more common differences are peoples exaust setup. Lots of the big numbers are through a cutout, borla, or something similar (sometimes even open headers).

You should find out what other LS1's dyno at your local dyno, as use that as the scale on the measuring stick.

mike m

iTrader: (6)

if you look there are 2 different cars with absolute speed heads, one with the g5x2 and the other with the th230 cam making over 450 hp. ones in cali and ones in ny. plus there are many others out there. its all about having a set of heads to work with the bigger cams that are now available.

SPANKY LS1

iTrader: (24)

Can someone please explain this to me? Isn't a Dynojet corrected to a "standard", that should eliminate varibles? Isn't SAE horsepower in California the same as SAE horsepower in Texas and Illinois and New York and .....? (Within 1-2 hp, which I could understand)

I mean, isn't a Dynojet a tool to measure horsepower and torque, much in the same way that a grocers scale is made to measure the weight of potatoes? Are we to assume that a pound of potatoes in California would equal a pound and a third of potatoes in Texas, Illinois, and New York?

XFACTOR

I've seen the same thing happen before as well.From what I undersatnd its the way some of the dyno's are setup as far as computer stuff goes (which I really dont know alot about)so this could be the differences we are seeing.Also depends on of its a Dynojet or Mustang Dyno-some shops have the Mustang Dyno and those are calibrated differently from what I here.Its hard to explain but if you ask around Im sure they the different shops can explain it better!!

Slowhawk

iTrader: (12)

It's all in the Dyno's and complete setup of drivetrain.Some people have low hp loss drivetrains which give more HP output on the dyno and some don't.
It's all about the Track time improvements
If your looking for high HP #'s to post just pay the dyno operator some $ and he can inflate the #'s to what you want.

99 Black Bird T/A

iTrader: (4)

I think the key to getting an honest 450+ matching a powerful cam like a 230+ XE-R to a great set of heads, with supporting bolt on's and tuner that knows how to get the most out of the set up with the dyno tune.

If you want an honest 450+ rwhp select the same cam and the same heads that proven set ups have used. Copy what works. I think this also means avoiding certain heads that seem to land cars in the 396rwhp to 412rwhp range. With that said, I think it's very possible the new SAM/Judson 6.0's that TEA will offer will have the best shot of any TEA head for getting into the 450+ range

Also remember that while today the goal everyone wants is 450rwhp with the EWP become common, the bar will be raised and 460+rwhp will become the standard etc.

critter

iTrader: (9)

No, a Dynojet does not measure torque. A Mustang does measure torque. Neither measure horsepower.
Since the Mustang (and other absorption dynos) measure torque directly, you get horsepower by taking torque * rpm / 5252. The Dynojet measures the rate of change (acceleration) of the roller, just like a G-Tech measures acceleration in a moving car. Now, once you have an acceleration value, it seems like you should be able to use the weight of the roller (or car for the G-Tech) and Newton's second law of motion, F=MA to get the force at the tire/roller (or road) interface. Given that and tire/wheel radius, you can compute torque at the axle. Now all you need is rpm to compute horsepower. Simple, right? Except for the fact that you aren't taking losses into account. In the case of the G-Tech, it is rolling resistance and air resistance. Both of those absorb horsepower that will show up on an engine dyno, but no show up as acceleration in the car. It is safe to ignore the horsepower lost in angular acceleration of crank, clutch/flywheel, drive shaft, rear end, and wheels/tires because we want rear wheel horsepower and those (well, plus friction) are what cause the difference in rear wheel and flywheel horsepower. But, using lighter components for those will make it look like you have more power with either a Dynojet or G-Tech, simply because less is lost in the drive train due to angular acceleration. This is the root of some of the "dyno tricks" that get bigger numbers on a Dynojet. Things like aluminum flywheel, aluminum driveshaft, 10 bolt instead of 12 bolt, light wheels/tires, etc are "dyno tricks" that give inflated numbers on a Dynojet. Those components (other than the 10 bolt - friction) would not change the horsepower reading on a Mustang significantly.
I haven't thought much farther than that, but I suspect that the roller mass to car mass ratio needs to be taken into account in the computations. I also suspect that the horsepower level also has to be taken into account.
The bottom line is that a Mustang almost measures horsepower. It measures torque directly and uses a simple computation to get horsepower. The Dynojet infers horsepower by measuring the acceleration of the roller and applying a more complex computation and applying various correction factors to account for the angular acceleration losses.
I guess this is a little long, but I hope it will shed some light on the dyno to dyno differences.

SScam68

iTrader: (20)

Mustangs are a little different. It takes other factors into account like rolling resistance and aerodynamic drag.

There was a great write up comparing a Mustang vs Dynojet vs Real (measured at a track) and the Mustang was almost dead on.

When comparing the curves the dynojet was TOTALLY different than the Mustang!

I forgot what mag did the write up, if I am not mistaking it was Chevy Hi Performance. could be wrong though.

EVIL

phil, come up to heffners and dyno,

i have seen a few high 430 and low 440 cars there with older heads and cam setups.

JPR

Phil99vette,
In our case, it was mainly the combo, I can't elaborate or it will give away the whole secret right now but we are going to mail order with this package soon, I just need a little more R&D time in house for ourselfs.


JMX,
All due respect, in a couple cases I know what your saying, but I was called out by an unamed company to repeat independantly and my customer did within .8 hp 1.2 tq through closed exhaust at a sponsors dyno that we don't get along with. You know who I'm talking about?

Spankey,
The best way to get a more accurate and more level playing feild is using SAE correction, conversly some people swear that you will dyno exactly the same power from 50 degrees to 100 degrees SAE corrected but from what I have seen, I don't believe that to be true.

XFACTOR,
I agree, the callibration on any dyno HAS to be correct, and the weather station must be placed in an area where it won't be falsley infuenced by unstable indoor temp changes.

Slohawk,
I agree that 12 bolts and Furd 9 inch rears with higher numerical gearing will suck up some power on the dyno, but thats why there is a drive train loss calculator, the flywheel power is just reflected more at the rear wheel from a low loss drive train. It's not all about track improvements to some people that don't run there, there just looking for the hardest pull from 55 mph to 140 . I take offence to your last statement though but no biggey.


99blackbird,
I agree 100%, stay tunned for a dyno sheet post on next Friday, a high 470 RWH should be our latest numbers on a new build with our S2 package and will set a new standard here, hydo cam of course with an 800 rpm idle, found more flow .

Evil,
I have dynoed at Heffs shop in the past, nice Vipers everywhere! but we just had a Heff car up here on JD's rollers and read almost 20rwh lower.



JP

JS

iTrader: (4)

Joe makes an interesting point.
Some guys just dont drag race there cars.They want a car that makes good power for a hwy blast or for the stoplight grandprix now and then.

Dont get caught up in dyno # its nonsense,all you'll get is a stomach ache.

There's too many variables and depending on exhaust setups,cutouts,!ps belt,open headers,ewp etc it can vary from shop to shop.Just go with a reputable shop and have fun.

Bearcat Steve

Wouldn'tone of the major varibles be the tuning? For example, you cold easily see two people with the identical cnc'd heads and identical cams (as measured with a cam doctor), but see dramatic differences due to who did the tuning?

I see the parts as introducing a relatively low amount of variance, but the tuning introducing a very high level of variance.

LG Motorsports

We just finished one here today,

A Z06 with our G5x cam package through the LG Pro Long Tube headers with X pipe, stock mufflers full belts, ported TB and pulley.

461rwhp 420 rwtq

We know that our dyno is near 8 to 10 down from another well known vendor because we had one of their cars here this week.
We all know that electric H20 pumps with alternator and open exhaust will get more, but we try to give out numbers the way the person uses the car. If it is a race only car, with open exhaust then so be it. But this car is a daily driver with bolt ons and a stock Corvette Z06 muffler.
We will post up the graph later tonight

Thanks

Lou Gigliotti LG Motorsports

VINCE

iTrader: (1)

You guys are getting some great #'s

99 Black Bird T/A

iTrader: (4)

Lou, were the heads Absolute or LG Motorsports?

460 is amazing, with EWP open exhaust there might be a ~470 in there

The Dragon

iTrader: (6)

jmX

JPR, I wasn't trying to imply the ONLY difference is dynos. I know some combos make a lot more than others, but in the local cases I've seen, the big number guys dyno at one place. When they come to the shop I've used for years, they are sometimes a bit lower. <shrug> In the first dyno, they were dynoing at the shop that sold them the heads/cam, which may have had something to do with it. The local place has nothing to do with LS1's so its pretty unbiased.

I'm always up for trying new combos...I'm already on my 3rd heads/cam combo (and what...my 8th cam?). None of the 3 combos ever put me over 414rwhp here at the local dyno.

LG Motorsports

The heads are Absolute Speed stage 2.5 heads that we had Jay work up for our cams. They have to flow up to .600 CFM while at the same time they MUST stay small to get the Torque up. We have over 400ftlbs of torque from 4400 to 5900 rpms and at 5250 where the tq and hp cross we are seeing 416rwtq and 416 rwhp. Compare the 5250 rpm numbers to the graphs that you have seen.

And it has over 450 rwhp from 6000 until we shut down at 6900 rpms.
Again this is through a stock Z06 muffler.

I am driving the car to bowling Green KY to a Z06 fest to deliver the car to the customer, and I am returning with another one for the same package that is coming from Alabama.


I will post up the graph tomorrow.

LG

jfm

iTrader: (4)

JPR had a customer take his car to another dyno and as he stated it made within 1 or 2 HP.Over 450 in an AUTOMATIC.

Lou made 450+ in Texas[460HP on some] and at Vette Dr in NY an Absolute Speed heads /LG-G5X2 made over 450.

TR 230 cam/Absolute Speed heads on a dyno in California made over 450.

As far as track times I think it all goes to driver skill[M6]and the cars set up overall.I have seen a good driver[Pete/bspz28]run 2 to 4 tenths quicker than the cars owner.With the Autos ,it is a matter of getting a trans to live[JPR knows what I mean],shift points correct,good suspension and tires that will dead hook,the whole A4 race is 60' and 330'.

Absolute Speed Stage 2.5s,I cant wait to see what my car will make with the G5X[2-3-4-?] and those heads.I have a 12 bolt ready to go in and a back up Speed Inc Stage 3 trans,just in case.