vegasredz06

I was at the track about 3 weeks ago, there was a fellow z06 o4 yellow with ati procharger, he dynoed his car that day and got 505rwhp and i dont remeber the torque.hes best run was 12.34 at 117-118 ,yes the track was not preped very well, but the MPH should still be close to rwhp using the HP calculator he should be hitting 124-125 and that's being modest.I also met nother guy with a s/c vette ati claiming 685 rwhp .. hes mph was 122 -- should be way over 131.
I see time and time again, people claiming they are dynoing 500-550-600rwhp and there time dont justifiy the hp.Some of these tuner guys claim this and that and the numbers dont match.
My question to everyone :
How many found that the dynoed number matched the MPH in the 1/4 mile,(the 1/4 time is not that important as you could have traction problems..)

it seems like to me the supercharged vettes dyno numbers are not acurate at all !! (maybe its b/c it peaks for a sec.... i dont really know..

Im just trying to get to the bottom of this....

Turbo-12R

More then likely it's due to the car not hooking up on the track with lots of wheel spin. If the power can't be controlled on the ground it is pretty much useless. Dynos however are a great benchmarking tool.

CJS

Cartek and VetteDoctors Heads and cam cars dyno on some of the same exact dynos at say 450 to near 500 rwhp and have speeds of 120 to 130+ mph.

So the dynos are comparatively accurate car to car.

You bring up a good point though.

The supercharged cars are very difficult to drive in the quarter compared to H&C.

Look at guys like Optic, Z51R, and others, with big supercharged speeds in the quarter.

Everything Depends on driver, gears and tires, and track prep

vegasredz06

even though they dont hook out of the hole, they still have bad MPH,, for me its all about the MPH ,, I ran 125 in the 1/4 and have cars that claim they have 600-700 hp and run 122-124 ..the mPh should still be up there , for example Lingenfelter has on his website a white c5 running only 11.2 ,, but at 137!!! the MPH will still show in the end, and these s/c vette that claim 500+rwhp are not showing up at the track......

Turbo-12R

That makes no sense. The dyno shows just when and where horsepower and torque kick in. If the car is rated at 600 rwhp and is making runs of what any 400 rwhp car can do then it is because of the driver not being able to get the car to hook up...not because there is a flaw of measuring horsepower on a dyno between a naturally aspirated engine and a blown engine. Naturally aspirated engines tend to have a much more linear horsepower and torque curve which makes keeping the power to the ground easier. If you are spinning half way down the track due to the dramatic increase in power then of course you will not get good MPH. The key to solving some of this would be to use a multi-staged boost controller (on a Turbo system).

IGO202

Hey Turbo-12R.....
Just curious about your ZX12R, did Mike Chestnut help you on the installation?
Dan

jak112460

The car will still do the MPH even if it has trouble hooking up. It will hook up.

Turbo-12R

No, I did all the work to the bike myself. My kit on my ZX-12 was fairly mild at only 300 rwhp (compared to some in the 500+ area). Still enough though to wheelie at 120 mph in 6'th gear just by twisting the throttle. Mike is a friend of mine though. In fact, Mike buys most of his parts through my shop.

laron

No........Boost is qite a differnt animal...

Ive been blown.....

The C5 or Z06 that has 50+ rwhp will have an incredible time putting that power to the ground......

You think that just like your NA car with the average 280-315 stock rwhp ......You wil spin off the line.....Resulting in a bad et but still good mph....


thats because once you hook off the initial launch you will then drive the other 99%of the 1/4 just like normal......So your mh will be virtually uneffected....

Th blown car on the othr and thats putting out 500+ rwhp will spin off the line.....

Get taction andgo till he hits second.....Spin again...Slowing him down a bit ....And thn maybe spin again when hitting third gear....

Even thoug he spun 3 times vrs your once off the line his et and mph will still probaly be bettr than yours.....


Supercarged boost is rpm dependent..........

You know how each time your NA car hits a gear change in the a4 or you manualy change gears thcar has that litle kick to it????

Well...In the boosted car from th second he hits 2000-3000 rpms boost is on demand...

Then when he winds out to 6000 rpm's in first gear......The car or the driver changs gears...

For that split second during the gear change the boost goes down to 0.....

Then when the split second is over and the cars back in gear th bost suddenly sends a extra 100-200 rwhp back to the rear wheels.....

resulting in the famous second and third gearr spinning tires........


A good example of this was when I raced a supercharged Z06 last weekend.....

I was expecting to get creamed....

But we launched evenly and he sarted pulling on me through 1 st gear...

He was a good car in front of me and then He changedgars and I saw his car spin again...

My car changed gears lie a normal a4 with no spining ad I dovrigt past him.......

I was two lenghts in frony an I saw his car coming quick....

He pulled right ahead of me wih ease......

Then his car lost tractin AGAIN!!!!!!!!!

I puled n font of him by a lot!!!!!!! I coudnt even him beside me any more....

I ended up wita 13.6 at 102 mph compared to his 14.2 t 110 mph....

This happenned several times....I think his best of the night was a 13.8 or so....

IT TAKES A LOT TO GE THE FULL PERFORMANCE OUTOF A BOOSTED C5.....

THERE NMBERS ARE LEGIT....

UT GETTING TATPOWER TO THEGROUND IS INSANE...

JUST GETTING THE FULL POTENTIAL OF THE STOCK 300 RWHP REQUIERS SLICKS.....

IMAGINE 100-200 MORE RWHP

Dave_Busch

This has been the question for quite some time now. Here are my experiences with this.

First off you do not race the dyno. On the dyno your run is in 4th gear. The dyno pull may take 10 seconds. When you’re on the street or track in first gear, it may be closer to 3 to 4 seconds. Now you have to accelerate the mass of the supercharger in a third of the time, which is not easy to do. A D1SC can take as much as 175HP to turn at 6500RPM’s. When you try and accelerate the supercharger in such a short period of time, it is so much easier to have belt slippage in first gear compared to 4th.

The second problem is tuning. I can not tell you how many times this is the problem.

On the track if every thing is working properly, driver error will show up in ET but the MPH will still be high. I have seen more SC cars at the track with ET streets, they hook fine, shift fine, but don’t Et or MPH.

A SC car is not much harder to drive compared to a head and cam car as long as you have a good set of tires. SC makes boost based on Rpm’s, so when you shift the boost comes rite back. A turbo car on the other hand can be difficult to keep the turbo’s spooled up on the shifts.

Optic’s car is a great example. It makes the HP on the dyno, it traps the correct Mph, and it has the correct Et for the power it has. The belt is not slipping, the car is tuned properly and he has decent traction. He has taken the time to make sure it is set up correctly.

vegasredz06

hey guys thanks for all the input , it makes sense . i guess there is alot of variable, especially s/c cars...

AU N EGL

Dyno numbers dont win races when the cars are close in HP, driving skill does.

Brandin

Also most supercharged cars are susceptible to heat soak.

On the dyno most performance shops will run the car with the hood up with 1-2 fans being pointed at the intake and motor.

Supercharged cars will at times loose 20-80 rwhp between passes depending on coolant temp and iat's.

At times you are stuck in the staging lanes for a long time with the engine idling.

If I was building a race car I would use Nitrous

If I was building a fun street car I would use a supercharger

Brandin
04 C5