mourat

Before anyone asks, yes this is with methanol single stage and I had a few runs in there but cut her off as soon as I hit 740rwhp.

Car runs with and without methanol thanks to Dave's flex module.

Cam is still ZR1 and heads are GMPP LS3 untouched (they come CNC ported from GM), blower kit is A&A with flip drive.

Dyno is a Dynapack Hub Dyno and numbers are SAE corrected. I'm running a 3.4 pulley on the S-trim and stock size balancer on the crank (ATI).

What would something like this run for MPH at the track if traction is not an issue?

C U IN REARVEIW

Very stout.....! I've been thinking about going straight to a 3.4" vs a 3.6" pulley....but I'm stock bottom Ls2 so.....?

schpenxel

Headers?

What correction factor?

How much boost were you seeing?

SpeedyWs6

Can you give any details about how you use the flex fuel box with the meth?

schpenxel

He's already made a thread on how to do it. Basically it's a relay triggered off of the LED going green that turns the flex fuel tricker box "on" which makes alcohol % go to 100% on the ECM.

jleews6

A few years ago my friend went 137 with his ls2 car with an ECS kit on 9 pounds and 640 RWHP. This was on Nittos and driving it about as easy as you could possibly drive a 6 speed car at the track. The car would have easily gone 140 if he drove it harder.
I would have to think your car should trap in the mid 140s with 100 more HP.

Ant-Man

3.4" pulley is like 13-14psi? Here I was thinking about running a 3.3" pulley on a ysi..

neverstop

in for results when you take it to the track and find out!

curious on afr and timing? how do IATs look?

Unreal

Looks like a dynapak not a dynojet. Either way good numbers.

mourat

3.4" pulley I'm only getting 10 PSI. Mods are as follows -

GMPP LS3 heads (stock bottom end)
LS9 cam w/PRC springs good to 650 lift
Meth
IAT's at 9*C with meth ON
Air fuel is at 11.3:1
timing about 17*
Texas Speed 1 7/8th headers with stock Z06 axle back

Can't wait to hit the track

This is a Hub dyno (Dynapack)

As for Dynojet 248 vs Dynapack. Dynojet 248 is useless, you can put as much timing as you want and not see any pinging and get a high number. As soon as you go to the track you're pulling 10* of timing because now you're loading the engine.

Dynapack you can set it to take say 7 seconds to complete the run regardless of power, this way you're simulating real track actual time you spend in 4th gear loaded. So all the sudden all you can do is 8-9* of timing off meth. On the Dynojet 248 I get away with 14* off meth.

Methanol I don't seem to have any issues with timing at all but haven't tried dynoing with Meth on Dynojet chassis dyno. That being said, I get higher numbers on the Dynojet 248 chassis dyno than I do on the dynapack, and most of the loss comes from the dynapack loading the engine and only getting away with 9* of timing tops before seeing knock with dynapack. I want to tune the car the way it runs at the track, so I don't use the 248 anymore.

Thread -
https://www.corvetteforum.com/forums...s-dynojet.html

Here is a vid of the two dyno -

Unreal

Dynojet is a brand
Dynapack is a brand

Saying a Dynojet Hub Dynapack is like saying a Coke Cola Pepsi.

Dynojets can have load control, or not. Depends on the model, and if the operator turns it on.

I'm a hyge fan of Dynapacks, but saying it is a dynojet is just flat out wrong.

mourat

Wow I was always under the impression that Dynojet built dynapack OMG wow. You know one of those moments when you realize that you were living under a rock?

I just had one of those moments lol!

I just edited the post for two reasons -

1. My stupidity
2. Preventative measure from stupidity wearing off onto others LOL

This is embarrassing on so many levels.

JasonCzerak

Weird., my car is tuned on a 248 and runs with other cars making comparable power on the street that were tuned elsewhere or on the street. Never knew N/A or S/C gassers to have problems tuning on inertia dyno's. Diesel's on the other hand are very difficult to get tuned right on an inertia dyno and can have incorrect numbers if the dyno isn't operated perfectly.

mourat

The problem with those dynos is that without load, you can get a high number, go to the track and have KR all over the place because your engine is under higher load and spends a longer time throughout the RPM range.

On a dynapack, you load the engine for whatever time you want, this gives you a better idea of where you can be with your fueling and timing.

The other part is when you take longer on the dyno to make a full pass, you get higher numbers because all the sudden the rotational weight doesn't make as much of a difference like gear ratios, flywheel weight etc.. However, you loose power because you can't get away with high timing numbers and low fueling, but you get a better tune for the track.

curtisb23

soo???? lol

JasonCzerak

I've never had KR on my car that was tuned on a dyno jet 248h. I've never had my car at the track yet tho, but on the street, it's making good pulls in 3rd - 5th.

Regarding my old truck/diesel. I have run my own truck on a 248h and then turned around went to another dyno (dyno dynamics load cell) make within 10whp of the same number and same curve then gone to the track and the calculated mph <-> whp was with in reason for the average under the curve from the dyno's. I'm not talking stock truck power numbers, this was in my mid 700whp day's.

So as I said, dyno operator has a lot to do with properly loading and running a car on the dyno to get expected results, load or inertia or whatnot. There's nothing wrong with an inertia if you do it right. If you have a 4000# roller and a 3500#car it's accurate if your a good tuner and have a clue.

Unreal

Any decent tuner should know to back off timing from a non-loaded dynojet vs street.

schpenxel

I prefer to add 8* and let the knock sensors figure it out, pistons be damned

chpmnsws6

Knock sensors are the first thing I desensitize.

schpenxel

Just turn them off, no more knock!