A comparison between MPI & Push

[Yamadog]

I found this over on Hardcore sledder

"Track dyno numbers are 117hp on pump fuel and 12lbs boost. 141 hp on race fuel and 18lbs boost. Push turbo, .090 head shim, larger injectors. Was able to get 115.8 mph in 1000' with less than ideal ice conditions "

After the clutching and the 4th injector on my MPI turbo at 12#'s of boost my track HP is almost 144. So these are not getting the same HP/# of boost increases that we were told. at the track I am getting 28 more HP at the same boost #'s. which means crank HP on the push is 201 to my 252. And I am getting more HP at 12#'s with a blend of pump and race fuel 7.5 gallons pump and 2.5 of race to their 10 gallons of pure race gas at 18#'s of boost.

 

[tapex_07]

I don't feel like this is an apples to apples comparo.... It's cool your making big power, but your taking about a built and very well setup sled vs a head shimmed and we don't know anything about it sled.

 

[Yamadog]

This was a sled built and posted by speedwerx. The only diff is they have a head shim and I have low compression Wiseco pistons (which made more sense after the motor blew because I had to replace the pistons anyway) with the same compression as the head shim. He has oversized injectors I have stock injectors with a 4th in the intercooler. Only other diff is they clutched it and Ulmer clutched mine.

 

[tapex_07]

I didnt know it was built by Speedwerx.

Definitely makes sense to do the pistons while you had it apart, but the comp ratios are not the same shim vs LCPistons

 

[TD Max]

The key to racing dynos is not to do it in the first place. A dyno is a very useful tool, but numbers can vary widely from dyno to dyno. The key is to look at the before and after from same sled on same dyno and look at the net gain rather than the whole numbers.

 

[Riceburner]

I saw that too. Made no sense to me.
12 psi of boost has to be worth more than 65 ish hp at the crank.
My MCX Apex is double that at 12 PSI on pump fuel & it is head shimmed.
Push Turbo can not be that inefficient can it?
Either that, or their drive train is very inefficient & or the Dyno's are very different.

 

[Yamadog]

The key to racing dynos is not to do it in the first place. A dyno is a very useful tool, but numbers can vary widely from dyno to dyno. The key is to look at the before and after from same sled on same dyno and look at the net gain rather than the whole numbers.

Well in a nut shell that has been my problem with all of this since day one. Kit builders calling their kits 190 kits I guess they mean its a # not a HP #. Some are claiming 190 at low elevation on pump gas with no intercooler, Stock injectors and no head shim. Even Read that there is a Push 240 kit that runs on pump gas 87 octane with a head shim!!! Without pulling timing I don't know how that is possible.

And I know dynos are different but 24% that is a wide variation in HP #'s. You would think a speed shop would want their dyno close to true hp.

 

[Riceburner]

Interesting to see the Turbo Lag differential between your Viper & my Apex.

The Turbo dyno run track HP exceeds the stock dyno run at 16 mph or so on your Viper vs my rear mount MCX 290 was 35 MPH before boosted HP was greater than stock.

Half the lag is a good thing.

 

[Yamadog]

Yes there is almost no lag on these. The Blue run is not the stock curve, that is 7#'s of boost the red one is 12#'s. This sled had a turbo on it from new and was never dyno'd prior to install.

The conversion is 1.75 x 143.65 = 251.39 crank HP at 12#'s of boost
1.75 x 113.03 = 197.81 crank HP at 7#'s of boost

Both are very close to 9.7 hp / lb of boost

The trottle response on this thing is instant and the power from 3000 rpms to rev limiter is mind blowing. I had an rx-1 with a rear mount Bender system years ago and could count to 3 before it went balistic.

 

[4kops]

Riceburner I think I may be able to comment on the difference my viper with hurricanes 400 kit which is set at 14 lbs do boost on 91 or 93 octane which is like 270 ish is still behind your apex set the way you bought it. I will say after getting some bugs out that where totally my fault and with help from Dave my viper is as close to driver friendly as I have seen my old nytro with Ulmers turbo on it set to 210 ish was awesome to drive very friendly and linear power that fricking old apex of mine that you bought was almost darn right sick to drive that thing came on like a freight train and was viloent. Talking to Dave he says his 240 kit has a better throttle response can't wait to get that on my new xtx Le

 

[turbo800]

Well in a nut shell that has been my problem with all of this since day one. Kit builders calling their kits 190 kits I guess they mean its a # not a HP #. Some are claiming 190 at low elevation on pump gas with no intercooler, Stock injectors and no head shim. Even Read that there is a Push 240 kit that runs on pump gas 87 octane with a head shim!!! Without pulling timing I don't know how that is possible.

And I know dynos are different but 24% that is a wide variation in HP #'s. You would think a speed shop would want their dyno close to true hp.

Yes, MCXpress has a 270 kit that is shimmed and runs around 17psi boost and runs on pump 91.
I don't know for sure, but I think they would have to pull some timing to make it live at that level...

17psi x 9.7hp per lb = 164.9 boost hp

165hp plus 130ish base hp = 295 HP!!


I think MCX even did a few 310 kit for the Nytro, but I don't know their details

 

[MrSled]

The key to racing dynos is not to do it in the first place. A dyno is a very useful tool, but numbers can vary widely from dyno to dyno. The key is to look at the before and after from same sled on same dyno and look at the net gain rather than the whole numbers.

OMG... finally. Thank you!!

 

[Yamadog]

OMG... finally. Thank you!!

I was not racing dynos, I am trying to figure out how some kits are making 190 hp at 6#'s without intercoolers. Or making bigger HP without fuel pump upgrades or running 87 octane. I am running 9 most of the time but to run 12 with low comp pistons & need my octane to be over 95??? I was merely pointing out that the different setups, which are infinite, can and do produce different results.

 

[cannondale27]

When a dyno chart is posted without rpm all credibility with me is lost. Useless chart.

 

[MrSled]

I was not racing dynos, I am trying to figure out how some kits are making 190 hp at 6#'s without intercoolers. Or making bigger HP without fuel pump upgrades or running 87 octane. I am running 9 most of the time but to run 12 with low comp pistons & need my octane to be over 95??? I was merely pointing out that the different setups, which are infinite, can and do produce different results.

It was not directed at you it was in general..... did I quote you?? NO but u should know more then most.. you cant ride a dyno and just like the sleds everyone is a little different and inconsistent. If you purchase aftermarket based on dyno number then it could be your loss... you need a stock run to at least see and compare the outcome from a baseline.