spina74

iTrader: (12)

I've since changed my setup to a less radical one but I'm still curious about the dyno results and why. My friend and I both had ms4's in our cars with slightly different setups but almost identical results. My car had the 6.0 his had the LS1. Below are the mods for both motors. Also, both cars were dyno tuned at the same place and same tuner. My questions is do you think my exhaust held me back.

LS1: Stock cubes/bottom end
stock 241's
LS6 intake, 80mm tb
MS4 cam, 7.400 pushrods
42lb injectors
TSP 2" primary headers
TSP true duals
racetronix fp
Results: 409rwhp, 383rwtq

6.0: Stock cubes, forged internals
stock 243's
LS6 intake, 80mm tb
MS4 cam, 7.400 pushrods
42lb injectors
Kooks 1 3/4 primary headers
Kooks y(crappy merge) GMMG catback
racetronix fp
Results: 409rwhp, 399rwtq

Like I said earlier I went to a less radical setup, smaller cam and 317's for boost, but I'm soon installing my EPP blower cam so hopefully I'll be back in the 400hp range. I've also upgraded to 1 7/8 headers and true duals. I'm just asking because it's something I've been trying to figure out.

HCI2000SS

iTrader: (2)

Hmmm....that is weird. What does you tuner say?

spina74

iTrader: (12)

I never asked him. We tuned on different days so we didn't have an immediate comparison.

redtan

iTrader: (5)

He has 2" primaries vs. your 1 3/4s.

Also, what is the 6.0's compression vs his?

Did you get them dyno'd on the same day at the same time?

What is the drivetrain behind the engine? Tranny...rear end...axles...wheels/tires?

That all can make a difference in the dyno results.

redbird555

iTrader: (14)

I think the exhaust def held you back. The cam and ls motor in general love big headers. Also the weather on both days could have been different. Are you both 6 speeds or autos and what rear is in each car. All the little things by themselves dont really make a difference minus the exhaust, but add them all up and theres your answer most likely

fastvet

iTrader: (2)

I'm assuming both had same rear and Trans with similar weather. Only thing I think that could had affected that was your 1 3/4 vs his 2" headers. Not to mention he has true duals vs your y-pipe. Anything else could be octane that both of u all were using. Idk. It's a good question.

spina74

iTrader: (12)

I'm not sure what my compression was but his was stock ls1 cr. he went when it was cooler out but it's a climate controlled shop and i went during a low 80's day. Drivetrain is the same t56 and a 3.42 10 bolt.

slowswb

iTrader: (5)

The headers are holding back alot of power on that 6.0

fastvet

iTrader: (2)

On the dyno graphs, did u reach peak power first? Or was it on par with ur friends?

30th t/a

iTrader: (51)

The exhaust is definately holding back power. Stock 243s on a 6.0 is 10.9:1 CR (exact same as a LS2 6.0)
Id like to see an overlay dyno chart of each car. I would think the 6.0 would have a much better low & mid range power.

5.3LJimmy

iTrader: (10)

He says the 6.0 is stock cube with forged internals. The pistons will have at some valve reliefs and most likely are dished. Lower compression, smaller headers, and warmer weather are all factors here. The 6.0 did make 16 more foot pounds of torque though.

thunderstruck507

iTrader: (18)

Could be a lot of things, but it sounds like you are expecting the cubes to make up for the power and that's not usually the case from what I've seen. Given the same cam/intake/etc the bigger motor will make more torque but similar power just at a lower RPM.

That's why personally I wouldn't trade for the iron block unless it was a bigger cube stroker with a more aggressive cam/head setup to take advantage of the bigger engine (the exception being stock engine is blown and the block is trashed)

randydry

I'm assuming both had same rear and Trans with similar weather. Only thing I think that could had affected that was your 1 3/4 vs his 2" headers. ....

PewterZCar

iTrader: (2)

My epp blower cam made 422 rwhp 392 rwtq with stock injectors, ls6 heads, ls6 intake, long tubes (1"3/4), a lid w/ k&n, t56 trans, stock 3.42 gears.

my tuner regularly tunes ms4 cars that make 440's through a 6 speed with your mods. I'll be interested to see your dyno with your EPP cam. It may be worth contacting my tuner if our numbers vary significantly.

71 chevy

iTrader: (18)

^ need to know this. being that you made more torque,im going to guess your power peaked earlier?

spina74

iTrader: (12)

Ill compare them if I can find my sheet. I can remember where I put it.

I hoping im not too much behind you. You have the advantage of more CR.

nwforever

iTrader: (4)

That just explained why i have an LQ9 now.

Exhaust definitely could have robbed some power. Im assuming you have dished pistons? That could rob a few HP too because of lower compression.

You have to remember that the dyno is just a tool. My 98' in my sig dyno'd 405rwhp (granted its an auto). But a real test would be a race between you two, especially if you have really close race weights.

JakeFusion

iTrader: (7)

One important distinction. The 243s outflow the 241s. Even with the bigger engine, he should both put out more power AND peak higher due to improved cfm of the heads. Martin showed that in another thread, but basic VE calculations show that as well.

Means the exhaust is the likely culprit. And also variation car to car.

lemons12

iTrader: (71)

Cams that size need compression to run to the potential they can.

The Kooks Y isn't helping at all.

spina74

iTrader: (12)

Well, I got my car retuned on the blower cam. My MS4 made 409 on a dynojet, my 228 cam made 373 on a dynojet. Now with the same heads just a switch to the blower cam I made 405 on a mustang dyno.