Dnyo History Comparison

Dalamar · Feb 6, 2007

What do you guys think of the differences here?
I choped and scaled in my 3 different dyno's.

First is - stock with mufflers and CAI, Auto
Second is - ported PI headswap, cams, mufflers, Auto
Third is - Stroker, Ported PI's, cams, mufflers, Manual

Keep in mind that along with the stroker assembly, the compression changed from 10.3:1 to 9:1
and it's changed from an auto to a manual Transmission.

My elevation here is 4200 ft, and these were all loaded dyno pulls
There's more to come, but here's the NA comparisons on my Modualar (so far)

Edit: if your not sure what your looking at, here's the beef

the fat fuzzy lines are stock NPI with mufflers and CAI. sux like a boat ancor. 5 years ago or something.

the thin lines are the dyno after my PI/Cam swap, auto trans
blue is torque, red is HP

the fat color lines are my latest dyno
Stroker, Manual trans ect. - HP (red) and Torque (blue)

What do Y'all think?

<img src="http://www.sn95forums.com/hosting/users/dalamar96/dynocompair.jpg" />

95KBGT · Feb 6, 2007

wow if im reading this right thats some good shiet

FIVELITERS · Feb 6, 2007

Thats pretty neat.

Dalamar · Feb 6, 2007

Thanks KB, thanks 5L

it's interesting how different they are.

ALITL8 · Feb 6, 2007

Dalamar said:
it's interesting how different they are.

by different do you mean the way the torque curve drops off faster with the new set up? what gears are you running? your numbers are definitely better but i was expecting more... especially in the torque curve. looks like with your last set up you made solid, steady torque all the way up to 5K before it started falling off. now you hit peak torque at 4K and then it immediately starts falling off :dunno:

i like the new numbers by the way. when are you going to the track?

DropTopPony · Feb 6, 2007

ALITL8 said:
Dalamar said:

it's interesting how different they are.

Click to expand...

by different do you mean the way the torque curve drops off faster with the new set up? what gears are you running? your numbers are definitely better but i was expecting more... especially in the torque curve. looks like with your last set up you made solid, steady torque all the way up to 5K before it started falling off. now you hit peak torque at 4K and then it immediately starts falling off :dunno:

i like the new numbers by the way. when are you going to the track?

from the results and research i have seen done on strokers on 4.6's this is typical. The piston come out of the bore way too much at BDC and they actually wabble and become unsteady...Thats one of the reasons you will never hear get a stroker on a 4.6 come out of my mouth. I considered it a few years ago but after talking to a few guys who raced modulars over on Modular Depot and then seeing test results the Tymesky's (modular performance) posted on Corral a few years ago (stroker vs big bore) i just came to the conclusion that it will give you a small boost in TQ down low but you will be hindered in the HP and higher rpm TQ #'s and you see it on Dal's dyno. I was told go Big Bore or stay at 281-284 ci by a builder who sells stroker kits all day long. Modulars already have all the stroke you need...we need more bore.

DropTopPony · Feb 6, 2007

Oh let me add this so it doesn't seem like i'm bashing Dal, his combo was built for Turbo so while his compression isn't low its not what most NA cars are at and he would certainly have better numbers if he was @ 10.0 CR...and these strokers seem to respond well to FI and since Dal is going the Turbo route he will be making big power down low and not have to wind that thing out to 6500rpm's to make power so his ride will be sick!

Dalamar · Feb 6, 2007

That's interesting, thanks for the replys.

I hear what your saying DT, but I still think the Bore vs Stroke is hyped up.
I think this is a pretty good gain in torque in the lower RPM's, which is what I wanted.
It does fade off on the higher rpms compared to before.
I don't know exactly why, but I don't think it's piston wobble.
I've heard from a number of sources that - that first test everyone likes to talk about was on some POS stroker parts.

In the picture of the bottom of my longblock, you can see the first piston at BDC, and it's not far out of the bore.
:dunno:

I'm not done yet boys, this was just the first tune on a brand new motor.
thanks for the feedback.

Edit - that's correct DT, thanks for unbashing me

Dalamar · Feb 6, 2007

The compression is a big difference.
on the PI before, it was 10.3:1
the after dyno is 9:1 compression.

Do you think maybe on reason the torque fades is that it's not getting enough fuel?
it's still pushing the stock 19#ers - woot

Lightning Struck · Feb 6, 2007

Dalamar said:
The compression is a big difference.
on the PI before, it was 10.3:1
the after dyno is 9:1 compression.

Do you think maybe on reason the torque fades is that it's not getting enough fuel?
it's still pushing the stock 19#ers - woot

Hmmm they really drop there after the 5 grand mark, I would think a inadequate fuel system would definitely hurt.......but those numbers really go on the decline

could the fuel hurt THAT MUCH??

ALITL8 · Feb 6, 2007

damn if i know... something to talk to the tuner about though. like Jeff said, this is the first tune on a fresh build... could all be in the tune.

uncltrvlnmatt · Feb 6, 2007

DropTop has some interesting thoughts on piston wobble at BTC, but IMO if it the piston were to wobble enough to make the torque and HP curve drop that much that quick, that engine would vibrate violently and self destruct. Like I said that is my opinion.

If you have a bored, stroked, cammed, ported, PI set up, you need to give that bitch some fuel. Those stock injectors and fuel pump won't keep up. You need to feed it same as anything else.

It would be like installing a 2bbl carb on a HiPo 289, it is going to starve for fuel.

I would talk to your engine builder, or a tech support line and get some pump and injector recommendations.

Dalamar · Feb 6, 2007

thanks for your input, I will be talking with my tuner on it.

It could just be the Compression difference and fuel ?

ryclef331 · Feb 7, 2007

Your HP numbers stayed up there.... Your TQ dropped.

You gotta remember that with an auto, a torque converter provides TORQUE MULTIPLICATION so that number will be high. I would say that you're giving up some power with those injectors BUT your tq loss can ALSO be attributed to the switch from an Auto to a Manual.

Dyno's are great for tuning and bragging rights but the TRACK is where its AT. THATS the Before and After that MATTERS!

Dalamar · Feb 7, 2007

Roger that Ryclef, thanks for you input.

I dont know the exact reason, it's probably attributed by a number of factors.
I'll do some asking and more tuning

compression
fuel injector size
Torque convertor - Auto/Manyal swap
longer stroke

Does the flywheel have anything to do with it?
the stock wan was small, and the new one weighs like 30# or something.
It's a beefy SOB.

Thanks for the feedback everyone.