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Stroker gain HP on same boost level?

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usmc0651dns

10+ Year Contributor
209
1
Jun 3, 2010
Monticello, Kentucky
Theoretically, when I got my engine built and went from 2.0 to 2.3 liters, would I gain horsepower on the same boost? The built motor also included cams, pistons, etc.
 
Is there anyway to estimate? Just hoping for an average increase before I drive 2 hours for a dyno. Thanks.
 
Yes for more HP.

For how much more HP; that is a question best asked in the bench racing thread.
 
All bolt ons are the same as before. The only change was building the motor. Compcams 101200 (258 exhaust, 259 intake), AEM TruTime cam gears, Forged pistons with H beam rods, and port / polish, decked head. Not sure on the compression and good ole' pump 93 octane. Probably not enough information. I thought maybe there would be an estimated gain from going stock 4G63 2.0 to built 2.3L. I figured it would be pretty complicated for a close estimate, just excited to see some gain over the previous 330 WHP.
 
Well, you gained 300cc, which is 15% more displacement, so you can expect a 15% increase in torque, but becuase the engines airflow demand is increased, the rpm that the torque is produced at will be lower. So, expect a 10% increase in power.
 
Last edited by a moderator:
Sweet. Maybe I'll feel a bit hairy and bump the boost up for the next dyno. Thanks everyone.
 
I have the same setup as you do, and to tell you the truth yes there is a little bit of hp gain but is not as noticeable as you'd think, it does make your turbo spool faster tho,mine is a tdo5 20g and the spool up time was where i noticed the most difference.
 
Yes for more HP.

For how much more HP; that is a question best asked in the bench racing thread.

This is the best answer. I know Maurice knows the math and is too lazy to explain, so here goes:

Engine volume flow (CFM) = (CIDxRPM)/(2*1728)

Going from 122 to 140 cubic inches is indeed a 15% increase. The equation for mass airflow is

[P(psia)*V(cfm)*29]/[10.73*T(R)] * VE

While you do incease V, you can't guarantee that all the other variables will be equal (especially VE)--thus there is no way to say how much more power.
 
The answer to this question is very simple, just solve this equation; 2.3L - 5x^-2y^104z^1000 over 2x^-1(-3x^-3y^-1)^-2(-6x^-5y^-1)^-6z^-2y^144x @ whatever boost level you are running = the added hp from a stroked 4g63.

If you have trouble with that you can just wait for your dyno results LOL
 
Actually I had calculus as a Sophomore in high school so that does put thinks in perspective. I wasn't aware that there was a definitive equation for that floating around. I figured there were a few more variables though ROFL.

Ummm, what do I substitute for X, Y, and Z again? :ohdamn:
 
No math here, but I have a 2.3 stroker with 9.5 compression, head work & balance shafts removed. Other than that it in BONE STOCK. Stock boost level, stock ic piping, 2g blow off valve....etc as I said "stock".

I can say however from the old seat of the pants dyno. It's a lot more "purky" now. Spool on the stock 2g turbo is instant. So I would say all the math is correct, it is a noticeable increase. Not sure if its a number worth spending cash on a dyno run but that's up to you.

P.S. Welcome to the stroker world! :thumb:
 
The answer to this question is very simple, just solve this equation; 2.3L - 5x^-2y^104z^1000 over 2x^-1(-3x^-3y^-1)^-2(-6x^-5y^-1)^-6z^-2y^144x @ whatever boost level you are running = the added hp from a stroked 4g63.

If you have trouble with that you can just wait for your dyno results LOL

This just made me laugh till I cried seriously your killing me!!!!!!:cry:
 
My calculator couldn't handle all those exponential variables. Anyone have an extra graphing calculator? I think I used a TI-82 back in the day for such equations. Can't wait for the new dyno results to see if the engine build and my new decals make a difference.
 
those decals should net at least 5 whp for ya :thumb:

Seriously, remember that you will have more hp earlier by being able to spool the turbo sooner and therefore, more tq at lower rpms. Since tq and hp is just a ratio based on rpms, your hp peek may or may not go up depending on revs. Being able to maintain tq at higher rpms will increase hp and even with your mods, it is just a guess.

can definately say that you may lose power depending on tune. You have changed your engine geometry and will have to change your tune to get the most out of it. over all, the car will be faster with a good tune as you will increase the area under the curve.
 
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