Dyno Compare of Stock v Ported Top End

[XfireZ51]

Go example of stock motor and what porting does to performance. Its not just the hp/tq number but the area under the curves and the peak rpms.

[-=Jeff=-]

not just porting, you have headers and exhaust too.. and Don's is all stock right? except maybe exhaust, but don still has OEM manifolds and cats right?

[bobbyhi]

Just had mine dyno'd yesterday at DRM. 385 rwhp and forget what the torque was. I have headers, upper ported, K&N air, and Power Effects exhaust system.

[XfireZ51]

Originally Posted by -=Jeff=-

not just porting, you have headers and exhaust too.. and Don's is all stock right? except maybe exhaust, but don still has OEM manifolds and cats right?

Don's is stock except for catback as far as he knows. Unfortunately, I never got a chance to dyno car with just the addition of the headers or when it was stock so the comparison I presented here was as close as I could get to showing diff between where motor was when I bought it to present trim. If I was to hazard a guess, I would say the porting was responsible for most of the extension of the power and torque peaks and how the drop-off is less dramatic than stock. Jeffvette, Locobob could probably give some more data on that.
The numbers on this dyno were ~ 20hp down from previous dyno. That was true for the other cars being dyno'd at BG as well. The guys running the dyno called it "heartbreaker" because it was conservative.
Dyno run at Street Stuff was 387rwhp, so in line with bobbyhi's numbers
at DRM.

[Paul Workman]

Very impressive, Dom. Thanks for that (submitted to my ZR-1 file).

Like you said, the (huge!) dynamics change affects the entire characteristics of the LT5 (not that they were bad to begin with!). And, the thing about it is, the 32 valve DOHC design allows for this level of improvement w/o sacrificing street driving characteristics; a very tall order for a 16 valve config, apparently.

I have only one question...Where did I put my die grinder!!!

P.

[GrayZ]

here's mine after i got er done

[-=Jeff=-]

Originally Posted by ITLGO2

here's mine after i got er done

Originally Posted by XfireZ51

I would say the porting was responsible for most of the extension of the power and torque peaks and how the drop-off is less dramatic than stock. Jeffvette, Locobob could probably give some more data on that.

The headers are what allow the power level to continue out on a broader section of the curve. The porting and the headers basically work together. I would say individually, they add about 15 hp each, but combine them together and the combo jumps to about 40-45 hp total.

[XfireZ51]

Originally Posted by ITLGO2

here's mine after i got er done

Keith,

This had to be after you guys finished in the parking lot at BG! Nice FLAT torque curve too.

[karterdon]

To answer the questions of my motor that Domenic refers to -
The engine is completely stock with the following exceptions
DRM Chip, Acell injectors, Cat back Flow master exhaust. K & N replacment stock air filter, A/C delco replacement plug wires and NKG Iridum spark plugs. And Oh - by the way - A reman / used A/C Delco Alternator that was replace that Friday in BG - That had to increase HP & Torque by ????? At least $575.00 dollars worth.

Last note - engine has 76,000 miles at time of Dyno.

I am very happy with the HP & Torque results - Even happier that I have approx. 20hp more then what is shown on the chart - since it appears it was a conservative Dyno as Domenic stated. The other three cars were off by approx. 20hp from their previous dynoe tests.

350 RWHP -

Don Yoakem
91-#267
Dark Red Met.