Previous setup: 383 stroker, FLP 1-3/4" headers into 3" true duals into 3" Dynomax Bullets dumped before the axle, 78mm Direct Flo lid.
New setup: 383 stroker, ARH 1-7/8" headers into 3" Y-pipe into 3-1/2" merge into 4" intermediate into 4" Mufflex dumped before the axle, 85mm Fast Toys lid.

Any guesses on how much peak power I picked up? What about area under the curve?

Oh yeah, you might want to know I have a 8" ATI converter that flashes to 5200 rpm. Not the best for big dyno numbers.

 

How much power you picked up? None. I always guess conservatively.

 

I'll guess you picked up 13-16 at the peak.

 

Those ARH Are awesome I say 15-20rwhp

 

Post a graph or ban!

just kidding...but please post a graph. I despise guessing games.

 

 

Sorry guys. I despise guessing games too. Just didn't have the scan available until now so I figured I'd poll the audience.

OK, so here it is...



No surprise here because everything I do to my car gives me either a net loss or no gain. Yes I was dissappointed but not nearly as much as when I spent over $4,000 on 37 extra cubes only to lose 15 rwhp across the entire curve. I swear every time I mod my car I pick up nothing or lose power. BUT, and a big BUT, I somehow end up running a good number at the drag strip... So lets see what it does this weekend. Then I can either cry or brush it off. Big stall unlocked autos are no good for dyno numbers I tell ya.

 

P.S. My car is whisper quiet now compared to the old setup. Yet I don't know if stealthiness is worth $1,400.

 

what's your suspension set-up? including tires...

 

BMR EVERYTHING plus QA1 adjustable shocks. Tires last year were 28 x 9.5 x 15 ET Drags. Tires this year are 28 x 11.5 x 15 Hoosier QTP's. I was hoping the bigger headers and air lid would give me 10 rwhp and 10 rwtq. I was shooting for 10.0X this year. But after seeing how little power I gained, I'll be happy if I go 10.1X.

 

Damn very dissappointed result.

 

Maybe it's not having longer stroke that needs the 1 and 7/8 headers...maybe it's the larger bore in combination?

 

What do I win?

 

i think you will pick up a tenth or so... i picked up 1 tenth and 1mph on back to back runs from the blackwing lid to the new fast toys lid

and the 1 7/8 should help but you have to factor in the weight of your new set up since its a full catback now... well kinda lol

 

This is a 383 stroker. Bore is still 3.905. I was really hoping I'd gain 10 rwhp across the curve. However, my new cam last Fall picked me up only 15 rwhp across the curve but I dropped 3 tenths and picked up 4.5 mph so maybe I will drop a tenth and pick up 1 mph...I hope so anyways.

Also, this exhaust is lighter than my true dual setup. I'd say by 15 pounds. All I have now is y-pipe straight into a 4" Mufflex and a short turn down. Not much to it.

 

Did you try dynoing with no muffler? The whisper quiet new setup could be robbing you some power. I would drop the muffler and redyno.

 

I thought about that but could a 4" straight through muffler really be all that restrictive? I will test it this weekend. I'll make a couple passes with the muffler and then a couple without.

 

damn a whole one Horsepower...lol that sucks! You should def see a quicker ET though, have you ever done a compression/leakdown test on the car?

 

One thing, you are slinging more weight around withe the bigger tire, that may have cost you a couple...

 

I wouldn't waste my time doing this.

I have ARH 1-3/4" with 3" collectors, 3" y pipe w/ cats that then merge into a single 3.5" that connects to a Mufflex 3.5" catback with a Magnaflow and single dump at the rear... I can assure you that your exhaust is just fine...

I re-tuned my car and lost 13whp, yet picked up nearly 4 tenths...

The moral to the story is - STOP DYNO RACING.



Did you re-tune the car after changing the setup?