Dyno Sheet - HP and Torque Question

vipertocobra · #1 (**permalink**) 11-30-2009, 10:58 AM

we have almost identical cars...I love my 427sr/tw.... How do you like the nittos??

Jimbocobra · #2 (**permalink**) 11-30-2009, 01:46 PM

native1,
No problem hijacking the post - even though I have DYNO ENVY, you indirectly may have answered something that I asked in another post. Is the only difference the side pipes between the red and blue on the second page of you dyno sheet only due to the change in pipes - without other modifications? I did notice they were not done on the same day. I have been trying to get accurate information on how much hp is lost with the BDR pipes. If you have 570 gross hp and you are picking up 15-20hp (I'll split the diff and say 18hp), then the stock Backdraft pipe lose about 3% to 3.5%. Does that sound right to you?
In my case, with 450hp, I'd net 13hp, seems like an expensive way to pick up power. Your thoughts?

native1 · #3 (**permalink**) 11-30-2009, 04:57 PM

Quote:

Originally Posted by Jimbocobra

native1,
No problem hijacking the post - even though I have DYNO ENVY, you indirectly may have answered something that I asked in another post. Is the only difference the side pipes between the red and blue on the second page of you dyno sheet only due to the change in pipes - without other modifications? I did notice they were not done on the same day. I have been trying to get accurate information on how much hp is lost with the BDR pipes. If you have 570 gross hp and you are picking up 15-20hp (I'll split the diff and say 18hp), then the stock Backdraft pipe lose about 3% to 3.5%. Does that sound right to you?
In my case, with 450hp, I'd net 13hp, seems like an expensive way to pick up power. Your thoughts?

Yes, that is correct. The second dyno sheet is the difference between the stock BDR pipes and the new ones. No other modifications were done in between the 2 dyno pulls. I was trying to find out for myself...

The side pipes are not totally custom. I simply ordered new glass packs from Stainless Specialities and had them welded in place of the restrictive BDR glass packs. I am sure you have looked inside your pipes and noticed that the exhaust is routed between 2 small pipes inside the glass packs. The new glass packs are straight through. The project cost me around 800 bucks in the end. I could notice the improvement through the seat of my pants. It also sounds so much better. It sounds a lot deeper but not a lot louder.

Just another note. I tried a different air filter "bigger" with the pleats on the top of the filter. I did it in between pulls for an experiment... Picked up 9hp at the wheels. I don't run that filter because I don't like the way it looks but I thought that was a lot for only an air filter.... "first dyno sheet"

Also I have read that Mustang dyno's are not as optimistic as the Dyno Jet dyno's... So don't feal too bad.

Jimbocobra · #4 (**permalink**) 12-01-2009, 01:09 PM

That is great information on the stock Backdraft sidepipes, thanks for posting it. I was looking at Roush's site and it looked like your engine is rated at 515hp, but if your putting out 470+hp at the rear wheels, so you must be close to 560hp. Do you know what the rated hp is on your engine?
Funny you mention the air cleaner top, I just picked one to put on when I go drag racing this spring. My aircleaner has a polished aluminum top, but sits below the hood scoop, so the air passes over rather than straight into the aircleaner, I think it will help get a bit more power. Right now, the AFR heads and cam + labor I am going to add will set me back $3,000. I should pick up about 75 hp, putting me in the 525hp to 535hp range. I'll post the new dynosheet then, maybe I can close the gap a bit (for a lot less than a new Roush).

vipertocobra · #5 (**permalink**) 12-01-2009, 01:17 PM

His increase in power is from the 950 carb, Intake and pipes....Thats where im headed next !!

petegtsv10 · #6 (**permalink**) 12-13-2009, 09:16 AM

Quote:

Originally Posted by Jimbocobra

native1,
No problem hijacking the post - even though I have DYNO ENVY, you indirectly may have answered something that I asked in another post. Is the only difference the side pipes between the red and blue on the second page of you dyno sheet only due to the change in pipes - without other modifications? I did notice they were not done on the same day. I have been trying to get accurate information on how much hp is lost with the BDR pipes. If you have 570 gross hp and you are picking up 15-20hp (I'll split the diff and say 18hp), then the stock Backdraft pipe lose about 3% to 3.5%. Does that sound right to you?
In my case, with 450hp, I'd net 13hp, seems like an expensive way to pick up power. Your thoughts?

Jim,
While my engine is at Clayton's, I've taken on the project of making sure my exhaust is NOT the weak-link when the mods are done. (AFR225 heads and solid roller cam) After many forum searches and many houre of long distance phone calls, here's what I'm doing:
2" custom equal-length (32") headers into a real 3.5" merge collector. That will taper into a 3" (22" long) ClassicChambered CobraPack muffler. It will look almost like the FFR pipe when it's done, but flow and scavenging will no longer be a question. And, as a bonus, I'll have my FFR sidepipes and headers to sell and I'll have a much deeper tone.