how much HP

[vettestr]

Originally Posted by Flyin_Freddie

Horsepower's a little like sex...

...if a little is good....a lot's GOT to be better...!

Horsepower is sex !
I would much rather die from too much than die from not enough.

[scootter]

You might think you don't need much till someone pulls away from you like you are standing still. You just need to get use to it and be careful doing it. I have over 550rwhp. Wouldn't trade it for anything!!!!!!
Scott

[GlynMeek]

Originally Posted by maxum_101

just wondering if 550 hp from a roush 427r is over kill for a spf .

hmmmm..."overkill"...interesting superlative, but never really heard it applied to a Cobra?

[STL Mark]

Yep - overkill - go for it - might as well get the 588 from Roush - that's overkill - and well worth it. Just about the same money as the small block 427. Get the most HP your wallet can afford.

Just my .02

[maxum_101]

the reason i ask about the poly mounts is due to reading here that some members had an issue with the headers hitting the body, dont want to spend all this cash to have the headers hitting the body cause of a few hundred bucks for other mounts,

as for the larger sway bars from olthoff (sorry if if not spelled right) what does something like that cost?

and 1 more thing there was an issue going around with the brakes and the roush engine not having enough vac or something i tried searching for the thread but no luck does anyone know if there was a correction for this issue?

[Excaliber]

Big horse power is nice, but STREERABILITY is nicer! You will be traction limited at some point. Keep the compression within the 'pump gas' range and the cam profile should match your expected cruising rpm, speed. Those are the two keys to maximize enjoyment on the street.

[speed220mph]

I have 575 hp from my FE 427 and, well, I would like more! See below:

[Red S/C]

One of the posts here suggests you'll lose between 35% and 45% flywheel to rear wheel horse power. Those figures are considerably higher than anything we've seen in the race cars we have built.

[BLUE427]

Maxum101.....

Get The Poly Mounts, I Just Put Them On For That Reason And Like Them Alot, Stops Alot Of Driveline Vibration Also.
Brakes Are Fine, Swaybars Might Be A Upgrade, I Havent Done That Yet, I Have A Roush 427, And Like It Very Much.

Blue427

[Cobra #3170]

Originally Posted by Red S/C

One of the posts here suggests you'll lose between 35% and 45% flywheel to rear wheel horse power. Those figures are considerably higher than anything we've seen in the race cars we have built.

Absolutely right, I have seen between 15 and 17% loss depending on the transmission make and drive line configuration. The major reason for low rear wheel numbers is that the engine never made the claimed HP at the flywheel.

[392cobra]

Originally Posted by Red S/C

One of the posts here suggests you'll lose between 35% and 45% flywheel to rear wheel horse power. Those figures are considerably higher than anything we've seen in the race cars we have built.

Stock/standard exhausts will drive the losses up that high.

You can't expect to get good rwhp numbers with low losses from the crank without a special effort put into the exhaust.

[Cobra #3170]

Originally Posted by 392cobra

Stock/standard exhausts will drive the losses up that high.

You can't expect to get good rwhp numbers with low losses from the crank without a special effort put into the exhaust.

If you don't dyno with the equivalent or entire vehicle exhaust system you are not going to get accurate in-car results and a correct tune. I know that is difficult but not impossible especially with the outside systems used. I have dynoed all my engines this way and it translates well to rear wheel numbers IE 15 to 17% loss. The fuel air ratios, cam timing and ignition timing are also much closer to ideal. You could also do most of the tuning on a chassis dyno but changing cam timing can be a challenge in the chassis.

[aa4v]

I recently had my BDR Roush 402SR/TW/TK0600 on the Dyno at Performance Engineering. The dyno run that came with the engine from Roush showed 486 HP/487 TQ (at the flywheel). The PE dyno run showed 394 HP/383 TQ at the wheels.

[jdean]

Powerful brakes are good too to go along with the HP and speed....dont forget about those.

[Got the Bug]

aa4v - I've got the same set-up in my SPF, so that gives me a pretty good idea of what my HP and TQ is at the rear wheels. Thanks for posting that.

[Red S/C]

aa4v - those numbers would be very close to the numbers we have seen. The engine (533 dual 750's) I currently have did 696 hp and when we do the chassis dyno we're looking for around 570 to 580. Sidepipes and headers are a big part of it. We used 2" pipes on the headers and 4" on the sidepipes with the spiral inserts which we had great success with in the past.

[FUNFER2]

Maxum 101 (and others)

I'm wanting more power also. Currently, with this engine, I have 400 @ the wheels. So, the numbers I have in mind is apx. 550 to the ground or 600 + at the flywheel. What I would like to bring to attention on this thread is, yes, high HP/TQ is just plain kick in the pants fun, and like I said, wanting more.

But, how much do we want to suffer in gas mileage vs the power we crave ?

I get apx. between 10-16 mpg city/hwy, depending on how much fun I have with the throttle.

With you guys having the 482 cu. or so, and having say,....500 + RWHP, how is your mileage ? (please be honest)

If it drops down to 8 mpg, I would have more serious thinking to do.

Maxum 101- have you thought about this issue too ?

[Nantucket427]

MPG what is that? The EPA sticker must have been lost in transit. I have never even tried to determine it. Will it stop me from going somewhere? No. I try to find away to take the car everwhere I need to go. My wife said I even make stuff up so I can take the car. I own a replicate because I want to drive it. I don't own an original to look at, I want the full experience. I am surly not worry about operating cost.

[Silverback51]

Originally Posted by Nantucket427

MPG what is that? The EPA sticker must have been lost in transit. I have never even tried to determine it. Will it stop me from going somewhere? No. I try to find away to take the car everwhere I need to go. My wife said I even make stuff up so I can take the car. I own a replicate because I want to drive it. I don't own an original to look at, I want the full experience. I am surly not worry about operating cost.

Well said.

[FUNFER2]

I do agree. Six other cars and I went to Kansas and back on the Hot Rod Power Tour. When we were planning on going, we all agreed to not worry about gas prices, and have a @hit load of fun, and we did. It was a blast and were going next year.

Come on guys, it has matter to at some point, especially with todays cost of gas.

What would you rather do, stay home and save up money for a while because your cobra gets 8 mpg and sit there wishing you could drive it or go anytime you want because you get say,...15 mpg.

If I still had my Pro-Street Camaro, I would not even think, about driving as much as I do the Cobra. It actually did get 8 mpg. That's one, reason I sold it to build the cobra.

(out of curiosity, what does your 462 get, honestly) ?

Like I said, at some point, you have to say,.....enuff z enuff.