how much HP

maxum_101 · #1 (**permalink**) 08-13-2008, 03:03 PM

just wondering if 550 hp from a roush 427r is over kill for a spf . i know its a stroker and not a bb, but for the weight of the car is it really needed? is it streetable or do you have to watch your ever move and not hit the gas to hard in a take off. would say 450hp be a better choice? or how about an alum block with less hp, it would the lower weight and be better in the front end.

just looking for some input and what combo you are running, example running a roush 427r with a tko 600.. whats your final drive on the tranny? is it good on the hwy what are the rpms at say at 85mph

any info and input would be great

thanks in advance

sgianino · #2 (**permalink**) 08-13-2008, 03:35 PM

Go for the 550! We all know that the true rear wheel horse power will be around 300 on a rear wheel Dyno. I can attest to that being my car was around 650 @ Crank and produced 415 @ the wheels.Heres a link to the Dyno shop we used for the testing, they give greater detail of the Dyno details

http://www.ktrperformance.com/dyno_t...ter_graphs.htm

Great Asp · #3 (**permalink**) 08-13-2008, 03:50 PM

get the horsepower.

If scared at first, place a 2x4 under the "wow" pedal.

E

RodKnock · #4 (**permalink**) 08-13-2008, 04:08 PM

You can always install a throttle stop. "More power Scotty." If there's enough money in the budget, then go with the aluminum block too.

puppster · #5 (**permalink**) 08-13-2008, 04:50 PM

I think that 200 horsepower is plenty, in a light weight machine like a Lotus Elise. There's oppertunity to get in trouble if you're really driving it hard. But if I was just cruising in it and didn't have a desire to go around turns... I don't think it get's any better than 500+ horsepower in a 2500lb car. You can't help but respect it. I think it depends on your personal desires.

HI Cobra · #6 (**permalink**) 08-13-2008, 05:12 PM

Keep in mind that traction is the limitation in lower gears, not the hp.
However, with these cars, more seems to always be better

. 20%-25% is
a reasonable benchmark for hp loss from crank to rear wheels. What you
plan on doing with the car - cruising or tracking - also is a determiner.
Now it is up to you! Have fun. As far as rpms go, that depends on your rear
end ratio. If you will be cruising then the 5 speed with the od will help that.
A little research for YOUR specific needs will give you those answers.

MFE III · #7 (**permalink**) 08-13-2008, 05:36 PM

I'm with everyone here . . . go for the HP. I'm running a 427w, 550 hp and 560 tq and althought I'm only in the go-karting stage, I can tell you that the power is auxilarating!!! A littel daunting at first, but you'll get used to it. As far as streetability, I think it's fine.
I'm running 3.55 rear gears and the TKO with the .82 5th. Most prefer the .82 5th gear ratio over the .64.
Here's a good gearing calculator:
http://http://www.5speedtransmission...alculator.html
Good luck and have fun!
Matt

Randy Rosenberg · #8 (**permalink**) 08-13-2008, 05:41 PM

If you install less HP now and if you want more later, then it can get very expensive. Better to invest once, then have to re-do later.

alpace@pacificp · #9 (**permalink**) 08-13-2008, 06:03 PM

I've posted my Dyno sheet from Keith Craft in my gallery. I love it. Plenty of 'oomph', but very, very drivable. Controllable Machismo!

al

native1 · #10 (**permalink**) 08-13-2008, 06:49 PM

I have the roush 427 sr tw with 450 rwhp. Thats well over 500 at the crank. Probably close to 540. I AM LOOKING FOR MORE!!! Get as many ponies as you can afford. I love my roush it is very street friendly. If you want to be The Man try the 427ir. Hope this helps.

maxum_101 · #11 (**permalink**) 08-13-2008, 07:22 PM

thanks for all the input and info, now heres a few more questions if you all dont mind,

the steel flywheel that comes standard on the roush is it better to upgrade to the alum unit?

also factory spf motor and trany mounts, is it a good idea to upgrade to poly mounts or to a solid mount?

and this item selling on ebay

http://cgi.ebay.com/ebaymotors/Super...mZ110257493981

is something like this worth the money, will it improve the overall drive and handling of the car as compared to the stock pieces

thanks again to all who take the time to post.... it is a big help

Stentor · #12 (**permalink**) 08-13-2008, 07:25 PM

Quote:

Originally Posted by native1

If you want to be The Man try the 427ir. Hope this helps.

No, if you want to be "The Man" step up to a big block!

And if you really want to be "Da Man" step up to an aluminum bored and stroked big block!

Madmiles442 · #13 (**permalink**) 08-13-2008, 07:31 PM

Go with more HP.
Solid mounts will shake your teeth out.
I've had poly but prefer the standard rubber. Then I put a bolt through them to limit movement. But the vibration dampening is so much better.
I don't know Voss. I put the Olthoff sway bars and poly bushings and it makes a HUGE difference in handling!
Just my $.02

Slick61 · #14 (**permalink**) 08-13-2008, 09:03 PM

Quote:

Originally Posted by Madmiles442

Solid mounts will shake your teeth out.

...pish... I've got a KCR aluminum 427w in my Backdraft with solid mounts... it's not bad at all. The only time it's really noticeable is at idle. Mine puts out approx. 612 hp/tq at the crank & 458 hp/tq at the wheels. With the aluminum flywheel, it spools up fast... almost faster than you can shift (my TKO-600 does not like to be speed-shifted)- so you learn quickly to go easy on the loud pedal in the first few gears. The pucker factor comes into play when you open up the secondaries... yee ha!

Got the Bug · #15 (**permalink**) 08-13-2008, 09:24 PM

I've driven an SPF with and without solid engine mounts and the difference is barely noticeable. I haveThe Olthoff engine mounts in my SPF and they've been great so far.

Same experience with the TKO 600 as Slick61. I went with the Steeda shifter, but the second to third gear shift still takes some time to get used to.

Like everyone says, if you got the dough go for the HP and don't look back.

scootter · #16 (**permalink**) 08-13-2008, 10:17 PM

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 · #17 (**permalink**) 08-13-2008, 10:20 PM

Quote:

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 · #18 (**permalink**) 08-13-2008, 11:00 PM

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 · #19 (**permalink**) 08-14-2008, 07:18 AM

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?

Nantucket427 · #20 (**permalink**) 08-14-2008, 07:40 AM

The car is a handful and I would suggest high performance drivng school no matter how much horse power but isn't that what is all about? We all want the bragging rights of a big block with over 600hp. I am always mused by how many people run up to me and tell me they make over 500 hp. I would like to put them on my dyno.
I drive mine slower on the street because I don't have to prove anything. I respect it and am learning how to handle it better everyday. Anyone can burn rubber but can they go sideways at will with out wrecking something.

You must learn how to control the "Force" Young Skwalker.