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500+hp street club
I would be interested in hearing from folks with a 500+ hp street machine.
1. Overheating problems 2. Idle problems 3. Drivablity issues 4. Traction issues I am ready to roll with my 408 stroker, I have lived with 351W and 385hp, what should I expect with the extra power. |
I am running a R-block 347 stroker with twin T04e turbos. Dynoed at 535 rwhp and 585 rwtq at 9 psi.
Some people say that the R blocks don't stay cool on the street due to the siamese bore but I haven't had any problems. Mine runs around 180-190. (180 stat) No idle problems. Driveability issues? Only the one listed below. Traction can be a problem. I have 275/40-17" Nitto drag radials on the rear. Yes in 1st gear, and in 2nd when the boost comes on. The Nittos really work well though - better than any other tire I have tried. I just try not to do anything stupid and always make sure it is pointed straight before getting on it. The 17" wheels are not period correct but then again neither is that big 4" thick intercooler standing straight up in front of the radiator.:D Mike |
overheating ++ HP
I live in Phoenix and I had my toy out for a spin today in 105 degrees. I have spent many hours and many many things to make toys run in this heat and still live but it takes a lot of effort. Mine is 542 inches with all the goodies, it does create its own set of issues to overcome because it is 13.4 C/R and the tach will almost keep up with the fuel gage. I would not have it any other way but be ready for the following. I buy fuel by the drum at $5.20 a gallon because Circle K is not an option. I have to trailer it to many of the club runs if very far. It does load up if idles very long like a parade. It did require a lot of special work to live and not overheat in the Phx. heat and none of that was cheap either. I do have to be careful when playing on a windy road etc.. as it looses traction and will spin end for end at the worst time if you are not right on top of things always.
If you want to just play and not have to work on it or trailer to many events stick with the pump gas model with a little extra bang ( copy a late 60's version). The HP to weight ratio of a Cobra in stock engine form is still pretty damn good. That is not my thing because enough is never enough for me but it does come at a price. |
1. 500hp shouldn't require massive compression to achieve. I don't believe you should ever have incurable overheating problems in any pump gas small block Cobra.
2&3. No problems - just use a quality engine managment system 4. Common sense, a little restraint and some Nittos. :3DSMILE: |
No problem for me
I think the fact that I have aluminum heads, and stainless steel headers might keep the motor cooler than normal.
I would assume any modern motor over 500 ponies would have aluminum heads anyway. The SS headers keep the motor cool, but the engine compartment is hotter than my old SPF. My water temp is 190 f, with the fans kicking on at 200 f. Oil temp is almost too cool at 158 - 170 "most of the time". However if I run it hard for 15 minutes, oil temps shoot up to 210 f max, but quickly cools off (no oil cooler hooked up at this time). I don't think heat is much of a problem at lower compression (10:1 or so). I would think the boosted engine would have more of a chance of heat trouble, but he is doing fine too. Eric |
What Eric said above. He has more horsepower than I do but I am running 11-1 compression. A left over from when I was having the motor built for 600+ horsepower and changed my mind. I have never had any type of heating problem and when I can stand the heat I have driven mine in the 115 degree Summer humid heat we get here. Traction: no problem. Just don't use 1st or 2nd gear with very much throttle until you get used to it.
Ron**) |
On the overheating problem, I refer you to a previous post of mine from the Arizona Cobras forum:
http://www.clubcobra.com/forums/show...light=radiator My car, with the stroker S/O, aluminum Edelbrock heads, Crane cam and dual 600 cfm Holleys, idles just fine, thank you. Starting is easy, even with the chokes removed from both carbs. Key it, let the electric fuel pump fill up the float bowls, pump it twice and it starts on the second revolution. I usually have to play with it for about 30 seconds, but then it settles down to a 900 rpm idle. This procedure works in temps from 110 down to 40. Drivability is no problem, unless I get caught in l-o-o-n-n-g traffic stops; then the plugs will start to foul up. Other than that, the only real problem is the noise from the sidepipes. Traction is always an issue when running the kind of torque these cars have. When you start pushing 500+ ft-lbs to the pavement under a 2500 lb car sitting on street tires, traction control becomes a concern. Judicial application of the go-pedal and attendance at a driving course will help alleviate the attendant problems. |
Everything seems cooler at 100 mph.. my car idles fine at 850.. Traction?? I thought that was a snow driving skill.. Although I will say I do get pretty good grip now that I put the 315's on the back..
What exactly is a drivability issue? It's a Cobra..:LOL: |
502hp at 5600 rpm
504 lbs/torque at 4600 rpm. Idle: about 800 rpm Starts quick once fuel bowls fill. Average running temp 180 degree F. No overheating problems. Twin pushers kick in at about 185 f. No traction problems. docile as a puttycat below 3000 rpms. Once on the cam it kicks in pretty hard though. |
606 hp @ 6100, 418 stroker fed with pump gas, Idles good to fair,
temp stays between 150 and 160, as far as traction goes i have to take it easy on the throtle ( due to the 572 ft lb of torque ) but it's pretty managable on the street best thing about it is it scares the *^$^ out of the mustang streeters. |
I suppose my little motor "might" fit within this thread, but I won't admit to it just in case insurance companies are watching.:3DSMILE:
Fresno has been over 100F for the past several days. I've been doing some high temp "testing"--stop and go for several miles each late afternoon. With 800 miles, the 10 to 1, pretty radically cammed beast runs at about 180-185F. Runs on 91 octane just fine and starts very easily--cold or warm. I've got the idle at about 1000--I'll probably lower it a bit. Drivability is just fine. Haven't completely floored it yet. I'm actually a bit intimidated by this beast and I don't mind saying so. I'm not gonna talk traction while I still have regular 15" tires on it. I intend to destroy the rear ones at the Fling and put on a set of Hoosier TDs when I get home to finish off the autocross season and do some stuff at Willow Springs and Buttonwillow. |
WE WILL NOT DESTROY ANYTHING AT THE FLING! !:3DSMILE:
You do know I am sitting here with a tear in my eye. With only a dyno proven 427.0 HP at the rear wheels, I don't belong! :mad: DV...gonna have to do something about that |
Where you messure the HP
O.K. we have all talked about 500+hp. The question is where you are measuring it. A true measure is on the DYNO. However 427HP at the rear wheels is 508 hp at the flywheel if you use 18% drive train loss. Most crate motor spec are at the flywheel. I started this thread asking about the experience of going from 385hp to 500hp. My number is calculated using desktop DYNO, its the place you start when you are picking components for you new motor. I would love to here from folks that built a motor with a calculated flywheel HP number and then what happened on the dyno.
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peterd:
My answers in order: 1. None 2. None 3. None, except cops in my rearview. 4. Oh, HELL YES! :LOL: Robert |
peterd
I feel worse(r :D ) than DV. All I got is 412RWHP through a C6. Works great in rush hour DC traffic, and in "rush hour" traffic at Summit Point :LOL: :LOL: No complaints here - nothing but grins :MECOOL: Tom |
both test results
Motor dyno was a peak 556 hp
While my best chassis dyno has been 435 hp (RWHP) Eric |
Asp...that is 78.24% or 22% drivetrain loss.
Just curious.......What tranny are you running ? |
Been out of town...sorry
Jam,
Yeah, I hear ya on the % of loss. The motor dyno was without sidepipes. The chassis dyno is as the car runs on the street, that is I have not tried to get the maximum out of it on the chassis dyno. I have the car a little more rich than the motor dyno, I retarded the timing slightly, the sidepipes are on (of course), IRS rear end, 3550 tremac, and I did not inflate the tires from their normal 20 psi. So I don't know. Maybe I should try for maximum run? Eric :MECOOL: |
This is a good thread, and I haven't bought an engine yet, so I could still go with a stroker. But the one question PeterD didn't ask about was oil consumption. When I think of little bitty short pistons being driven on the street (meaning a lot more miles than a show car) I can't help but wonder about ring wear. Anybody have any firsthand experience with a stroker that has some miles on it? How long will a stroker last before it starts burning oil and making the sidepipes messy?
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A stroker should not wear rings. All engines are "strokers" A 428 is a stroker 390. A 460 is a stroker 429. A 350 Chevy is a stroker 327. etc. If you have not built many engines get with a rep. builder and buy a complete unit. They have usually experimented with many combinations that can produce big,reliable power thats easily streetable.
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