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Too Much/Enough
Byron,
You may or not remember me, I had a lot of trouble cooling my 557, you offered a number of solutions. My engine had 650+HP and definetly had the pucker factor...:eek: With the cooling issue and the afore mentioned, I decided to rebuild it. I still wanted the big block, so stuck with the 428 starting point, when finished (almost) it will be a 514 with a mild cam:). It will be, as most big blocks are, a torque monster, which is what really makes us go. Unfortunatley what sells cars is HP what makes them go is Torque. Hopefully none of us are racing on the street as we know that is illegal, but even more so, when the HP starts taking over, we are above 90-100MPH, another pucker factor :eek: in a go cart type vechile. (pardon the go cart reference I couldnt think of anything else to get the point across). I think most of us love to DRIVE these cars and on occasion punch them out. They key is figuring out what you really want to do. You can spin the tires with a 302. And keep in mind the first 2 questions we are asked, is it real? and what's under the hood, 427? (two other selling points) |
How did you remedy the cooling issue if you did?
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Coling issue
I rebuilt it...And I hope it works (it isnt finished yet)
I tried Water Wetter, New fan (bigger puller, more cfm, better shroud), burping the system (looking for air bubles), I was about to try a bigger water pump, when instead I rebuilt the motor and still changed the pump. I ran an electric mezeire 35gpm, now I have the 55gpm. My problem really seemd to be an air flow issue, standing still it would heat up, but if I got it moving it would cool down. |
I started with a Roush 427R having 561 HP at the crank. The way Superformance was doing the exhaust and fuel delivery at the time in 2005 when the car was put together it ended up producing a touch over 400 at the wheels. I changed the headers, side pipes, fuel line, carb and air cleaner and it put down about 475 at the wheels. I did also change to the aluminum flywheel, near solid motor mounts and stronger half shafts too. With the rear Mickey Thompson ET street drag radials in the 275/60 15 size it worked pretty good. I could see having another 100 wheel HP for kicks and still have the car managable.
I know quite a few guys with highly modified exotic cars. The Cobra with 475 at the wheels is pretty quick. There's very little on the road that would be quicker to 100 mph, but those drag radials are critical to use in my opinion. |
I have a Keith Craft 351W/427 aluminum block (554 hp, over 580 ft-lbs at the flywheel). I have the 3.44 (3.46?) rear and TKO600 with .82 OD. Rear tire size is 275/40R18. Once I added vacuum advance to smooth out the low end the streetability improved quite a bit (as well as fuel economy). Idles at 900/1000. No problem cruising in 5th at 1400 RPM. Gets ~9 MPG around town and 15 MPG on the highway (both if I'm not hot-footing it). Uses 91 octane gas. Since the engine was installed I haven't had it tuned at all - plan to put it on a chassis dyno for that sometime soon (I had O2 sensor bungs installed in the exhaust sysem). I'm expecting RWHP in the high 300s and probably a bit more performance (both low and high end after a pro gets into the 780 cfm QuickFuel carb - vacuum secondaries). Like someone earlier said the excitement ratchets up a noticeable notch when the secondaries open up. And I'm quite happy with the streetability.
Matt |
Matt,
On the chassis dyno, I think you're expected HP is a little low. This equation is for the "Mustang" chassis dyno of 28%. (Dynojet is apx. 8-10 %) The apx. loss is around 28 %, with a manual gear box. 554 HP (-) 28% = 398 Assuming,.... your motor needs more fuel, and proper tunning on the distributor & fuel, it should be over 400 RWHP. |
I use a Ford 460 BB. The output at the crank is 740 at 5000 rpm. Torque is 680 ft pds at 1420 to 4150, in a flat line. On the dyno at the rear wheels, it's down to 620 HP. I use an Aurburn Ratchet spool, non- hydrolic Kevlar clutch, TKO 600, with 0.82 fifth gear. The finals are 3.08. The cars' weight is 2250 with me in it. 2050 in fifth, is 63 mph. 2500 rpm in fifth get 78 mph. 85 mph is 3150. I have been told that at 157 mph, I will turn 5500 rpm. Motor is a custom build, by a flat track racer. The cost was way over 30,000 for the motor. Does it go with 315 R35 17's? What do you think? CDN COPR
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Quote:
Matt |
hp loss in a Cobra
I asked Keith Craft about hp loss in Cobras. He told me he had dyno'ed motors and then installed them into Cobras, then did a chassis dyno. The average loss was 20%.
Dwight |
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