Forced Induction 97 Cobra Project With Kb 2.6

KillerCobra97

New Member
Dec 18, 2014
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Jesup, GA
Okay first off i'm a new member so i'll do my best to ask these questions without confusing anyone

I have a 97 Cobra i want to build from the ground up, it runs perfectly now but i got in back in Feb for $6,500 with 65k miles on it i haven't done anything to it yet it already has headers,CAI and a few other things. but im looking to get about 600RWHP out of this thing when im done. I want to keep the motor i don't want to do a TERMI swap and money is not an issue here. I want to do everything the right way the first time and down time is not a problem but this will but a street car in the end when it is done.

I want to supercharger it so im going with an entire forged bottom and i figured while i was there i might as well get the stroker kit http://www.modmaxracing.com/product_p/99025450.htm but my question is would i get more power out of a stroker than stock once i add the blower?

Kenne bell doesn't make an inter-cooled kit for the 96-98 cobra.. so i would like to know if i put a pair of C heads off of a 03-04 cobra but would the 2.6 kb on fit my car with those heads (i know there will need to be some customizing done) but the 2.6 comes inter-cooled and it makes much more horse power.
http://www.kennebell.net/KBWebsite/SC_pg/Cobra (96-98)/layouts/mustangcobra4.6.htm
http://www.kennebell.net/KBWebsite/SC_pg/Cobra 4.6/layouts/cobra4.6.htm

What cams would you suggest with the C heads? (keep in mind the s/c)

Im wanting to run 3.73s..i don't think ill be able to hook if i go with 4.10s
also i need to address traction, ill be putting sub-frame connector and a trac rebuild kit with some good street radials. Any Brand suggestions?

I wouldn't mind upgrading to a T-56 but i don't want to do any cutting on my frame, how hard would that be?
but im pretty content with a good built T-45 http://www.thet45source.com/transmissions.php im going with the strongest one they have.. does anyone know of a better tranny source?

i have a King Cobra clutch still in the box.. will it be enough for this set up?

these are the main things i need feed back on also i plan on doing a lot more things like.. steeda short throw,high flow water pump, high volume oil pump, front/rear WilWood brake systems, light weight racing flywheel, etc

PLEASE GIVE ME SOME FEED BACK PEOPLE!!!! HELP A BROTHER OUT!!
 
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I was under the impression that you can fit KB intercooler under the supercharger, in the valley of your existing engine without changing the heads. May need to call KB about that though. I'm a 2V guy and don't know for sure.

You might make a little more hp or tq with a stroker but in all the articles I have read its never made too much a difference. If you were buying a short block, why not have a few more cubes otherwise your paying more for the added cylinder boring at the machine shop. Your overall compression (under vacuum and boost), boost levels and your heads/cams will probably be the main deciding factor on your power levels. I'm also not sure how well the Teksid blocks do with cylinder boring. I believe that's an aluminum block with steel sleeves. I can't really help you with the heads questions. Don't know a thing about their differences.

As for the trans, most people do the T56 swap or go to the Tremecs. I would do whatever is most cost effective. I'm not going to mess around with my 3650 when it goes. I'm opting for the Tremec. I don't think a king cobra clutch will hold 600
hp/tq to the wheels.

My buddies 98 Cobra puts down just under 500 hp to the wheels. He has 4.10 gears with a centri blower. First and second gears are usually just tire spinners when he gasses it hard, even with drag radials. I wouldn't go any higher than 3.73 and might consider 3.55s.

I'm a 2V owner and someone may jump on here and tell you everything I have just said is wrong. But hopefully there's something in this that will help you on your way. Be mindful of mod fever. Its a real thing and will drain your bank accounts.
 
My recommendation. For a built supercharged motor, be careful with stroking.

I would also recommend not doing too much (if anything with cams). Instead focus on building a motor with the CR ratios what will allow the supercharger to make the power.

Choose the CR based upon if this motor will be inter-cooled or not.

+1 on above regarding gears. Let the supercharger make the torque for you.

Basically remember that gears, cams, and stroking are tricks used by NA engine builders to get more out of a NA setup. If starting out with a SC set up, then the combinations should be picked to allow the SC to make the power.

My recommendation!!!! Call KB and tell them what your HP goals are and ask for their recommendations and be prepared to follow them. KB has the necessary experience and knowledge to get the job done. Resist the urge to "roll your own" without the know how to back it up.

Good luck.
 
As long as you are comfortable with the cost that is going into this build....then go for it.

1) To stroke or not to stroke. I wrote a dissertation on this in college, so I have done a bit of research. There are 3 ways to look at the engine. Square, oversquare, or undersquare. Square engines have a similar bore-to-stroke ratio, effectively 1:1. These are good, reliable engines. They have a good tradeoff of torque and power. This is why you see 95% of cars produced have a square or near square (slight undersquare) engines. Oversquare engines are engines that have a larger bore vs stroke. This is usually seen in diesel, truck, and marine engines. They are very efficient torque producers at low RPMs. Undersquare engines have a longer stroke vs the bore.....aka, strokers. These engines are usually high-horsepower race engines, capable of higher RPMs. Formula 1 cars have something like a .42:1 bore/stroke ratio and spin to 16k+ RPMs. Indy cars are in the .72:1 range spinning to 10k-12k RPMs, and NASCARs are .78:1 bore/stroke ratio topping out at 10k RPMs.

Cost considerations vary for the engines as well. Square engines are just that, square and boring. They usually don't need a lot of special parts, and just decent forged bottom will allow for 6k rpms, and decent power. An oversquare engine is the cheapest. Since they do not spin near as fast, some sacrifices can be made in connecting rods and piston material. If it will be supercharged, that will need to go into the considerations for stress on the rods (pressure), and piston material to resist detonation. Undersquare engines are by far, the most expensive. Because of the higher rotational speeds, special, lightweight but super strong pistons must be used. The rods will almost always be billet aluminum, or possibly forged titanium. These are not cheap. As a design component, like in F1 car, the rods are titanium, and long...almost the length of a stock 4.6 rod. The crankshaft however, is small, only providing like 43mm of stroke.

To put this into relative terms for the Mustang, and modular engines for that fact, the 4.6 modular engine is pretty darn close to square. Stroking it make is undersquare, and boring it makes it oversquare. Boring the 4.6 is limited due to spacing between bores, and if you have an aluminum block, it limits it more. Expensive sleeves also hamper aluminum blocks that require high boost. If you want more bore, the easy way to get it is the BOSS 5.0 block. It starts life oversquare with a larger bore than stroke 94mm(3.700") bore (90.2mm[3.552"] for the 4.6), and a 90mm stroke (3.542") giving the engine a 1.04:1 squareness. If you want it back pretty close to square, stroke it. This will make the cylinders 94mm (3.700") and the stoke is upped to 95.25mm (3.750"). This makes the engine undersquare to .98:1. The BOSS block has slightly longer sleeves to prevent pistons from coming out of the cylinders, so a little extra RPM and stroke won't hurt.

Now that you have read all of that, I wouldn't stroke a 4.6 for any reason. Not because of the square vs. undersquare stuff, but because the cylinder walls are too short, exposing the piston skirts causing excessive piston slap. I also prefer a more square engine. That is why I DID stroke my 5.0 BOSS block to 5.3L.

2) Cams. Get blower specific cams! Blower cams usually have lower overlap to reduce the amount of fuel mixture being pushed out through the open exhaust valve by the pressurized intake charge during the intake stroke. They compensate for the resulting lower duration by having higher overall lift and more aggressive profiles. Blower cams usually improve power, drivability, emissions, and fuel economy on S/C cars.

3) Transmission. The T-56 can be installed on a 97 Cobra without cutting anything. D&D Performance makes kits with the proper driveshaft and braces. I went with the T-56 Magnum and love it. I went with the 2.66 first gear, but with stage 3 blower cams, it can be tricky off the line during normal driving.

4) Clutch. If you are not worried about price, look at the SPEC Twin disk clutches. I have one that holds 1200 ft/lb of torque. It is actually easier to drive than the stock clutch without the grabbiness of some higher tier single disk clutches. It ain't cheap tho, but it does include an aluminum flywheel.

5) The blower. Well, here is what sucks. You would need quite a few things to make the 03/04 Cobra blower work. Heads, lower manifold, crank pulley, blower pulley brackets and mounts. Alternator relocation parts.....I could keep this list going forever. Is it possible, yes! I put an 03/04 whipple on my 2v, so I know a lot of the crap that you are going to need, how hard some of it is to find, and how expensive some of it is. The easy way would be to find the entire front drive assembly of an 03/04 cobra engine. From there, you have options from Kenne Bell to Whipple to Eaton TVS's.

5) Worth it? Yes and no. If I had the $30k back I put into my build, I would sell the car and buy a Shelby GT350 with the 5.2L VooDoo flat plane engine. Will I complain with what I have, NO. 700+rwhp that I can use as a daily driver is fun. I did most of the work, so that is something rewarding to look back on. In the end, it is a 2003 GT regardless of what I did to it, or how much money I put into it. I had the money, and I did what I wanted.......but I don't know if I would do it again. I say that, I am picking up a 1994 Dodge Stealth RT/TT next week....

Just my $0.02..... take it for what it is worth to YOU!