Mo' Powa

[AtomicLabMonkey]

Check this out.. I think I'm gonna install this setup on the Mustang once I get it back.

http://www.cnlperformance.com/76mm_94-95cobra.html

I was thinking about swapping out the rear-end gear soon, but I may wait on that now cause it'd end up being like $1000 once it was all said and done. This'll bump up the power output a notch for a lot cheaper than it would cost to re-gear it. With this and the new intake manifold (when I finally get it on... I need to bug Ehren about fabbing up that strut-tower brace) I think it'll really scoot.

[sperry]

Yeah, the T-Bird guys have ben swapping in Lightning MAFs with good success for a while now. That'll prolly give you 5-15hp, but most of it top end. You're still gonna need that gearing for autocross acceleration. Gearing will also help you to take advantage of the top end.

I'm surprised the rear-end costs $1000!? When I was looking for the T-Bird, a LSD was under $400, and installation supposedly is a breeze, like only an hour of work (at a shop)! Other T-Bird guy were getting them done for under $600... and if they did the swap themselves... for like half that!

[AtomicLabMonkey]

Originally Posted by sperry

Yeah, the T-Bird guys have ben swapping in Lightning MAFs with good success for a while now. That'll prolly give you 5-15hp, but most of it top end. You're still gonna need that gearing for autocross acceleration. Gearing will also help you to take advantage of the top end.

I'm surprised the rear-end costs $1000!? When I was looking for the T-Bird, a LSD was under $400, and installation supposedly is a breeze, like only an hour of work (at a shop)! Other T-Bird guy were getting them done for under $600... and if they did the swap themselves... for like half that!

I know, I didn't think it would be anywhere near what I'm finding, but I'm getting quotes from different shops here in the bay for like 4-5 hrs worth of labor.. so it's not just one overpriced shop. So the ring & pinion gears themselves are like $140-180, a rebuild kit for bearings & seals ~ $180 (which is a good idea since it's got 95,000mi+ now and I don't think the rear end has ever been touched for maintenance), plus who knows how effective the limited-slip diff. still is, it probably needs to be rebuilt. The guys at Mike's shop were telling me that the Ford traction-lok diff. doesn't hold up very long under hard auto-x use, so if I take the rear-end apart it's a good idea to just replace it with an Eaton posi-trac, they hold up under hard use and are still fine for the street. So all the parts and labor would be around $1000. Suck. I still want to do it but I'll have to put that off for a while I think and hope my differential doesn't give out on me soon. It's holding up well for now at least, I can usually nail the gas coming out of corners and the rear end stays planted.

On the plus side, the dyno curves that I've seen for the C&L MAF units from multiple sources all look good, it's a fairly static torque/hp gain through the RPM range, no loss of torque down low even on stock 5.0s. I didn't think the MAF would make much of a difference at first glance, but you can't really argue with valid dyno numbers. 5hp here, 10hp there, pretty soon you're up near 300.

[sperry]

Speaking of 300hp... I should get my re-mapped UniChip back from Vishnu tomorrow.. and according to the dyno tests on other WRX's I should be putting out 300-320hp!



That's for Stage 1, but I've also got the intercooler hoses, which dyno'd +5 to 10 hp. So, basically, I should be putting 220hp to the wheels, or more, at least down at sea-level. Up here in Reno, I prolly lose like 20hp... but I can prolly run 16 or 17psi safely to make up for the lower oxygen.

The only place to go from here is upgraded fuel delivery and turbo/intercooler... and since I'm not planning on going that far, I'm pretty much done w/ power mods! Unless I decided to migrate my engine management to EcuTeck for a smoother power curve, or to UTEC for user tunability....

[sperry]

Hey Austin... another idea:

What about ganking an entire rear-end out of a wrecked truck or something? Are there any older vehicles that have the gearing you're looking for? Like an '88 F-150 or something? Who knows...

[AtomicLabMonkey]

Originally Posted by sperry

but I can prolly run 16 or 17psi safely to make up for the lower oxygen.

Exactly... basically you shouldn't lose any power at all with your car at altitude vs. sea level since you can adjust the amount of boost... you can turn it up to compensate for the loss of air and be back to exactly the same air density/pressure entering the engine as you would have at sea level. Mine on the other hand... even if I advance the timing to try to get some power back it will still never have the same power output as sea level.

[AtomicLabMonkey]

Originally Posted by sperry

Hey Austin... another idea:

What about ganking an entire rear-end out of a wrecked truck or something? Are there any older vehicles that have the gearing you're looking for? Like an '88 F-150 or something? Who knows...

Well I'm not too hot on the idea of getting used gears, if they've got a lot of miles on them they can be noisy since they're set in a wear pattern from a different rear end. And changing the entire rear end, like the whole differential, means replacing the whole axle cause I don't think the axle tube/differential assembly comes apart. And that's a shite-load more labor cost

[sperry]

Originally Posted by AtomicLabMonkey

Exactly... basically you shouldn't lose any power at all with your car at altitude vs. sea level since you can adjust the amount of boost... you can turn it up to compensate for the loss of air and be back to exactly the same air density/pressure entering the engine as you would have at sea level. Mine on the other hand... even if I advance the timing to try to get some power back it will still never have the same power output as sea level.

Almost... I can compensate, but there's no way to increase the ppm of 02... I still have to run a higher pressure to get the same amount of oxygen, and higher pressure is harder on the motor.

Think of it this way... at sea level I have X amount of O2 at 15psi. At 4200 feet, I have .8X O2 at 15psi. If I go up to 17psi, now I'm back to X O2, but the motor's running under higher pressure. Basically same, power, more wear.

Also, I'm not sure how the ECU will react to 17psi all the time...

The big issue is knowing how much I can turn the boost up. Really, to get it right, I'd need an EGT gauge and a wide-band O2 sensor... the O2 sensor is like $500, and the EGT for my Defi gauges is another $200. Ugh.

So I'll prolly run it at 1.1bar (16psi) and take it easy when I'm down at sea level, until I know for sure I can go more...

[sperry]

Originally Posted by AtomicLabMonkey

Well I'm not too hot on the idea of getting used gears, if they've got a lot of miles on them they can be noisy since they're set in a wear pattern from a different rear end. And changing the entire rear end, like the whole differential, means replacing the whole axle cause I don't think the axle tube/differential assembly comes apart. And that's a shite-load more labor cost

Good points... as they say, "you gotta pay to play". And all in all, you usually get what you pay for. Better to drop the $1000 on the right stuff for the rear-end than spend $500, and have to spend $1000 to do it over right the 2nd time.

[AtomicLabMonkey]

I just ordered the C&L 76mm MAF kit for the stang today... sweet.

[AtomicLabMonkey]

Originally Posted by AtomicLabMonkey

I just ordered the C&L 76mm MAF kit for the stang today... sweet.

This new MAF rules! I just installed it last night, it was fairly easy to swap out the old electronics into the new housing. It definitely picked up some throttle response and top end power, and didn't lose anything down low... Mo' Betta! Once I get the new intake manifold installed this summer, the car is really gonna fly. I talked to Ehren at MM a couple days ago and he's working on a new STB for 94-95 cars, so that should be out this summer and let me put the new manifold on. I offered to bring my car down to their shop for test-fit purposes on a 95, so I might even get one of the prototype braces before they go into production.

[sperry]

When you gonna get some higher compression heads? That's what's gonna really make mo' powa!!

[AtomicLabMonkey]

Originally Posted by sperry

When you gonna get some higher compression heads? That's what's gonna really make mo' powa!!

Actually aftermarket 5.0 heads usually don't change the compression ratio, they're just much less restrictive so more air/fuel mixture flows through into the cylinder. Plus aluminum ones weigh 40-50 lbs less than the stock iron heads, can't beat that.

[sperry]

Originally Posted by AtomicLabMonkey

Actually aftermarket 5.0 heads usually don't change the compression ratio, they're just much less restrictive so more air/fuel mixture flows through into the cylinder. Plus aluminum ones weigh 40-50 lbs less than the stock iron heads, can't beat that.

Hehe.... *iron*... that's like, so medival... Don't forget: we live in the future now! It's all about aluminum and carbon fiber and titanium and other stuff they make golf clubs outta.

[AtomicLabMonkey]

Maybe aluminum heads could come sometime next year... I have to get wider race tires/rims first though. Ugghhh... probably $1400 for new rims/tires, $1100 for new heads, then another $1000-1500 probably to have the heads installed. Why does car stuff have to be so damn expensive?

[AtomicLabMonkey]

Well now it turns out I am going to have the rear end worked on. It's gonna be $$, but it should be worth it after it's all done. The other thing that was wrong with my car besides the motor pinging at the auto-x was the rear differential.. I'm getting definite inside-rear wheelspin when I get back on the power out of a corner. Lots of understeer + spinning inside rear makes for a real strange feel exiting... so I'm gonna get the rear end fixed up first to isolate the handling problem, go to the next AAS event and use that as a handling baseline to figure out what I need to change in the chassis setup. The guy who's doing it for me is gonna completely strip out the rear end housing and clean it all out, put new seals, bearings, etc., rebuild the LSD real tight with extra clutches so it'll hold up for auto-x and put a FMS 3.55 ring & pinion in it. Should pick up the acceleration quite a bit.