250 HP 0-60 times ?

[statager]

Hello fellow alfisti !

Im in the progress of renovate my old 1986 2.5 V6. After the engine rebuild im planning to buy Greg´s SC kit + liquid to air IC, S cams and some performance headers to hopefully bump the power to around 240-250 cranck HP @9 PSI

My question is, what kinda performace can i expect with the 4.11 diff+Lsd in terms of 0-60 mp/h times ?
How much torque can i expect the little 2.5 12 valver to chunk out @ 9 psi ? Im hoping around 300 NM.

Im shooting for 5.8-5.9 sec times, and in terms of power/weight ratio it should be able to get there. Im just curious if its realistic.
1160 kg / 250 HP = 4.64 kg/HP , thats alomost as good a ratio as a Euro BMW E46 M3 (4.55)

Regards
Jesper Statager

[jontg428]

Hope the driveline can handle the hard launches, the transaxle cars are not really meant for drag racing, but I am sure your car should be pretty fast!

[Rookie ROX]

You'll find that those with the power tend not to do much from a standstill, simply because the transaxle doesn't like it.

I'll let you know how it goes soon though

ROCK ON
R~R

[slyalfa]

even stock the wheel hop from a sand still is very bad if you add a littel to much power.
but after you get going it should be a blast.

[Greg Gordon]

I generally try to stay out of these posts to avoid a commercial self interest issue. However it seems there are some out who haven't seen the drag race video I made. I think this shows how a supercharged Alfa 2.5 holds up against the current crop of fast sport compacts.

The drag race is between a 2006 Chevy Cobalt SS supercharged and my old supercharged GTV6. At the time this version of the Cobalt was the fastest sub 30K car you could buy. It was quicker than the WRX, Civic SI, etc. The Chevy's 0-60 times have been published over and over so they give a pretty good comparison. The GTV6 is a non intercooled, L-Jet car with water injection on an otherwise dead stock engine. The GTV6 does have an intact converter and stock manifolds.

YouTube - Supercharged Alfa Romeo vs Cobalt SS supercharged

[jkramer9]

i just watched that video, and that was insane, i didn't think the Alfa was going to win by that much and in my eyes the Cobalt is over-rated, sweet vid though

[BigSwede]

I like the way you see the camera-guy in the side mirror grinning like crazy.

[Greg Gordon]

That camera guy is my son (yes, I am a bad influence). The owner of the Cobalt is our friend.

[ToonRboy]

Hi statager,

As long as you're rebuilding that motor, I would say drop the compression a point. Will cost you more in machining, but will enable more boost (and power) and at lower boost, you might even get away with turning off the water injection. The other thing, I would get Verde cams instead of the "S" cams for this application. You can get e'm for virtually free and I think you'll like the torque. Remember, you don't want (or need) all that overlap with blown engines. Take the money you save there and replace your giubos, and re-bush your tranny mounts...

I think 250 is a little optimistic for the 2.5, but with Greg's kit, I think you can get close to the performance 0-60 you were talking about (Milano a couple hundred pounds heavier than GTV6). Take a look here (closest official performance numbers from similar power) Callaway Twin Turbo GTV6

Good luck,

[Bill-Sims]

Go for it! But be sure to include the PWR water-to-air intercooler, even if you reduce the compression.

I relied on water injection after installing the supercharger, and it cost me an almost brand-new engine when high speed detonation occurred and destroyed a piston, which at 7000 rpm destroyed everything else. The intercooler will not fail, at least as dramatically.

As for the driveline, you simply cannot do any hard launches. You'll break the ring gear (I did this on previous Alfetta race car). Besides, the tire spin is not necessary. Launch easy, then feed gas so the tires are barely spinning.

I've been surprised that my doughnuts have held up just fine. Then again, the car is only used for autocross.

Not many miles being put on!

[BigSwede]

I'd say the ring gear problem is due to the slicks. I have never heard of any failures here and we do plenty of hard launches in our racing series. We use "Semi-slicks" over here.

[statager]

Thanx for the input guys.
This car will prolly never see a track, so no slicks here

I will be running Dunlop SP street tires 215/35x17 front, 225/35x17 rear on Rial Como rims

[Bill-Sims]

The broken ring gear was in an Alfetta with only 170 hp and street tires.

Richard Jemison built my transaxle. After a year of autocross he checked it and found my magnesium case was expanding. He reshimmed the ring and pinion and warned me that I'd better take off easy from now on or I'd break the rear-end. I can't afford to be buying new transaxles, so I heeded his word. Like you said, those big R compounds can put a real stress on the driveline if the car is launched.

[Bill-Sims]

Transaxle that Richard built is in my Milano autocrosser--sorry, I realized the previous post was confusing to read...the broken ring gear was factory original in an Alfetta and had never been worked on.