what outcome should i expect from either? i want quick accel but nothing thats gonna spin tires thru the whole run. a local ex-TD street racer (in the 80s) is telling me to use the .48 and get rid of the .63 if i want the best overall power and accel. i have a 2.5 CB bottom and a t2 top end and putting on a 50 trim hybrid turbonetics. thanks
travis
What car?
Do you even leave 2nd gear?
auto/manual??
gear ratio??
tire size??
I think a 50trim .63 stg II is good for a 2.5 but may have a little lag for autocross, a 46 trim stgII .63 may be the best for you
read this thread it may help
http://www.turbo-mopar.com/forums/sh...ght=.48+hybrid
He says here some things here
http://www.turbo-mopar.com/forums/sh...7&postcount=56
love my true S60 turbo on my 2.5. I don't AutoX on it but love the tight twisty 15-35MPH corner stuff with some straights. Don't have any problem with lag. Besides like Carroll said, if you have lag you aint driving it right. The fuel curve has more to do with power delivery than when boost hits or doesn't hit.
And what other mods? Which AutoX class?Originally Posted by Speedeuphoria
My bone stock '87 CSX #252 used to burn one tire or the other all the way around the cones running street tires...
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Why do you think there would really be any autocross difference between two turbos with the exact same turbine, exhaust wheel, and almost the exact same compressor wheel.....? Since traction wont allow him to use all the power those turbos could make its really not an issue of where one compressor wheel maxes out and the other can keep going.
Biggest deal for him would be picking the right turbine and exhaust wheel.
Thanks for picking my answer apart w/o giving suggestions to the original poster's question. Thats very constructive. Since you make assumptions about his lack of traction, you must give your insight as you have the most knowledge about his car, please advise.
Anyway Part of the reasoning why I asked what size tire/trans ect..
sorry, its an 89 daytona shelby (hopefully i can get it down to 2500 lbs), manual a520 (will try a a555 later). and no, i dont leave 2nd gear. thanks guys for the suggestions keepem coming
I'd port the exhaust manny, get an S60 turbo, put 3" Mandrel bent exhaust on it and a good intercooler. But it all depends on what class you are running in. You mod it too much and you're in a class with corvettes and porsche's and you're not going to be competetive.
If his plan is to drop a daytona's weight down to 2500lbs, I'd say he plans to run in a Prepared/Modified class. I'd suggest SM, but I don't think you will find 400lbs to remove to run that class.
I autocrossed my shadow every weekend for a couple of years. I made due just fine with TII turbo and Gbody Intercooler. You don't need a big turbo for autocross. Unless you have AWD, you won't be able to put the power down in turns. Best bet would be the larger housing. The lag at least will help with coming out of turns under power.
Focus should be spent on suspension. Make sure you have the rearend aligned. Get a 3.77 or 3.85 gear ratio tranny with LSD. The 3.50 gear ratio trannies wouldn't work good. I switched to an 568 because of gearing and LSD offerings 6yrs ago. If I was still running a shadow, an A523 3.77 transmission with Neon LSD would be my setup.
Turbododges other then Lbodies handle like crap in autocross. After 6 yrs, I learned my lesson by buying a neon for autocross.
James Dempsey Jr 91 Dodge Shadow ES convertible 95 Dodge Neon Sport sedan 2.4 5spd
id barely turn the boost up at all. Like 5-7psi. you dont really need a ton of power, you need lots of traction (LSD) and suspension mods.
Franks old V6 shadow didnt do too bad at autox. a few 10ths off of the class leading neon.
Brian
I'll admit to just skimming through the posts, but I didn't see anybody mention running a .48 turbine housing with a clipped stock wheel.
If traction is a problem from abrupt boost onset, I'd think clipping would be the most cost effective way to make the power more managable. Definately not a good solution for a drag car, but might work great in this application.
yeah but then when you are on the street and want power, clipping makes it suck.
Brian
Agreed, especially when you take into account how fast the .48 housing becomes a cork. The clipped wheel would make it spool a little slower, but the .48 housing would still have it running out of steam on top. This would result in a bit narrower powerband (in theory). On the other hand, the later, less violent spoolup might be just the thing for traction in an autox car, and would be less expensive than than playing with housing/wheel combos until he found something that worked.
here is a good idea as well. make a custom header over the trans and make the turbo attach to it with 2 v-bands (inlet and exhaust) for the exhaust side and make adapters so you can slap a mitsu in there for autox and the 50 trim for the street.
keep the boost low with the mitsu though so it doesnt boil the tires with the quick spool.
Brian
My best runs with autoX was with a mitsu! But I had a 2.2, so a T2 garrett would probably be OK with a 2.5L. Although on a modded engine the S60 spools just as fast as a stock T2 turbo, the boost hits harder and will make you spin your tires. Stock T2 turbo, or S60 with the .48 would be OK too.
Daytona Shelby is not make for autocross. I know, I have one.
This is an autocross car..and people boil the tires with stock setups....no matter how good the tires get traction will be an issue.
You suggested a whole new turbo.
He just needs to pick the right exhaust turbine/wheel setup to find the spooling characteristics that he needs.
I cant give personal experience autocrossing between .63 and .48 turbine housings but I know that the other suggestions you made wont help him improve. Im sure someone here has real life experience with the turbine differences. I would prefer something that spooled slower.. but i always cringe when it comes to wheel clipping. .....it may be the answer though.
if the .63 turbine still hits max boost almost instantly (at a higher rpm) then it isnt going to help much. If that doesnt happen then great!
My daytona handled 4 times better than my shadow ES from the factory, and the shadow has lower profile tires
An LSD is almost mandatory equipment for autoX, I didn't have one which is why I only spent quite a short time autocrossing and more time drag racing.
BTW, wheel clipping is never the answer to anything....you clip the wheel, you've ruined that turbo. You want more lag, run a larger turbine.
I ran an S70 with the .48 housing before (stock turbine wheel), doesn't hit as hard as with the .63 housing. I didn't like that setup but thats because I like hard hitting boost. Probably would have been a decent setup for autoX.
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