fl327 Posted December 28, 2002 Share Posted December 28, 2002 man decisions decisions. decided to off my lsd unit, gears too steep for my commuting butt, took the 3.90s out yesterday, and man do i hate working back there. took the torch to the mustache bar, dropped in the poly, and replaced the front mount, lubed the sucker and plopped the 3.54s back in, five hours of screaming, grease, dirt in my face, and more screaming. my rear suspension is clean, i thought, i got out from under there looking real ashy and every muscle from my neck to my knees is sore today, and i was taking a fifteen minute brake every hour on the hour. oh well, i did the work clean and put loctite on everything that matters, and a real nice freeway rpm now, but maaaaaaaaaaaaan, if i had money, i might pay somebody to do this stuff. Quote Link to comment Share on other sites More sharing options...
blueovalz Posted December 28, 2002 Share Posted December 28, 2002 Just out of curiousity, what kind of tranny did you have and the tire size on the rear. I'm considering 4:11 gears with my T-5 5th gear and am concerned about the highway travel. Quote Link to comment Share on other sites More sharing options...
fl327 Posted December 29, 2002 Author Share Posted December 29, 2002 i run 225-60-15 and have 81-83 na trans with deepest od, and fifth gear still felt like i shifted into fourth twice, my street gearing went by too fast to even spool 10 psi, i would hit redline not even hitting my max boost. i think for an na application with a high lift cam of a short duration, like your car probably is, 4.11 would rock. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted January 1, 2003 Share Posted January 1, 2003 I know what you saying. I got a early z trans with 11lb flywheel and 3.90 gear. I can't really get the boost up to 10's until end of second and thrid gear. Well, may be I've not tried hard enough I need more fuel. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted January 1, 2003 Share Posted January 1, 2003 Thanks for verifying what I have been preaching about gearing for turbo cars. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted January 1, 2003 Share Posted January 1, 2003 Scottie, I think that holds true for ANY high HP car. You'll notice that the very high hp cars don't run the 4 series gears that they used to. I know my supercharged mustang was faster and more fun to drive with 3.27 gears instead of the 3.73's I started out with. I was making right a 500rwhp, Vortech YS trim . Shifting a Tremec 3550 Quote Link to comment Share on other sites More sharing options...
rags Posted January 1, 2003 Share Posted January 1, 2003 Scottie, seems like all those running turbo's have to find out for themselves Joe Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted January 8, 2003 Share Posted January 8, 2003 After my turbo engine swap, I test drove the car with my old R200 4.11 that I used very successfully with my high reving N/A L28. Funny as heck.. with almost 1500rpm less to play with, I was shifting like a madman. I raced a newer DSM, and I was winding 3rd gear as the DSM was just still in 2nd. hehehe Anyways back to the reason for this post. I could not build full boost in any gear.. 5-7 psi that was it...Well all in the same day, I brought the car back to the shop and we swapped in a 3.9 that I had laying around at the shop.. The boost came up a pound or two.. (no mods..just the diff)I blasted up the street a couple of times then brought it back. Right there and then we swapped it out again, and dropped in a 3.54 that a friend had left in storage at the shop..Now I had boost! Now I could hit max boost in all gears! (12psi) Unfortunately I had to return the 3.54 diff, as I purchased a lsd unit that had 3.7 gears in it..I'm not entirely happy with the 3.7's..I'd like to swap out the crown gear and make it a 3.54. I'll get around to it... (my boost is now uneven in each gear.. boost a lb or two low in 1st. perfect in 2nd and 3rd, and too high in 4th and 5th.. 3 diffs within 3 hrs.. Quote Link to comment Share on other sites More sharing options...
speeder Posted January 9, 2003 Share Posted January 9, 2003 Been there. I first operated my '77XT with a T3/T4b (.63 SII turbine, 50 trim comp, internal wastegate) with a 3:90 rear. The car had a good feel to it, spoolup was super fast, but it didn't have the power I expected or achieve what I thought was enough boost for that setup.Boost control with my HKS EVC was effective and crisp. I then switched to a 3:36 I had laying around the shop and the car was transformed - boost in abundance! Problem was, now I had too much, and my smallish internal wastegate wouldn't keep boost from spiking. Spiking isn't the correct term, because boost would go to the desired setting,linger for a brief time, then climb right up uncontrolled. I had decided to go to a big external wastegate but before that happened stupidly kept tinkering with the car. One day while trying some hairbrained scheme (that I won't elaborate on because it's embarrassing to talk about)I spiked the boost in major fashion and after that the turbo was noisy and broke - (compressor surge?) I would have liked to see how the original turbo worked with the 3:36s and big Turbonetics Racegate that I installed next, but at this time I had Reed at Turbo Specialties build me what he calls a T61 - Essentially a T4 in a T3's body. After some (lengthy and tardy) warranty fixes to the turbo, this new setup is a monster. The big turbo has 12 psi by 3200 rpm in any gear,and boost control is rock steady, absolutely straight line at any boost level from 7 psi on up to about 18 psi. And there's lots more there when tuning and race gas permit. This has gotten a bit long -winded, but the point is, Turbo cars like the load characteristics provided by long gears. ( Can I have an Amen Scottie ) The bigger the turbo the longer the gear you need. I think I'm going to try to talk Ross C. out of those 3:15s he said he has. Also, I feel your pain, brother. Throughout this deal I've become a diff-swapping expert.And I've just pulled the diff again to have some LSD problems worked. Isn't wrenching fun? Quote Link to comment Share on other sites More sharing options...
fl327 Posted January 10, 2003 Author Share Posted January 10, 2003 i dont like working back there at all, hey at least im getting my full boost in every gear, cant wait till this clutch starts giving out from all the boost load! Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted January 11, 2003 Share Posted January 11, 2003 len -the night before motorsprt show 3 years ago i tore out the lsd rear in my car because i over tightened the pinion nut swapping pinion flanges.removed it ,replaced pinion brgs & seals and installed it in 3 hours.but thats what you can do when you work at a dealership with your own rack and tools,and air.i build diffs at work -i get lots of practice. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted January 12, 2003 Share Posted January 12, 2003 Okay, update. I can get full boost with my set up as long as I can hook. I can't hooked the 1st gear but as soon as I get 2nd and hook, I get full boost. Quote Link to comment Share on other sites More sharing options...
fl327 Posted January 17, 2003 Author Share Posted January 17, 2003 with the 3.54 and my rotten 215/60s, i cant hook for nothing in first, even from a roll, god i love it. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted January 17, 2003 Share Posted January 17, 2003 Well, with 3.90, I can loose traction in 2nd from a roll. I think I need to loosen my rear suspension. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.