Ebay Turbo?

[IsaacHayes]

Robert was OBD"1.5" the gray-area cross over years (94-95) were still speed density, technically still OBD1, but a bit more advanced PCM that was flash EEPROM based which no body has anything to tune.... Most go OBDII to tune that have that year but Robert was the first successful to go to OBD1. He didn't go to the A-body weird MAF setup, but with 91-93 DOHC PCM since it can do the electronic auto.

[ghrarhg]

What motor do you have? if your going from a T25 then i would stick with a T3/T4 or you will have allot of lag. Don't do the ebay turbos..... Chineese ones i have seen are fricking glued together and over 5psi fall apart lmao! stick with a reputable company or someone with alot of feed back.. you don't need a ball bearing turbo for it to spool fast.. if you have the right turbo for your car a jearnal bearing turbo is fine, make sure it has a 360* thrust bearing at minimum...

http://cheapturbo.com/

I have a cammed 2.8 with a 3400 top end on it. I'd like to keep the T25 flanges though for now. If I was willing to redo everything again, I'd probably go Holset all the way. I realize that I don't need ball bearing to have it spool quickly, but I'd like to keep the spool similar to what I have now with a little more up top, which is why i was thinking disco potato or maybe gt2871r. There isn't a whole lot of bottom end with small bore short stroke combo. To make things worse, I lost a few tenths in compression by switching to the gen 3 top end, so overall, the sooner the boost the better.

[pocket-rocket]

MAF, what MAF? only the a-bodies got them...

the turbo has yet to be installed, but i have taken it apart MANY times....

once too many actually...... bad story there.

I was under the impression some others in that gray area besides A bodies were MAF. Then again, I don't care for MAF so I don't keep up on what has it and what doesn't, lol.

[SofaKingWeToddDid]

yeah i know nothing about it and would probably look for a good one off of a write off car or something... lol maybe a t bone or rear end (those sound really sexual) so the engine is still good.

[IsaacHayes]

A-body had removeable PROM and tunercats has a def for it. So that is actually tuneable. 3400-modified tried to swap to that on his Beretta but some grounds and stuff weren't right and he gave up. The A-body setup is probably closer to a 3800 setup or something. It is really weird in that it doesn't even have a MAP. It's all MAF which is built into the throttle body (on a 3100!) and the UIM and TB bolt up differently to each other than normal 3100s. /offtopic.

[robertisaar]

A-body had removeable PROM and tunercats has a def for it. So that is actually tuneable.

there is also a XDF for TP...

and yes, the a-body stuff and the 94-95 LQ1 setups are actually very similar to the 3800 setups.

/3800 references

[RedZMonte]

I have a cammed 2.8 with a 3400 top end on it. I'd like to keep the T25 flanges though for now. If I was willing to redo everything again, I'd probably go Holset all the way. I realize that I don't need ball bearing to have it spool quickly, but I'd like to keep the spool similar to what I have now with a little more up top, which is why i was thinking disco potato or maybe gt2871r. There isn't a whole lot of bottom end with small bore short stroke combo. To make things worse, I lost a few tenths in compression by switching to the gen 3 top end, so overall, the sooner the boost the better.

I would honestly rock a Good old Standard T3 turbo, its going to spool fast, be more effiecent then your T25. they are dime a dozen so they are dirt cheap but you would have to change your flanges or build adaptors... you can't go anything bigger w/o changing flanges from the T2 flange you have now. on your motor setup you would be hating life if you went to anything larger, you can get a more efficent smaller turbo if you want to spend a GRIP of $$.. a T3 is a nice cost to performance bang for the buck. ive seen new T3's for like $300-400 new name brand turbos. there was a local turbo specific shop to me that is no longer in business (owner died) that would build me a new T3 w/ all garrett parts for $350 in any configuration i wanted..

S

[Joseph Upson]

Definately a T3 .60 compressor and .63 turbine to .82 if you're gonna run it on the high end. As already stated stay away from the ebay ball bearing turbos, I just read a negative to one of the sellers of a GT35 BB turbo that worked for about a week according to the purchaser. Since I'm going to single turbo setup I'll be selling off my twin T3 .60/.63 turbos at some point, one is a genuine Garrett T3 the other is a rebuilt Garrett with aftermarket compressor wheel and center section.

I'm gonna break down and go name brand until I can get some more input on the dependability of the larger aftermarket turbos because I'd hate to spend $500 on a turbo or any amount for that matter and it fail in short time with no warranty.

Their warranties are kind of shady anyway; must be installed by certified technician... obviously the durability tests are performed by the buyer bc the sellers and the manufacturers apparently don't go any further than trying to match size and dimensions.

[ghrarhg]

I'm bringing this post back from the dead rather than starting a new one because the issue still holds.

I ran my blown seal t25 for the rest of the year. It probably could have passed for a mosquito fogger, but that's over with. It's now winter in Northeast Ohio, and I have a solid 4 months before this car is back on the road.

I've decided that I'm willing to spend some money and do it right. I'd like to keep the total under $800 or I'll have to deal with the wife. I can do the fab work so that's not an issue with switching from the T2 flange. It sounds like I'm looking at a T3 super 60 or T04e-50trim. Looking at maps, it seems like I'll be in a better efficiency range with the T04e.

Any suggestions?

Also, if I do end up going with anything not T2 flanged, I'll have a rebuilt TGP crossover for sale if anyone's interested.

[Joseph Upson]

For best performance choose the turbo with the MAP that just does cover your expected power range. Too much turbo means lag so your plots should run up the center of the MAP before peaking out to the right. Whenever your plot points run up near the left surge line and then peak in the center island you will have noticeable lag as the larger the turbo is relative to the required flow, the further your plot points move toward the left indicating an oversized turbo for the job. The center island would be great for turbo efficiency but may not offer the overall greatest performance.

[ghrarhg]

Looking at the T3 Super 60, it looks like it runs out of air on the upper end, while the T04e 50 trim will definitely flow way more than I need it to. I know I have a weird combination of 2.8 w/3400 top, but what sort of VE am I looking at (ballpark)?

Here's my first cut at it with the 04e. Left side starts at 3000 rpm, right is 6200.



Here's the T3 Super 60



Edit: Here's a T04e-46 Trim too.

[robertisaar]

none of those maps look too good... what is your compression, TB size, downpipe info, the rest of your exhaust info and cam specs? i'll see what desktop dyno is saying if you can get me that info.

[ghrarhg]

Compression is 8.5:1 using the CR calculator. TB size is the 3400's 56mm. Downpipe and exhaust is 3" mandrel bent and splits to 2.5 behind the rear wheels, no mufflers at preset.

Cam Specs:
(to lazy to type)


Thanks

[robertisaar]

i came up with this:

included a stock 2.8 and 3400 for reference.

[TiredGXP]

How odd, I came up with nearly the same VE numbers, but considerably lower power and torque.