The compressor polishing is a great price, here one of our big suppliers offers it at a converted to USD $108!
Is there a PrecTurbo rep on SupraMania?
- Thread starter Reign_Maker
- Start date
dbsupra90 said:
sounds good to me. looks like ill be posting this badboy for sale very soon. lol. ebay here i come. lol
Looking to do a gt40 of sorts when I get my tax return, not sure what I want really. I really wanted a gt35r but I dont think the funds will allow the extra $600. What I'm looking for is the gt40xx configuration that would yield me 500rwhp on pump gas (93oct- ~18psi) and spool ASAP. I'm not looking for some magically spooling turbo or anything but from what I've herd the gt4082's with a .81a/r exhaust was spooling BEFORE 4000.
So what would a gt4088 .68 a/r exhaust do relatively? The .81 does about 4300rpms full spool (according to jt2ma71's dyno graph on SF) would 4000-4100 be a good guess? And the same for the gt4082 .68 and .81? Approximate spool times: 3700 and maybe 3800? I would like a good balance of top end and spool. I'm not a spool nazi or anything
dbsupra PM sent about pricing- thanks
Chris
So what would a gt4088 .68 a/r exhaust do relatively? The .81 does about 4300rpms full spool (according to jt2ma71's dyno graph on SF) would 4000-4100 be a good guess? And the same for the gt4082 .68 and .81? Approximate spool times: 3700 and maybe 3800? I would like a good balance of top end and spool. I'm not a spool nazi or anything
dbsupra PM sent about pricing- thanks
Chris
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Opting for a .68 A/R turbine housing for a GT4088 or larger compressor wheel GT type turbo I consider a bad idea. Note, the GT4088 is 56 trim, which indicates the compressor wheel is 88mm (exducer) and 64.7mm (inducer). Also, the flow efficiency, volume (mass), and power delivery of this turbo is far superior when compared to other "T" type turbo's of relatively equivalent size. Therefore, there is a substantial risk of part throttle surging induced by the small A/R turbine housing. My previous SP63 was a surge monster when it was coupled with a .68 A/R.
The advantage of the "new" GT type turbo's, standard journal bearing or ball bearing, is its excellent flow pattern, so don't consider limiting and choking the turbo's flow pattern and performance by undersizing the housings.
HTH
The advantage of the "new" GT type turbo's, standard journal bearing or ball bearing, is its excellent flow pattern, so don't consider limiting and choking the turbo's flow pattern and performance by undersizing the housings.
HTH
williamb82 said:
hi howard-
i dont think there is a problem running the gt40 w/ a 68. it is bascially the same size as a sp67 and by no means does a 68 choke that down. sean dyno'd his car w/ the 68 then the 81 and saw very little difference. meaning the exh housing even at 30psi and 644rw it was not a restriction. granted he does have a 4" dp, but the housing was not a choke point.
as far as surging, he only runs idle and wot haha. but the gt40 does have an anti surge housing fwiw.
i dont think there is a problem running the gt40 w/ a 68. it is bascially the same size as a sp67 and by no means does a 68 choke that down. sean dyno'd his car w/ the 68 then the 81 and saw very little difference. meaning the exh housing even at 30psi and 644rw it was not a restriction. granted he does have a 4" dp, but the housing was not a choke point.
as far as surging, he only runs idle and wot haha. but the gt40 does have an anti surge housing fwiw.
BlackDevilSupra said:
well, i dont plan on using race gas so will never run the boost high enough imho to warrent a 0.81 turbine and would prefer the 0.68 for spool. i figure i should be able to get 550-600rwhp with this turbo and turbine combination on 93 octane pump gas and water injection and thats the goal, no juice or race gas.
dbsupra90 said:
nah, this car will be driven on the street, though no long trips do to the 1:1 final trans ratio of ha autoatic. also, i plan ona 3.5in dp if ossible. might be a tight fit welding a 3.5in vand to that turbo and then getting a 3.5in bend behind the turbo wit hthe ebay manifold. also, im using a 50mm wastegate to prevent boost creep. i figure with such a small a/r on the turbo the larger wastegate would help keep it regulated properly.
Your setup is identical to what mine will be william. I am leaning towards the .68 gt4088 as well, I want an easy 500+rwhp on pump as well. I want to try and get a 4" downpipe in there though, I will probably end up bashing the firewall in a bit to make it fit haha.
BlackDevilSupra said:
I never had any surge issues with the .68 housing on my SP67. I only lost about 150 rpm in spool up going to the .81 and it is still a blast to drive.
Sean
dave talked to precision this am about a/r sizing on the gt40. this is what they said-
I talked with PTE about this and here is the skinny. They do offer a .68 a/r T4 turbine on the GT4082 which has a smaller turbine wheel. They sometimes put the smaller turbine wheel on the GT4067 and have a .68a/r on that as well. But the GT4088 has the larger turbine wheel, and they do not have a .68a/r for that, only the .81a/r. He said they could make a custom GT4088 with the smaller turbine wheel and .68 housing, that will cost extra, he didn't tell me how much.
I talked with PTE about this and here is the skinny. They do offer a .68 a/r T4 turbine on the GT4082 which has a smaller turbine wheel. They sometimes put the smaller turbine wheel on the GT4067 and have a .68a/r on that as well. But the GT4088 has the larger turbine wheel, and they do not have a .68a/r for that, only the .81a/r. He said they could make a custom GT4088 with the smaller turbine wheel and .68 housing, that will cost extra, he didn't tell me how much.
hmm, the .81 gt4088 is a little more spool that I would like. Think the gt4082 with a .81 would get 500+rwhp on pump gas?
dbsupra90 said:
according to garretts stie they are both 77mm diameter turbine wheels. anyhow, id rather have the smaller wheel wit the 0.68 housing. lmk how much extra it would be. thnx.
williamb82 said:
ok so gt4088, gt cover. smaller turbine wheel w/ .68 housing. will do. cant imagine it would be much more since it is just some machine work involved. either way its still gonna be a lot cheaper than $850 + another housing
i'll let you know what i find out.thanks
dave
thnx. if all goes well ill have the cash for it maybe as early as next week.
edit: also dont forget the polished compressor housing.
edit: also dont forget the polished compressor housing.
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dbsupra90 said:
Mods = see sig. Sounds like about what I want though for a turbo, I'll be pm'ing you before the end of december with the money to pick up a gt4082 .81 a/r (assuming I dont change my mind again haha)
Thanks for the help-