hpfiend Posted September 3, 2012 Report Share Posted September 3, 2012 Hey all- 2700 lb gremlin 355 sbc, 3.73 gears soon , th350 with 3000 rpm stall, shooting for low 10s in quarter from a blow through single turbo carb setup- from my limited experience both the bullseye s475 and master power t76 look pretty good, which would you go with and why?- are there any on3 maps available anywhere for the 76mm? Thinking 15 psi should be enough.. Need about 650 rwhp I believe... As the car currently runs low 13s at 95 mph that puts it what 250 rwhp? Going to put a cam and the new rear in soon as it has one too large and only 2.56 rear gears now.... Quote Link to comment Share on other sites More sharing options...
Ackbar00 Posted September 3, 2012 Report Share Posted September 3, 2012 MP T 76 will do that easily and for the lest amount of money. S 475 will have a bit more room to grow, but it is a T6 flange. Might be a tick laggy, but will make a lot of power. Quote Link to comment Share on other sites More sharing options...
AJ Posted September 3, 2012 Report Share Posted September 3, 2012 I have a pair of turbo's and waste gates I'll sell you that will work good on that engine. Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 3, 2012 Author Report Share Posted September 3, 2012 Thanks guys! AJ are they big enough just to use one?? I really only have enough room on the drivers side for the one turbo and the other side I need room for the air to water intercooler... There isnt really enough room in the front for an air to air and the associated plumbing Quote Link to comment Share on other sites More sharing options...
TurboNova Posted September 3, 2012 Report Share Posted September 3, 2012 S475 hands down, like stated lag might be minor but your engine is the limit with that turbo, just get a good gate! Quote Link to comment Share on other sites More sharing options...
AJ Posted September 3, 2012 Report Share Posted September 3, 2012 No. I spent a great deal of time talking to a lot of turbo company's to size twins for no lag and 1000 hp on a 355sbc. So one would only do about 500hp. Quote Link to comment Share on other sites More sharing options...
Mattsv8 Posted September 3, 2012 Report Share Posted September 3, 2012 Someone on ls1 tech just made 647 I think with chads bb 76. Master power is no longer selling to general population. I think there modular turbo or something like that. Keep your exhaust housing large. Wich will keep the backpressure in check. If u could get a s480 or s488. 80mm or 88 mm 1.32 exhaust housing. Also your 3.73s will be way too much gear for a ca4 that light. Id start with 3.23 Quote Link to comment Share on other sites More sharing options...
hpfiend Posted September 4, 2012 Author Report Share Posted September 4, 2012 Thanks! It looks like the s475 is the cr favored option to get and play with the housings to minimize lag... I am building the headers so a t6 flange shouldn't be an issue. I am trying to learn as quickly as I can but isn't a s475 a 75mm turbine? With the right A/R housing wouldn't the 76mm make more power? Or are those housings just not available? What makes a good versus a bad wastegate? Aren't they a pretty simple design? Does anyone know of a website or shareware that will plot various boost levels and rpms, CID on a compressor map to test for a match or should I see if I can make something up myself- kind of tedious to do it manually? How do tell spool or lag-factor from those efficiency maps? Is it the cutoff at the bottom? The reason I ask- and I will have to double check but the T76 map I saw was very similar to the S475 as far as the flat level rpm at the bottom... Quote Link to comment Share on other sites More sharing options...
Ackbar00 Posted September 4, 2012 Report Share Posted September 4, 2012 I cant get it to post. Open google and put in s475 vs t76 look at the images. S475 is massive compared to the MPT76. Support bracket will be manditory for it. For wastegates, its mainly down to build quality. Heard of a lot of people using cheap 60mm Ebay gates and working. But have heard of my share of failures as well. Dont tend to hear about failures on quality gates. Good gates would be, Tial, Turbonetics, JGS, turbosmart, HKS. I still just run a Tial 38mm on my 410cu inch with a GT4202 T4 flange. I can run 8 psi no issues. I would think a 44-50mm would be just fine. Quote Link to comment Share on other sites More sharing options...
TurboNova Posted September 4, 2012 Report Share Posted September 4, 2012 ^ this is true, make sure you have ample space and enough to make the serious downpipe it needs, they have adapters to neck it down after the exit but if memory serves me right the size out of the exhaust turbine is fairly large Quote Link to comment Share on other sites More sharing options...
Ackbar00 Posted September 4, 2012 Report Share Posted September 4, 2012 S475 is 5 inch. MPT76 is 3 inch. Both are v-Band This is most cases. Quote Link to comment Share on other sites More sharing options...
TurboNova Posted September 4, 2012 Report Share Posted September 4, 2012 unless you get the q trim and it is 3.5" vband outlet Quote Link to comment Share on other sites More sharing options...
Mattsv8 Posted September 4, 2012 Report Share Posted September 4, 2012 I beilieve there's been a few at 1000hp with either. The s475 1.32 housing is great for a v8 at 15 psi your back pressure will be low like 1.1 id recomend a s480 if the price is good. Quote Link to comment Share on other sites More sharing options...
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