building a SR20 stroker, need some turbo advice.

[zavala]

hey everyone,
just looking for some insight on to what turbo might be the better for what I’m looking for. going to be using a Brian crower stroke kit with 86mm(bore)x91mm(stroke), now the whole point of me doing a stroker is to get rid of as much lag as I possibly can but still be able to run a decently big turbo. I’m been looking hard at the GT2871R and the GT3076R, wanting somewhere in the 400-450whp range with a really sickening spool. also should I go for internal or external waste gate for that much power? below is a list of what I’m working with so far so let me know what you think

list:
SR20det S13 red-top
BC 91mm stroker crank
BC econo rods
CP piston
BC 272/272 cam
BC stainless valves (stock size valves, anyone have any links to info about bigger valves?)
BC valve train kit
Greddy oil pan
"Jun style" intake manifold
850cc inject
ect.

the list goes on longer than that of course but that's pretty much the main things I’ve got going now. I know that it seems a bit extreme and expensive and that no normal car owner would take it upon himself to do this himself, but I’m a seasoned mechanic and own my own shop so feel free to let the technical jargon start flowing. thanks, Justin

[mjjstang]

no lag on a 450 hp 2.2 liter motor? I have a gt2871r and 400 let alone 450 hp has never entered my mind, albeit I have the measly .64. the GT3076R will be your friend, being that it is a BB, it will have as little lag as possible. Should get you into at least 400 to 450 range. External gate for you most likely.

[street240]

I would also go with the gt30

[turtl631]

If you hate lag that much, build a KA instead. Stock stroker! You could also look into running a full-race twin scroll manifold with a twin scroll gt3076, perhaps the .82 A/R housing? Or do that setup, on a built KA with some Crower cams. It's going to require an external WG for sure, the FR mani uses a 44mm Tial vband WG.

[zavala]

well i've got a friend with a used GT3076R and a tial 38mm gate for dirt dirt dirt cheap, so i'll deff look into that. also, and know what boost responce is on a GT30? full boost by what rpm?

[Jesses240]

know what boost responce is on a GT30? full boost by what rpm?


A friend of mine made lil over 360 awhp with cams/exhaust/tune and a gt30r on his evo... yes i know its not a sr or nissan for that matter but i figured i'd share anyway

I believe he was hitting full boost (around 24psi if i remember right) on pump gas before 4000 rpm... i think it was more like 3600rpm but its been 1.5 years since he dyno'd so i can't remember exactly

[sonnysmr2]

my buddy also has a 3076 on his evo, 3076 all the way........i wanna see one on the sr!! i know it will match up well. dont worry about lag issues either shit spools no prob.

[Sileighty_85]

My buddy had a Plusar GTi-R with the SR20DET and was rollin with a T-67 sh!t was sick good spool up pushin around 400Hp runnin a fully built head, stock Pulsar Interals (except for bearings) with a Wolf 3D EMS. I've watched him burry the needle past 2.0KpA on his defi

[GSXRJJordan]

The GT3076R is the most common GT30 turbo, so when most people say "I've got a GT30R", they probably have the GT3076R with the .82 hot side. Anyway, as far as power gains, I've personally driven/seen dyno'd an RB25 with a GT3076/HKS ext WG, and with a conservative (drift, not drag) tune with stock internals/head/valves/cams, we hit 404whp, with INSTANT spool. Your stroker SR should spool around 3500 with your mods, and you'll have a little headroom @ 400whp with the GT3076. I recommend a stand alone, but you probably already know that.

About valve size - everyone I know that builds SRs sticks with stock valve size, because they're already fairly large for a 2.0L. If you go to oversized valves, you gain flow POTENTIAL at high RPM, but you sacrifice flow velocity at the lower RPMs, shifting your powerband even further into the revs... point is, with this motor, there's no need for oversized valves. The same goes for porting, but to a lesser extent; I've seen large flow gains from porting and extrude honing, but these usually don't result in large hp gains (the extrude hone doesn't have any large downsides though, except time and money).

[zavala]

yeah so it turns out my buddies GT3076R has the "twinscroll" split housing, so i'm wondering if i had a custom pulse tuned manifold built to join the 1&4 and 2&3 banks at the collector with a split in it to match the two slotted housing for quicker spool. am i right on this? it seems to make perfect sense on paper

[GSXRJJordan]

The problem with "pulse tuned" anything is that they're tuned for a certain RPM/flow range, and it takes compromise to make anything streetable (especially if you're concerned about spooling early). An short length, equal runner manifold is considered a good trade off between top end flow and spool, but yet some of the highest HP supras run 'log' style manifolds... doesn't make any sense on paper, but they swear it spools the big turbos faster. I guess my point is that I follow those who've been successful in building cars crazier than mine, and I don't know of anyone that has gotten the fantastic results you'd expect from a twin scroll turbo/tuned manifold setup. I know Bill @ Dent Sport Garage has a special manifold for his SR, so I'd email him and Full Race and see what they think. Just know that any product coming from either of them is going to cost a kidney or two.

[zavala]

yeah I found the exact manifold I was talking about last night, about a hour after my post. full-race makes it for about $1500, http://www.full-race.com/catalog/product_info.php?products_id=1065
we'll see about it, we are busy as sh*t at my shop turning out cars so money really isn't going to be a problem. I just what to make sure I’m making the power though over all. now if I can remember back to my diesel mechanic schooling, "diesel engine exhaust manifolds are "tuned" to deliver to the turbocharger exhaust gas with minimal and balanced flow resistance from each cylinder." "if the exhaust manifold and piping is properly designed as each slug of cylinder exhaust is discharged, it will not "collide" with that from another cylinder but instead will be timed to follow into it's tail stream." now I know we don't have diesel engines in our car, but in terms of spool and tongue we can take a big lesson from our big diesel brothers. after all they've been in the turbo game wayyy longer than we have.

[zavala]

well i accually got the turbo in my hands tonight with the waste gate and it turns out he (my rich but dumb friend selling me this stuff)was a little off:wtf: . turns out its a GT3071R 4-inch inlet, V-band exhaust outlet straight outlet not split like i thought T3 style. and the tial waste gate is a 38mm with a 44mm vent side. the whole combo has 2000-2500 miles on them from a failed project by him (yes, i saw the car it was on and no it was not run hard.). bought it for $750 cash, figured it was a good deal. will this get my 2.2 272 camed SR20 into the 400-450hp range? will the torque be in the 400's?