rb 20det with a hks 3037 and need help

[beario]

hi all pretty new here,just want some advice i ahve recently purchased a hks 3037 gt turbo on a hks high top manifold, external wastegate etc etc...question is will this be ok to run on my standard internal rb20det 125,000klm engine...i have a hks hyper cat back exhaust,de cat,front pipe,hks bov and filter,gtr front mount intercooler,trial ecu with 1 bar upgrade,apexi s-afr,(i plan on fitting some tomei 256 inlet and exhaust cams at some stage also)the injectors are stock but has a gtr fuel pump....what sort of charecter ristics would the turbo have on this engine i.e when would the boost come in early or late,what rpms,would i get much of a gain from this..estimated bhp figures.....or what does anyone else suggest..thanks for any help...

[Steve]

you will need to upgrade your injectors, the stock ones dont go past around 230rwkw.

I made around 256rwkw(430bhp approx) at 1 bar, and 285rwkw (470bhp approx) at 1.2bar with the 3037S 56T (on RB25 @ 7000rpm).

where it makes boost will be dependant on your exhaust housing and how well the exhaust side flows, also the rest of your setup.

to give you an idea, on RB25 I had around 1 bar at 3000rpm with 0.61 A/R ratio turbine - it was very switch like, ie boost was on or off, and at 1.2bar it was unstreetable, even in 4th gear with light throttle the back end would swing across lanes:(

I went to 0.87 turbine housing, it became very laggy, until I upgrade to a 90mm exhaust (had a restrictive, ie quietish, 80mm exhaust) - and now it is alot better to control with throttle, rather than being on/off - now I am making 1.2bar at just under 4000rpm.

I dont know what size housing you have, but would think a smaller one would be the go, perhaps a 0.73 - wind the rev limit to 8000rpm and enjoy. If you already have the turbo, I would suggest you fit it, then if things arent quite right, go from there, ie different turbine housings/exhaust system etc. Just make sure you sort those injectors out ASAP.

Stock RB bottom ends are quite strong, as long as you have the right support systems (fuel) and make sure your car is tuned well. I just spoke to a Japanese mechanic (works for Signal) - he seems to think the best way to tune is with 11:1 AF ratios max, and wind in timing to get good power and responsiveness. I told him I was making 285rwkw at 1.2bar, he seemed to think this was a bit low, that my car would be much quicker if I tuned it with 11:1. He thought my timing was a bit conservative but the fuel was too lean (currently it uses 11.6:1 at peak torque and 12:1 thereafter) - he was concerned enough to ring japan and get a mate of his to check some maps they had, so he could make some rough adjustments to keep it safe until I got it on a dyno!

sorry, starting to waffle on a bit.

the guts of the matter is, as recomended to me by a mechanic that works for a japanese performance shop, tune AF ratios no more than 11:1, use the timing to bring up repsonsiveness/power. Keep the boost to 1.2bar, and totally stock is ok to thrash all day, everyday no problems.(he is also a d1 driver, so he has a good idea of what thrashing is:))

anyways, hope that helps a bit,

steve

[Roy]

Whilst a 3037 turbo is bigger then my TD06, i have been running it on my standard RB20 for over 15,000kms now, and my engine has just under 170,000kms...

Boost will be very dependant on the A/R of the exhaust housing you are running. Id be trying to get my hands on a 0.61 for the RB20...

I wouldnt be expecting 1.0bar until around 4500rpm with the 0.61 housing on a std RB20. And i would be hunting down some injectors and a new ECU with that turbo, otherwise you wont be able to reap all the benefits it could offer. Some cams and a good tune always help power output, delivery and boost repsonse

[Steve]

roy, I doubt it will be quite that bad, I know a guy who was running 0.73 on SR20 and it hit 1 bar just on 4000rpm.

but at the end of the day, I suppose it will be dependant on manifold, cams, and all the other supporting systems.

[beario]

hey lads...the a/r is .73..and the exhaust is roughly 3 inch from back of turbo to de cat and then 4 inch to the hks hyper back box...???

[Steve]

well bolt that sucker on, fit some injectors and get a tune - thats the only way you are going to know for sure - a new exhaust housing is around $500AUD if you buy it from the US, a little more expensive from Japan, thats IF you need to downsize. I am pretty sure that HKS recommend the 0.73 with the RB20 kit - should be nuts anyway.

please post up the results

steve

[Roy]

well bolt that sucker on, fit some injectors and get a tune - thats the only way you are going to know for sure

Listen to the man...be sure to let us know how it goes.

The HKS listings for RB20s i have seen all list the GT25 series and GT2835 as RB20 upgrades, the fact that i havent seen a listing for the 3037 suggests to me that they arent really intended for a std engine, thats why i thought go the smaller housings, but only guessing on the limited HKS catalgues i have seen.

[discopotato03]

I would imagine that this is the case because RB20 exhaust manifolds are flanged for the T3 pattern while most HKS GT30 exhaust housings use the T25/T28 flange pattern . HKS USA site gives most details of these turbos . If anyone is interested in selling one of these with the .73 exhaust and 52 trim compressor for a sensible price let me know (for an FJ20ET ) .