Turbo Or Cams

[adam87]

hi guys

im new to the world of 25s. iv been searching through all the turbo related threads trying to decide which turbo to get. iv bougt it down to a hi flow, a 2871r or a 3071r. im only looking for about 300hp or maybe a little more. but as its in my s13 drift car i want it to be very responsive.

but then i got thinking about if i could keep my standard turbo. iv come up with these 2 options at the moment, which is more feesable?

option 1:

get a 2871r and run 15psi on the standard engine with the microtech.

option 2:

run a standard turbo or try find an r34 turbo cheap run 15psi and get a set of stage 1 cams and run an adjustable exhaust cam gear with the microtech

if the injectors max out before then well thats no big deal.

but really need some advice from people as im coming from a CA18 background

thanks

[DivHunter]

hi guys

im new to the world of 25s. iv been searching through all the turbo related threads trying to decide which turbo to get. iv bougt it down to a hi flow, a 2871r or a 3071r. im only looking for about 300hp or maybe a little more. but as its in my s13 drift car i want it to be very responsive.

but then i got thinking about if i could keep my standard turbo. iv come up with these 2 options at the moment, which is more feesable?

option 1:

get a 2871r and run 15psi on the standard engine with the microtech.

option 2:

run a standard turbo or try find an r34 turbo cheap run 15psi and get a set of stage 1 cams and run an adjustable exhaust cam gear with the microtech

if the injectors max out before then well thats no big deal.

but really need some advice from people as im coming from a CA18 background

thanks

I wouldn't run a standard turbo at 15psi and I'd say that turbo before cams would be the way to go in which case, there is heaps of info here about different turbos on the RB25.

[stolen_s15]

All the info you need is in the rb25 turbo upgrade thread stickied in this section (forced induction). Have a look at what people are using to make different power levels.

[Sheng]

Mate, as said before, you dont wanna run stock turbo@ 15psi, go browse through the rb25 turbo upgrade in the forced induction section, you will know whats good whats not

[adam87]

well thats pretty much answered my question.

iv read every thread about which turbo etc thats why im pretty certain on going a 2871r.

just didnt know to what extent you could push the standard one

[Dale FZ1]

If you want ~ 300rwhp, then first port of call is the fuel supply. A suitably sized pump, (either Nismo or an 040 Bosch) and injectors are VERY necessary in my view/experience.

I don't know of anyone personally who's gone the route of std turbo + cam upgrade, but given the generally fragile nature of the ceramic stock turbine would not suggest it to be the "best" way to go. Sure you will improve the mass-flow throughput of your engine, but you're pretty much limited to a boost increase up to ~ 10psi which is OK but not likely to get you there.

On the issue of 2871 and 3071 there has been plenty of discussion and a few different combinations tried out. To be honest I don't think that any of them have been bad, just a little different.

Basically all of the 2871 and 3071 combinations that use at T3 flanged turbine housing will use a modified OEM / OEM copy, except for one which will use the GT30 IW housing. That GT30 turbine combo is a different animal, and if you search you will find that we are waiting for the results of one of our members.

The other hybrid type setups, which are a marriage of impellers and housings not originally designed or intended to work together, do actually work quite ok. My particular 48T 2871 high flow hybrid runs the stock RB25 housings both sides, and does a fairly effortless 300rwhp but I don't expect much more. Response is very little different from stock and it is a good upgrade.

A logical step up from that is the 3071 hybrid which uses a 56T compressor and one of two trim sizes of a cropped 56.5mm GT30 turbine that will not accept the true GT30 turbine housing. There are a couple of sellers who marry up the R34/VG30 turbine housing (or copy) which is basically just a slightly larger A/R version of the RB25 housing. The bigger turbine rotor + bigger A/R allows better mass flow and hence higher engine power but checking back to back that spec vs mine the difference does not become pronounced until >5000rpm.

Another unit to consider is the HKS GT-RS which is essentially a 52T 2871 with a properly matched T3 flanged housing to suit the GT28 turbine - something that Garrett does not supply to suit Skylines. The SR20 runners with T25 flange specs are better catered for in that respect. On a $$ for $$ basis, the GT-RS is well worth a look because you have a bolt on kit and nothing else to change. And they perform very well. Search for a thread by Al, and you might be surprised what one of those can do.

[stolen_s15]

I saw you reading the thread for ages with post yet dale, as expected you were writing a mini essay! Very helpful though, as always.

[adam87]

If you want ~ 300rwhp, then first port of call is the fuel supply. A suitably sized pump, (either Nismo or an 040 Bosch) and injectors are VERY necessary in my view/experience.

I don't know of anyone personally who's gone the route of std turbo + cam upgrade, but given the generally fragile nature of the ceramic stock turbine would not suggest it to be the "best" way to go. Sure you will improve the mass-flow throughput of your engine, but you're pretty much limited to a boost increase up to ~ 10psi which is OK but not likely to get you there.

On the issue of 2871 and 3071 there has been plenty of discussion and a few different combinations tried out. To be honest I don't think that any of them have been bad, just a little different.

Basically all of the 2871 and 3071 combinations that use at T3 flanged turbine housing will use a modified OEM / OEM copy, except for one which will use the GT30 IW housing. That GT30 turbine combo is a different animal, and if you search you will find that we are waiting for the results of one of our members.

The other hybrid type setups, which are a marriage of impellers and housings not originally designed or intended to work together, do actually work quite ok. My particular 48T 2871 high flow hybrid runs the stock RB25 housings both sides, and does a fairly effortless 300rwhp but I don't expect much more. Response is very little different from stock and it is a good upgrade.

A logical step up from that is the 3071 hybrid which uses a 56T compressor and one of two trim sizes of a cropped 56.5mm GT30 turbine that will not accept the true GT30 turbine housing. There are a couple of sellers who marry up the R34/VG30 turbine housing (or copy) which is basically just a slightly larger A/R version of the RB25 housing. The bigger turbine rotor + bigger A/R allows better mass flow and hence higher engine power but checking back to back that spec vs mine the difference does not become pronounced until >5000rpm.

Another unit to consider is the HKS GT-RS which is essentially a 52T 2871 with a properly matched T3 flanged housing to suit the GT28 turbine - something that Garrett does not supply to suit Skylines. The SR20 runners with T25 flange specs are better catered for in that respect. On a $$ for $$ basis, the GT-RS is well worth a look because you have a bolt on kit and nothing else to change. And they perform very well. Search for a thread by Al, and you might be surprised what one of those can do.

thanks for that. very helpful. i was originally thinking a kkr430 but then after reading a few things i got that out of my head quickly. just looking at nengun at the actual HKS gtrs kit. its about 2200. does anyone else in aus do it at a similar price. its alot more than i wanted to spend but id say it will be the safest and best option.

but i have seen HPIAB now does the equivalent of a HKS gtrs. are these the ones your talking about?

Edited November 29, 2007 by adam87

[BHDave]

The hpiab ones will be a 2871 with a reground nissan IW housing (as metioned in dales thread). The genuine article is a better option, but ultimately it comes down to what you want to pay.

The nengun price is ex GST and Duty. You are running the gammit of customs and potentially will be stung for an extra 2-300 if you get caught.

[R31Nismoid]

HKS2535 if you want response, and around 220rwkw

The GT-RS is larger than that, less response

[RB30-POWER]

apparently there is a noob on this site that made over 300rwkw with stock cams and coils

dunno if i believe him but i would go turbo first. 300hp is nothing really, walk in the park for rb25, focus on boltons and you will get best bang for your buck.

[wizlb]

I have 261rwkw and this is what I had to do.

But if you want 300 do will need a different turbo.

Boost control

Apexi PFC

Split dump pipe

3" hi flow cat

Fuel 255 Warbro

Z32 Air Flow Meter

Greddy Cams Adjectable

Hi flow turbo GTT34/ Z30

Fuel Reg

FMIC Cheap PO

To get too 300 just add a better turbo.

JUst search 300 RWKW ad you will see which turbo they are using

[R31Nismoid]

apparently there is a noob on this site that made over 300rwkw with stock cams and coils

dunno if i believe him but i would go turbo first. 300hp is nothing really, walk in the park for rb25, focus on boltons and you will get best bang for your buck.

lol, i'll see that and raise you to 369rwkw stock cams, stock coils, stock basically everything (bar bottom end)

[TekniqTuning]

TURBO 1ST, t67 external, good response, still capable of good power