Turbo Choice - Amateur Track Setup

[Redsuns88]

Hello there,

Popped my stock turbo lately and thought why not.. lets build a amateur setup for a hillclimbs and sprints/circuit.

i am aiming to base my car around response/power

Yes i have a SR20DET and i am in the midsts of deciding what turbo first before all other supporting mods.

originally i wanted a HKS2530 internally gated with a hks 14psi actuator..

but prices of a 2530 seem to be abit too far to reach. so i have to decided to use garrett turbos either a GT2860RS or a GT2817R with a .86 exhaust i think

I was leaning towards a GT2860RS as i think "i maybe wrong" but closest spec to the HKS 2530

was speaking to someone who knew their turbos and they was suggesting i choose the GT2817R with a .86 rear housing or exhaust as it is abit more "laggy" then the .64 but for track work it wont have any issues compared to the .64 where that was mainly based for street.

so now i am unsure what turbo to choose from. maybe you guru's will be able to help me choose. I dont plan on working the internals just yet, i just want to focus on maybe alittle on the head and allowing oil to flow smoothly without it being jerky, With the usual rocker stoppers, oil cooler, fmic, EBC, bosch 044 and maybe a fuel reg but i dont think the fuel reg is really needed unless proper ecu work and such.

As for the turbo i want it low mounted, was considering a 6boost manifold but yet was thinking stock would prolly be the best way to go. aiming for response and power do not want laggy or silly turbo suggestions please

please tell me what you think,

Cheers.

[discopotato03]

All BS aside the GT2860RS is a really good practical turbocharger for a road and track two liter four cylinder .

It's prototype was a club race turbo for an MX5 BP18 Mazda turbo engine .

I ran one on an FJ20ET and it was really good for the road .

It's easy to get carried away by the must have 400 Hp/300Kw train of thought but its too much IMO for a nice street car .

The Disco Potato GT2860RS turbo was designed to be responsive without being restrictive on the exhaust side which is exactly what you want in a street/club race application .

Technically a GT2860RS is VERY similar to the HKS spec Garret "GT2530" , the only difference being the compressor wheel which is still the same 60.1 mm OD but 62 rather than 63 trim with greater exducer tip height .

The GT2860RS uses the same 0.60 A/R T04B compressor housing as many single app GT2530's but without the smaller inlet barb bolted on machined snout .

The real difference is the 0.86 vs 0.64 A/R turbine housing . Neither of these turbos needs the smaller 0.64 A/R turbine housing on 2L and up 4's as they "spool" quite well with the larger one .

My old FJ20ET got positive pressure at 15-1600 revs in upper gears and was easily capable of hauling my Bluebird around roundabouts at slow speeds in 3rd gear .

Turbos like these are whats needed to get torque numbers in foot pounds similar to horse power numbers , if you can get up around 300+ ft/lbs of torque it feels real punchy . 300 odd Hp may not sound like a lot but from memory R32 GTRs were quoted as having ~ 290 in std form - from memory .

Regardless torque is what you want and you need it usable in every day driving .

What you will notice with the DP turbo is how much extra low end and light to medium load ignition advance you can use without detonation . Going from a std RB20 ceramic BB turbo to the DP I was able to screw in an extra 6-8 degrees of timing which really picked up the bottom end torque and throttle response .

I really don't think you need an 044 pump as these kinds of power levels , I used a 975 at the time and even it may have been overkill . If you use larger than std injectors and a programmable computer the std FPR should be fine if it's in good condition .

Do a search for an article from the June 2003 edition of Sport Compact Car Magazine , Google "Project Nissan Silvia Part II Behold the Potato" .

Basically a USDM S13 with a JDM SR20DET fitted then the DP turbo upgrade . Good pics and the usual wowza story .

I had the ear of JC from Garrett in the US at the time and he couldn't speak highly enough of that turbo .

I went to Brett at GCG Turbos with the part numbers and he brought the first batch of them into Australia about 5 years ago .

I know what I'd do , cheers A .

[Redsuns88]

Thanks for that i didnt quite understand what you are saying witht he .64 housing.. i should not go with it or choose the .84 rear housing on the GT28RS?

i actually plan on running mild psi through it. nthing crazy like 20psi or anything like actually intened on running 14 - 16 psi maybe 18 if engine can handle it.

still at that PSI would the GT28RS still respond well or little overkill?

:S still laerning these things

[STATUS]

forget the 0.86 2871's i have used a few and they are pretty average, require 20-22psi to make decent power over the smaller housings.. even then the extra top end is not worth the lag...

Put simply we had a GT2835 ext gate kit (HKS) making 288rwkw, the GT2871R 0.86 was laggier and was 15-20rwkw shy on the top end aswell....

Best track day turbo for a SR20 is a GT2860RS with decent cams to extend the top end, a SR20 with GT2860RS should pull 220-235rwkw on a std bottom ended but cammed engine no worries at sensible boost.

Edited June 20, 2009 by URAS

[Redsuns88]

sensible boosting being 14/15psi or 18ish?

[discopotato03]

Personally I don't equate boost pressure to power because to my way of thinking its how much air you get to burn that tells the story . Really its a case of the better you can make the manifolds and head breathe the lesser the pressure you need to get the air in .

With turbine housings Garrett makes two sizes for their GT28 turbine based turbos 0.64 A/R and 0.86 A/R .

JC , no another one , cooked up the original DP GT2860RS and he amongst other at Garrett America will tell you that it's not a real DP if you use the smaller 0.64 A/R turbine housing . The whole idea of this turbocharger was to have good response and minimul exhaust restriction and they work well provided the mixtures and timing are tuned to suit it .

The mob at Silvia net don't always agree and I get the feeling that they may be trying to use these turbos on SR20DET's with std computers tuned around a more restrictive turbine and housing ie the S whatever BB turbo .

AJ from the then Road and Rally Center fabricated an exhaust manifold for my FJ20 because they have T3 flanged ones std and there is no such thing as a T3 flanged GT28 0.86 A/R turbine housing .

The runners in that manifold were not real big diameter wise , may have been 1.25"/32mm bore but it worked well .

I also think the Silvia mob are scared of the 0.86 A/R number because it is a reasonably big ratio but in a small/medium family of of turbines ie T2/25/28 . Honestly if you had say a VL Turbos 0.63 A/R T3 turbine housing next to a GT28 0.86 A/R one you wouldn't think the 0.86 GT28 one was huge . Its a very clever combination of a larger tip height low blade count , and open bladed turbine , in a large ratio medium sized family of turbine housing .

From memory the only OEM GT28 turbo that used this kind of 0.86 A/R turbine housing was the GTiR spec SR20DETs turbo . Don't try and pinch one of those housings BTW because it used a slightly different family 10 bladed 79 trim turbine , the one in the GT2530/GT2860RS/GT2871R's is 76 trim .

Also Garrett and HKS opted for the T04B compressor housing because it uses a larger diameter back plate meaning a larger diffuser diameter which effectively widens the islands on the compressor map . It's the combination of this and the larger turbine housing (for a GT28BB) that make the GT2860RS such a wide ranging turbocharger - suitable for engines I guess in the 1600 - 2400 cc range depending on the intended use .

I initially used electronic boost control (Autronic SMC) but found the std actuator worked pretty good as it was . Just make sure that it has sufficient pre load to keep the gate shut until the boost comes up or it'll be a laggy dog as any turbo would be .

And lastly with the GT2871R's , they can be laggy dogs if they have the largest 56 trim compressor fitted - and with the 0.86 A/R turbine housing . The 71.1mm compressor wheel is available in 48 52 and 56 trims and I reckon the most common GT2871R , had to be the 56T one didn't it , tends to be a laggy dog . I believe the problem is that the 56T 71.1mm compressor is good for maybe 460-480 Hp but the GT28 turbine is struggling much past ~360-380 Hp . Imo too much compressor for the turbine .

The smaller 48 and 52T compressors seem to work better but its often difficult to get people to understand that less than the biggest is a better match for that turbine .

Now for the last few who haven't fallen asleep .

It is absolutely critical not to oversize a turbocharger when using production gearbox/diff ratios because the power (torque) delivery can get peaky and you end up falling off the boost curve or looking for more revs up near the red line .

An engine that gets going about a third of the way up the rev range and has real punchy stump pulling torque is more than happy to pull your typical tallish and reasonably wide gearbox ratios in style . If it takes half or more of the available rev range just to begin to find some boost and torque you virtually have to go to the red line every gear just to keep the turbo on the boil . The bloke with the properly sized turbo well get you out of the tight bends every time .

So now its your call , GT2860RS 0.86 A/R would be my first choice . Read that article in SCC , I think they tell you that everyone that had a ride in that S13 was highly impressed at how well it went and how well mannered it was .

Cheers A .

Edited June 20, 2009 by discopotato03

[discopotato03]

I think this link is a bit buggy but try it anyway .

http://www.modified.com/projectcars/0306sc...rt_2/index.html

Cheers A .

[STATUS]

Personally I don't equate boost pressure to power because to my way of thinking its how much air you get to burn that tells the story . Really its a case of the better you can make the manifolds and head breathe the lesser the pressure you need to get the air in .

With turbine housings Garrett makes two sizes for their GT28 turbine based turbos 0.64 A/R and 0.86 A/R .

JC , no another one , cooked up the original DP GT2860RS and he amongst other at Garrett America will tell you that it's not a real DP if you use the smaller 0.64 A/R turbine housing . The whole idea of this turbocharger was to have good response and minimul exhaust restriction and they work well provided the mixtures and timing are tuned to suit it .

The mob at Silvia net don't always agree and I get the feeling that they may be trying to use these turbos on SR20DET's with std computers tuned around a more restrictive turbine and housing ie the S whatever BB turbo .

AJ from the then Road and Rally Center fabricated an exhaust manifold for my FJ20 because they have T3 flanged ones std and there is no such thing as a T3 flanged GT28 0.86 A/R turbine housing .

The runners in that manifold were not real big diameter wise , may have been 1.25"/32mm bore but it worked well .

I also think the Silvia mob are scared of the 0.86 A/R number because it is a reasonably big ratio but in a small/medium family of of turbines ie T2/25/28 . Honestly if you had say a VL Turbos 0.63 A/R T3 turbine housing next to a GT28 0.86 A/R one you wouldn't think the 0.86 GT28 one was huge . Its a very clever combination of a larger tip height low blade count , and open bladed turbine , in a large ratio medium sized family of turbine housing .

From memory the only OEM GT28 turbo that used this kind of 0.86 A/R turbine housing was the GTiR spec SR20DETs turbo . Don't try and pinch one of those housings BTW because it used a slightly different family 10 bladed 79 trim turbine , the one in the GT2530/GT2860RS/GT2871R's is 76 trim .

Also Garrett and HKS opted for the T04B compressor housing because it uses a larger diameter back plate meaning a larger diffuser diameter which effectively widens the islands on the compressor map . It's the combination of this and the larger turbine housing (for a GT28BB) that make the GT2860RS such a wide ranging turbocharger - suitable for engines I guess in the 1600 - 2400 cc range depending on the intended use .

I initially used electronic boost control (Autronic SMC) but found the std actuator worked pretty good as it was . Just make sure that it has sufficient pre load to keep the gate shut until the boost comes up or it'll be a laggy dog as any turbo would be .

And lastly with the GT2871R's , they can be laggy dogs if they have the largest 56 trim compressor fitted - and with the 0.86 A/R turbine housing . The 71.1mm compressor wheel is available in 48 52 and 56 trims and I reckon the most common GT2871R , had to be the 56T one didn't it , tends to be a laggy dog . I believe the problem is that the 56T 71.1mm compressor is good for maybe 460-480 Hp but the GT28 turbine is struggling much past ~360-380 Hp . Imo too much compressor for the turbine .

The smaller 48 and 52T compressors seem to work better but its often difficult to get people to understand that less than the biggest is a better match for that turbine .

Now for the last few who haven't fallen asleep .

It is absolutely critical not to oversize a turbocharger when using production gearbox/diff ratios because the power (torque) delivery can get peaky and you end up falling off the boost curve or looking for more revs up near the red line .

An engine that gets going about a third of the way up the rev range and has real punchy stump pulling torque is more than happy to pull your typical tallish and reasonably wide gearbox ratios in style . If it takes half or more of the available rev range just to begin to find some boost and torque you virtually have to go to the red line every gear just to keep the turbo on the boil . The bloke with the properly sized turbo well get you out of the tight bends every time .

So now its your call , GT2860RS 0.86 A/R would be my first choice . Read that article in SCC , I think they tell you that everyone that had a ride in that S13 was highly impressed at how well it went and how well mannered it was .

Cheers A .

I reckon your right.

REDSUN attached is a gt2871r 0.86 56t vs GT2860RS 0.86 at the same boost.

[Redsuns88]

oh ok thanks!

so its a GT2860RS with a .86 or .64 trim?

:S

[juggernaut1]

.86 A/R (not trim)

Edited June 21, 2009 by juggernaut1

[Redsuns88]

pretty sure i wrote housing..

ah well thanks for picking it up.