GTX2863R on SR20

[PL]

I did an SR20 last week with a GTX2863 (with 0.64 AR rear). S14 SR20DET in Datsun 1600 on Dyno Dynamics dyno running 98 RON fuel. Impressive little turbo that delivered exactly what I was expecting – significantly more power than the T28 with only a slight lag penalty. The impressive part is how much more power! We saw 230rwkw (= about 380 hp at crank) on 17psi from an S14 SR20 with stock cams.

Comparison based on other SR's I've tuned with std cams on same dyno (I use 15psi as my standard full boost figure):

std T28 = 200rwkw on 15psi, making 15psi at 3300 to 3500
GTX2863R = 230rwkw on 17psi, making 15psi at 3750
GT2871R (52t) = 215rwkw on 17psi, making 15psi at 4000 to 4300

What remains to be seen is how it performs once cams are fitted and what happens at higher boost levels. Cams traditionally give 20rwkw gain on ANY SR20. So that’d make 250rwkw on 17psi from this little beasty! That’s really worth talking about!

Unfortunately it didn’t respond particularly well to my trusty ball-n-spring boost control. It was spiking to nearly 20psi in order to maintain 17psi up top. So this limited our fun. This seems to be a common thing – the ball-n-spring valves are fine up to about 15psi. Above that you’ll always get a spike and it gets worse as boost increases. The spike is also worse on small turbos. That HKS GT3037 Pro S that I did awhile back was running a ball-n-spring system and the boost curve at 16psi was nearly perfect.

Looking at the compressor maps, these turbos should remain efficient at 25psi and more! But whether they have the airflow to keep up is another thing entirely.

Interested in anybody else's experiences with these turbos - and the "67" too...

Pete L

[TM_S13]

hum... nice stuff =)

[streetbike]

what exhaust manifold do you use on this setup ??

for the 2867 I will tell you how it will perform on a CA18 in a couple weeks

[PL]

He had a generic tube type stainless manifold on it. Doubt it made much difference but I don't have before and after figures on the manifold.

PL

[skylinegtrhr]

std T28 = 200rwkw on 15psi, making 15psi at 3300 to 3500
GTX2863R = 230rwkw on 17psi, making 15psi at 3750
GT2871R (52t) = 215rwkw on 17psi, making 15psi at 4000 to 4300
Pete L

Hi Pete I have two GT2868 Owen performance billet turbos with TIAL housing (external WG) waiting to be mount on cars, but these are project cars so who knows when they will roll out of workshop .

Did You drive this car on road? I'm interest do they have any "turbo hole", I mean do they make resistance to engine when it is off boost like these other turbos listed above (GT2871R but with bigger A/R is horrible to drive - like hand brake is You go off boost)? Can You compare it to GT2860RS "disco Potato"? I know that only turbo set up without any turbo hole is twin scroll set up which we install on our demo car,again thanks to Yours advice , but we are interested how this budget setup is working in real world.

[PL]

I didn't drive it but I'm assuming there'll still be a "hole". It's the same "hot" side as all the other "GT28" series turbos, so same restriction. It just has a better comp wheel. So I'd expect it to be slightly worse than the std "T28" turbo as far as response goes. But much better up top.

PL

[Adrian]

Thanks for the report and sharing your experience. Very good results. It's always a good thing to hear results from other tuners. On this way you don't have to try out everything on one's own.
Are the power-numbers measured at the wheels or at the crankshaft? Is it a standart block or a forged built? In the case of a standart block, are you don't worry about the internals (pistons, rods etc.). Especially if you add cams (= +20kw)? What do you think wher is the limit of the standart block in KW and Boost? In my eyes the standart engine can hold 380 crankshaft horspower, but for racetrack use it's better to leave it at 350hp at the crank.

[PL]

We tend to use kilowatts at the wheels (rwkw) around here. Funny how different areas use different measurements. Makes it hard to compare. To convert to crankshaft horsepower I just multiply those figures by 1.66. So 230rwkw = 380 hp at crank.

Naturally converting power at the wheels to power at the crank assumes a loss factor for both transmission and tyre/roller interface. Dyno Dynamics use 20% and that seems to usually add up reasonably well. Although this seems to be a favourite point to argue for many people. Then there's the fact that different brands of dynos read differently, and roller vs hub vs proper engine dynos. Whatever - they all get the job done one way or another and they all read differently. When I'm comparing power figures I always try to use the same dyno with the same setup to minimise any measurement errors. But in the end there will always be differences and the best data will be obtained by taking an average of results from vehicles using the same turbo. Eventually you get to know what to expect from each turbo on the dyno you use.

Regarding max power for std internals I'm in agreeance with your figures. I have no real proof though - the only way to really know is to get engines out there are see what breaks at what power level. I don't have the level of experience it takes to have multiple broken engines come back so I can examine the results. Even when they do come back broken it's often difficult to determine the cause of failure, although everyone is quick to jump to conclusions!

Probably the best example I have seen is a friend's S13 that I've been tuning for years now. It was a daily driven street car and the eventual configuration was making 265rwkw (so about 440hp at crank) on std internals. It went like that for ages and eventually at 100,000+ km he pulled it down and it only needed rings and bearings. But this is a street car, so it only ever sees bursts of full power. Now being built for 300rwkw. Now that's where std internals really become questionable!

I've done a few drift cars that are around the 220 - 240rwkw (365 - 400hp at crank) and they seem to survive quite well with no blow-ups that I'm aware of. But once again - drift is often just bursts of full throttle with longish rests in between. Drifters tend to have pretty low expectations for engine life too! "Yeah, popped another engine on the weekend - meh...).

Circuit cars are where I get conservative on the tune. If you're gonna run more than about 220rwkw then I like to see some serious attention paid to cooling systems and instrumentation/logging as the constant high boost use will stress everything a lot more than using it in bursts. They'll usually keep going if things like coolant temp, oil pressure and fuel pressure are kept in check. Most circuit racers who start using big power are smart enough to start with forged internals. But I'm rambling now...

PL

[mailman31090]

I know the post is old, but hey Pete I was wondering if you still have the map from the gtx2863 tune laying around. I'm new to the whole tuning thing so I'm trying to get everything together before the engine goes in. I'm using your sr20det timing map that you had on one of these threads. I just wanted to know if you had something more specific to my setup as far as fuel and timing goes for a basemap so I can turn the car on and go from there.

S14 sr20
gtx2863
z32 maf
650cc injectors deatschwerks
38mm tial wastegate
mishimoto z line ic
2.25 hot side
2.5 cold side
3in exhaust from turbo on back
everything else stock

[PL]

Hi,

Yeah, just email me direct pl <at> plmsdevelopments.com and I'll find you something suitable. I won't have something to suit the 650cc drilled injectors cos I refuse to use them, but I can easily scale one of my 550cc maps to suit. That should put you in a good place to start with.

Be interesting to see how it goes with external gate. Very well I suspect!

Since my original post I've done an S15 with 2863 and Poncams. Made just shy of 250rwkw (415hp at crank by my figures). At that power level boost was dropping off significantly from 20psi down to 16/17 psi up top.

PL

[mailman31090]

Alright thanks, I'll send you an email. Hopefully my greddy profec b can help me counteract boost dropping off. I'm also hoping for everything to go well with the external gate because the motor goes in next week lol.

Dang I just read on your page why not to use the drilled injectors. I have to use them for the time being though, they were all I could get my hands on at the time from a friend. Later down the road I'll switch them out. I'll post up my results when everything is said and done.

Those numbers from the s15 sound promising for atleast what I want . I'll post up my results when everything is said and done.

[PL]

You should be able to get better boost control and better power from using an external gate. I still don't quite understand why that is so, but I've seen it so many times now. A local tuner with a lot of experience once said to me that external gates are just better in every way and I didn't really believe him cos he couldn't back it up with solid theory. But he was spot on. External gates rule!

Yes, please post your results. Results good.

PL

PS: Get some cams in it. SR's love cams!

[speedemon]

good numbers im making 360whp @ 20psi with a not so clean tune I have a 2871r.84a/r 264 cams 740cc injectors 3in turbo back and 2in hot side and 3in after intercooler stock intake and manifold

[mailman31090]

Alright pl I finally got around to sending the email so I'll be looking forward to your maps. As far as cams I'm looking at the jwt s3 hl cams for around november. I'm really looking forwad to my results once I get a pair of those fitted in