Chasing 350-400rwhp, But With Much Less Lag. Advice Please?

[SoFreshSoClean]

Hi all,

Just bought my workmates R33, currently running a cheap chinese turbo and making a very laggy 350rwhp on 18psi (doesnt start boosting until 5k rpm).

I am looking to replace the turbo and basically 'increase the area under the curve', this is a street car so I am after maximum response rather than all out power.

This is the engine as is now:

.

-3 inch exhaust/4 inch cat

-pod filter

-FMIC

-Greddy ebc

-PowerFC

-Aftermarket inlet manifold/80mm throttle body (brand unknown)

-Tubular exhaust manifold(again unknown)

-Bosch fuel pump (044 or 040 I can't remember)

-Big but very average performing turbo

I would be chasing full boost between 3-4k, I'm guessing a GT3076 is the way to go, and would that bolt straight up to the manifold I have on now? Sorry if I'm asking unasnwerable questions, I'm just trying to go into this prepared.

[zebra]

as long as the manifold flange is t3 than yes a 3076 will go straight, bout you will need water lines and a new dump pipe.....also the way that fuel rail is setup looks very dodge...maybe its just the pic.

1 question though..do you want 350rwhp or 400? if you only want 350 than go a 3071 if 400 than go a 3076

[R31Nismoid]

^ Exactly as above

GT3071 - 350rwhp-370rwhp

GT3076 - 400rwhp-430rwhp

You just need to decide which it is you want and dont deal.

It should bolt to the manifold you have now. Is it externally gated?

[SoFreshSoClean]

Chances are the fuel rail setup is dodge.. I wont go into details but the workshop that tuned it had it using 30l/100km (ie 200kms per tank) until it was re-tuned by hyperdrive.

External gate means screamer pipe, right? If so then no, its internally gated.

What rpm does a GT3071 generally produce full boost? It's an otherwise standard motor so probably not worth chasing the extra HP in exchange for bent rods...

[zebra]

i dont see an internal wastegate actuator so i dare say its externally gated, it would just be plumbed back.

as for full boost id say approx 3500...but i depends on the state of tune the exhaust manifold, the exhaust etc etc

[bradsm87]

Chances are the fuel rail setup is dodge.. I wont go into details but the workshop that tuned it had it using 30l/100km (ie 200kms per tank) until it was re-tuned by hyperdrive.

External gate means screamer pipe, right? If so then no, its internally gated.

What rpm does a GT3071 generally produce full boost? It's an otherwise standard motor so probably not worth chasing the extra HP in exchange for bent rods...

The GT3076R is more efficient over a wider flow range than the 3071.

I'd recommend the less-common GT3076R 52 Trim .82. Should make full boost at 3500 and pull HARD from then onwards.

The 52 Trim will be more responsive than the more common 56 Trim.

[SoFreshSoClean]

The GT3076R is more efficient over a wider flow range than the 3071.

I'd recommend the less-common GT3076R 52 Trim .82. Should make full boost at 3500 and pull HARD from then onwards.

The 52 Trim will be more responsive than the more common 56 Trim.

Sounds interesting! Full boost by 3500 AND 400rwhp? Having my cake and eating it too would be nice!

[skylinecouple]

I have the 3071 with .82 housing and can honestly say it spools like my old GCG hi-flow. I would strongly suggest you learn to tune the ignition side of the PFC before you give up on the turbo you have. I can not stress enough how even the best tuners will not do a truly thorough job in the low load areas. Especially coming on to boost and conseqently your response in this area will suffer badly. It has taken me some time to perfect my tune and I have done a much better job than any top tuner even the ones I recommend to others. Your tuner will have no doubt tuned the fueling to a safe level so just work on the ignition.

If then your fed up with trying to make it work by all means the 3071 or 3076 are the perfect choice. If I did it again it would be the 3076 just for the top end. I believe with the 3076 the difference in lag would be very little.

[JonnoHR31]

yer my last hyperdrive tune had no where near enough timing below 4000rpm, was rather pathetic for such a highly regarded workshop. i'm in perth and can tune pfc's if you want to try and get more response out of your current turbo as skylinecouple said

[hypergear]

run a GT2871R 52T CHRA in a .86 OEM Bolt patterned T28 turbine housing and .60 comp housing. Full boost at 3000RPM and max out around 260rwkws.

[krzysiu]

I'd recommend the less-common GT3076R 52 Trim .82. Should make full boost at 3500 and pull HARD from then

I can vouch for that haha

[GTScotT]

I can vouch for that haha

I thought you were running a 56T mate? Sounds like you need to post up your part number lol

[XRATED]

Have a look at precision turbo's from the US. The billet comp wheel, plain bearing turbo's are very well priced.

J.

[SoFreshSoClean]

I have the 3071 with .82 housing and can honestly say it spools like my old GCG hi-flow. I would strongly suggest you learn to tune the ignition side of the PFC before you give up on the turbo you have. I can not stress enough how even the best tuners will not do a truly thorough job in the low load areas. Especially coming on to boost and conseqently your response in this area will suffer badly. It has taken me some time to perfect my tune and I have done a much better job than any top tuner even the ones I recommend to others. Your tuner will have no doubt tuned the fueling to a safe level so just work on the ignition.

If then your fed up with trying to make it work by all means the 3071 or 3076 are the perfect choice. If I did it again it would be the 3076 just for the top end. I believe with the 3076 the difference in lag would be very little.

But surely a tune cannot make that much difference to spool times? Literally, in first gear I hit boost at 6k, immediately run out of revs, change to 2nd, starts going good again at 5k when again I run out of revs.. third gear is when it really comes on and goes hard but it's useless for a street car because those speeds are illegal anyway.

[R31Nismoid]

A tune is the be all and end all.

Get the tune wrong the entire setup can be crap. Tuning i call setting cam timing, timing/fuel across the map etc etc.

I don't know about you but im certainly seeing boost before 5k in 2nd with my RB26/lowmount combo, you need to watch your boost gauge closer as it should be much closer to spooling in reference to 3rd/4th gear etc.

Obviously later subjectively as it very much depends on the load the engine is under at that time, where in the map/cells it is etc etc.

[SoFreshSoClean]

Well the fact remains that I have a useable powerband of about 1800rpm, I doubt a retune is going to give me an extra 2000rpm to play with.

[JonnoHR31]

you'd be surprised. like i said i can look at your tune for you. PM me if your interested

[R31Nismoid]

Well the fact remains that I have a useable powerband of about 1800rpm, I doubt a retune is going to give me an extra 2000rpm to play with.

So what?

Fact is, and we've told you, there can be signifigant gains from a good tune vs a shit one.

There is NO way a car with a mild turbo should be taking until 5,000rpm in 2nd to make solid boost.

Take your car to a flat piece of road. Roll from 20km/h and see when boost comes on.

[SoFreshSoClean]

So what?

Fact is, and we've told you, there can be signifigant gains from a good tune vs a shit one.

There is NO way a car with a mild turbo should be taking until 5,000rpm in 2nd to make solid boost.

Take your car to a flat piece of road. Roll from 20km/h and see when boost comes on.

Haha alright I'll bite, I'll get the tune looked at . I also have a Greddy profec B spec II.. is there much scope for that to be set up wrong too? Surely a big workshop wouldn't have got that wrong?

[JonnoHR31]

yes could definately be setup wrong. they should have it right but once again when andy at hyperdrive set myne up it didnt have anywhere near enough gain, maybe not everyone wants it to come on as hard and fast as possible...