76 replies to this topic

[ghand]

Well having just got used to my stage 4 spending three weekends on my own and one with a big bike on VX roads you must be a lot better driver than me to want more If you have already got the thing it has to go on, that's what you bought it for. You could always go back if not happy and sell it on.

[Bumblebee]

If you read my previous posts I'm not wanting more power I agree 300hp is fast enough, for me anyway

[ghand]

If you read my previous posts I'm not wanting more power I agree 300hp is fast enough, for me anyway

Still has to go on having bought it, what have you to loose? What costs are involved do you know.

[Claws]

I'd be inclined to try a Siztenboots map first, he has invested quite a lot of time, effort and enthusiasm into developing his map and understanding the standard ECU. Then I would go standalone and the Gt28

[mbes2]

Not as if a piston will go pop :-p

[Bumblebee]

If you read my previous posts I'm not wanting more power I agree 300hp is fast enough, for me anyway

Still has to go on having bought it, what have you to loose? What costs are involved do you know.

To go for more power? If so an Engine rebuild

[siztenboots]

Not as if a piston will go pop :-p

any pictures of the top of the piston to understand the cause

[FLD]

 

 

Compound charging is the only answer.

 

No its not.  VNT or VGT can give boost at tickover and then right through the rev-range.  For example, Geoff Kershaw runs a twin VNT turbo sierra in hill climbs and this has 3psi at tickover.

 

 

VNT will give you the power to drive the compressor to where you want it but for a road car finding a map that will produce a 2:1 PR from 1000 - 7000 rpm is going to be very hard. Holset/CTT maps are the widest there are and the calcs I did on a 2.2 would only get from 3000 - 7000, one of the HBLS wheels may have worked but they don't do them small and need to be Titanium to take the stresses.

 

 

From what I did some years ago you need to run an external wastegate as well as the VGT/VNT system.  This gives the wider range of control but as you say finding a VGT small enough would be the problem.  I used a VNT28 (I think) with a T3 compressor wheel and a Rayjay external wastegate.  Hit boost just above tickover and ran up to 28lb.

[ghand]

If you read my previous posts I'm not wanting more power I agree 300hp is fast enough, for me anyway

Still has to go on having bought it, what have you to loose? What costs are involved do you know.

To go for more power? If so an Engine rebuild

The cost of fitting to try it, then re fitting if your not happy.

[Bumblebee]

I'm not sure what it would cost to fit it

[Bumblebee]

.

Edited by Bumblebee, 02 October 2013 - 10:21 AM.

[GeorgeBC]

I bet it doesn't use a v clamp so you will have to modify your exhaust which would be pointless on a 2.5nch system. Probably have to modify/make new heat shields. Seems like you have to jump in both feet or don't bother at all especially if you are paying someone else to do the work.

[TFD]

My experience with these turbo's on a Nissan SR20DET engine (2.0 l aswel as the Z20).

 

Ran a GT2871R .86 on my SR20 and it was laggy. Full boost at 4200 rpm and kickin in hard. I would never put this one on my VX eventhough the .2 more displacement. A .64 housing would be better. 

Will post dynosheet tonight. Ran 350 whp (400bhp) at 1.3 bar of boost

 

If you want 300bhp sell the GT2871R and buy the GT2860RS of the newer GTX2860RS is my advice. Smaller turbine for faster spoolup.

I'm going for this turbo on my 2.2 VX cause my mate ran it on his SR20 and look at de dyno:

 

This on a 2.0 Mazda MX-5:

GT2860RS .64 housing at 10psi pushing 283 whp (310ish bhp).

 

This is the line I like on a dynosheet for something small like a VX.... allmost SC like ....

 

Anyway, my $0.02

 

Good luck with your choice.

[TFD]

Cant edit last post...

 

This one is a better one:

@ 8psi a larger turbo will drop IAT compared to K04's pushing 20 psi or so while making the same power. Less heat = good.

[Nev]

 

 

 

Compound charging is the only answer.

 

No its not.  VNT or VGT can give boost at tickover and then right through the rev-range.  For example, Geoff Kershaw runs a twin VNT turbo sierra in hill climbs and this has 3psi at tickover.

 

 

VNT will give you the power to drive the compressor to where you want it but for a road car finding a map that will produce a 2:1 PR from 1000 - 7000 rpm is going to be very hard. Holset/CTT maps are the widest there are and the calcs I did on a 2.2 would only get from 3000 - 7000, one of the HBLS wheels may have worked but they don't do them small and need to be Titanium to take the stresses.

 

 

From what I did some years ago you need to run an external wastegate as well as the VGT/VNT system.  This gives the wider range of control but as you say finding a VGT small enough would be the problem.  I used a VNT28 (I think) with a T3 compressor wheel and a Rayjay external wastegate.  Hit boost just above tickover and ran up to 28lb.

 

 

Jesus, 28 Lb of boost turns a VX220 into an Excocet, more than either Aimy or I could cope with.

[slindborg]

Depends if the 28lbs is restriction or flowing

[danger7]

Hi Aimy,

 

I'm not on the org so much these days, but I see your interested in potentially going the route of a GT2871RS, i installed a GT2871 around 5 years ago, my VX has been continually remapped during this time, with upgrades to improve driveability, fuel consumption and response. Its fair to say there are inherent restrictions with a GT2871RS and that is the lag, we have improved it dramatically but its still 3,800 rpm and 0.9 bar before anything starts to get interesting. The current power is not a peek value (354 bhp/478 Nm at 4850 rpm - 1.48 bar boost max) but its a good driveable balance, higher is a waste of time imho (sorry Nev ) for circuit use, which is what I developed the car for mainly when I get the time.

 

Owen developments are the ONLY people I would buy a GT2871RS from (speak with Kevin for advice Aimy nice guy and very helpful), currently fitted is the second unit which has several upgrades over an off the shelf unit, steel cage, modified actuator and built as a blue brinted and balanced turbo from scratch.

 

The Air Mass Meter is a much larger unit fitted to mine which helps with boost recalculations and manages lag much better, you'll have to have install a dump valve and a modified exhaust manifold and here's an important bit. Heat distortion of the manifold is a problem - I have suffered warped manifolds a time or two (at the National the VX sounded like a tractor) and the only way we could restrict is to go to larger bolt diameters for bolting the flange (they creep and the gasket blows), which means retapping the threads on the turbo and exhaust flange, the gasket material is also important (we use a special material higher temperture resistance).

 

Heat soak in the engine bay is also much much more than standard (anyone see mine will have seen the slots in the back of the clam to help air flow) the undertray has been cut up and a bigger chimney helps cool things a bit, the piping and hoses are lagged and the whole supply piping to the charge cooler in and outtakes are aluminium with Samco connections. Exhaust is 3" all the way through and essential.

 

Intake manifold reworked slightly wider and throttle body is wider in diameter by 3mm , injectors biggest which can be installed, secondary fuel pump and swirl pot a must and aslo braided fuel lines.

 

Racelogic TC a useful addition with the GT2871 as it can get to be a bit much in the wet

 

Hope this made sense  - happy modding

 

Regards

Ian

[siztenboots]

Depends if the 28lbs is restriction or flowing

definitely

[siztenboots]

there will be some new stuff coming from Owen developments , here's a sneak preview
 

 

[TFD]

That looks good. GT28-like chargers fitting the OEM manifold would be great to keep things simple fittingwise.