Jump to content
SAU Community

Recommended Posts

I reckon the delivery of the turbo plays a definite part in the ET, and the on-off responsiveness between gears in the trap speed and ET for sure. The G3 as Stao says has good 'rush' up top, but a little lazy in and out of gears (on stock manifold low mount I mean) and kind of like a light switch delivery in 1st and 2nd which makes juggling bog/wheelspin hard off the line.

And obviously driver experience at the strip :P

+1

It wasn't easy to get off the line- first run i bogged hard and the next I fried the tyres. I think I'm going to need a fair bit of seat time to get the launch right!

Yeh I think Luke's and my trap results are very effected by boost response between gears. Took the car for a drive the other night and tested that out, and I've got about half a second to a full second of lag between each gear change.

Block up BOV helps.

The launch won't affect you trap speeds much most 1-2mph the better you launch better 60ft you trap speed will be lower

But yes it will affect you et I think its for every 0.1 quicker off your 60ft it's 0.2 off your et

So you will need a 2.0 60ft and you will be in the 12.8 but proberly 113 or 114mph

Yeh I think Luke's and my trap results are very effected by boost response between gears. Took the car for a drive the other night and tested that out, and I've got about half a second to a full second of lag between each gear change.

SS2 FTW!!

comp.JPG

This is the latest G3 turbocharger. It has stepped down back to a 56T from 58. I've focused it on better throttle response and transition response.

The prototype about is built in ball bearing. It felt pretty good on road comes on boost with very light throttle. hitting the dyno again on Wednesday and see how it goes.

Yes it has stepped down to 56T. No point going for a 58T if majority don't have a setup and a engine for that extra power. This one was focused on throttle and transition response. It makes an great every day road turbocharger within the budget.

This casting is in steel as usual.

I'm dreaming of the day you trim down the turbine to something under 80.... I think that would work better for response again.

The sl2 wheel is 61mm with a mid 70s trim. You saw the response on that vs your ss2 when they were running the same compressor... Just do eeeet

Well it made 30kws difference in power with less boost compare to the L2 turbine. Also peeks boost at the exact same RPM which is pretty interesting (Do have slightly lower RPM to Boost ratio before that point, result overlay at page 351)

This turbo needs to be able to work internally gated, So reducing the trim on turbine end will probably hurt that. Small trimmed turbine might work ok on smaller SR and Rb20 engines, When you are bored of the SS1PU and ready for a high mount I can trim one for you to your recommendations.

You just need to tell me what housing to supply, as I will be buying the Tial housing soon.

At the moment I was going to buy a .64 suit GT28, but if you want me to get a GT30 spec housing just let me know. Yet the GT30 are 60mm 84 trim, so we might be better off using the .64 GT28 housing anyway so we can profile it up. The GT30 housing would need a sleeve which I am not too confident in doing.

Can you tell me the specs of your highflow turbine? From memory its a 60mm but different to whats in a G3?

Welcome to A Brand new all better and all mightier ATR43G3 turbocharger. The Older 58T version is now retired.
comp.JPG

This turbocharger have out performed the older profile of the G3 in both peek power and response. Both turbochargers had roller bearing cartridges installed.

Thin Yellow and Red (18psi) is the latest G3
Thick Yellow is the older 58T G3

This turbocharger stopped making power at 376rwkws @ 23psi.

atr43g376rwkw.jpg

atr43g3boost.jpg

Congratulations. That new turbos certainly do produces a wide spread curve, making 240rwkws @4000 rpms. It would be a hell lot of fun on road. Great to see the improvement stao. Good work. :thumbsup:

Stao,

Are these results comparable? Ie. your new setup is on an aftermarket highmount manifold and externally gated, did you test the old profile G3 on the same setup or is this new result vs the old stock manifold/internal wastegate result?

Highmount/external by looks, i want to see internal gate 56T vs 58T on stock manifold, thats what most people have/buy..

Also going back to the 56t, originally you where saying the 58t needed cams for more power from memory,

but going back to 56T and still giving samish results, have you actually run out of turbine flow?

cheers

darren

Edited by jet_r31

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now



  • Similar Content

  • Latest Posts

    • Hi All, New member here, I've joined to help my son with an issue that is truly doing our heads in. I'll start with a bit of an overview. Chris carried out some modifications to the engine to try and extract just a little extra power out of the motor and make it a bit more efficient. Previous to this work, the car already had an upgraded exhaust, increased boost up to 14psi, modified standard turbo to metal impellers and slightly oversized, upgraded fuel pump, been dyno-tuned at JEM, and some other bits n bobs like coil packs etc. Before the current mods it was making 236rwkw at 14psi but after the new mods it now makes 209rwkw at 14psi. The work he carried out is as follows, timing belt service, water pump replacement, return to sump radium catch can, had oem head rebuilt and machined 0.2mm, fitted Athena cut ring head gasket 1.2mm thick, arp 2000 head studs, added rear prp head drain, added an external wastegate 40mm turbosmart welded off the stock manifold and plumbed back into a 3in dump. The car has been on the dyno and apparently the ignition is working, fuel flow and fuel pressure is fine, injectors are fine, spark plugs are working fine, Maf is working, O2 sensor is working, TPs sensor is working, VCT is working, CAS is working, boost leak test showed no boost leaks, compression test first crank cold 135psi and got to 150psi across all cylinders once cranking, timing is confirmed at tdc with a dial gauge and the cam dots line up, no blockages in intercoolerm throttle body or pre-turbo intake, no blockages in exhaust, cat conveter or down pipe, turbo looks fine and spins and wastegate looks fine and is new. Soz for all the detail but after all this, it has been in 3 times for dyno and each time comes back stating it's not going to make power. After the first (or second, can't remember now) trip to dyno we did find the timing out by one tooth and this improved things, but it is still well down. Does anyone have any ideas?  Any replies much appreciated as we're just not sure of which direction to take this. Regards Rob (Chris's Dad).
    • That's just a gauge, with a certain amount of electronic damping, and no-one cares if it is timely-accurate. I'd hesitate to use it for an ECU MAP input without knowing that it was a nice signal. Responsive but smooth. Not laggy. Not lumpy.
    • Took the dirty BMW to an actual drag meet so I could do a legit full pass on a sticky enough track and had a quiet goal to try and beat my PB in the old R33 GTS25t The time to beat:  R33 on stock RB25, Internal gate GT3076R on stock manifold tuned to about 17psi on BP98 and running on drag tyres: F20 M135i with intake, dump pipe and MHD OTS Stage 1 tune on street tyres - didn't even drop the tyre pressure: Kinda similar, and kinda way different
    • Isn't there a fitting on the back of the balance tube? That's what the OEM boost gauge uses.
    • Getting a decent signal from all 6 throats is a challenge. I don't know for sure, but I suspect that the stock balance tube is not ideal for it. I have done it on an ALFA 4 cylinder (about 35 years ago, so don't ask for too many details). We drilled 4x holes in the manifold runners, put in some fittings and ran hoses to a decent sized (I think it was about 20mm diameter) pipe that ran the length of the inlet manifold. So, it was quite a decent volume. There is a "tuning" balance to be found between the volume of the common plenum on such a thing and the diameter of the pipes running from it to the runners. You need the volume to be large enough to damp out the sharp spikes in pressure signal you get as each runner gets sucked on by its cylinder, but not so large that it becomes too slow to respond to actual changes in MAP. And you need the hoses to be small enough to transmit the signal quickly, but not so small that they delay the signal. You might have to have more than one go at it, if there isn't any actual success based wisdom to be had here. Hopefully there is. Anyway, I would not do it on only a couple of cylinders. I would also not care about "permanently modifying a part". Just bloody drill holes and make stuff better. There is nothing sacred about any GTR unless it is a genuine museum piece that you shouldn't be modifying at all anyway.
×
×
  • Create New...