Turbo Sizing Vs Response/spool Time.

[nicksamaniac]

1stly, thanks for all the feedback!

2nd, yes you are correct, I wrote in the post incorrectly, it's 6' extra overlap not separation, I closed the gap- this gave about 500-600rpm lower boost threshold.

3rd, the reason I have gone the RB route is because

A, it's awesome!

B, it came with the RB in it (rb30s)

The other versions use different setup and parts.

C, it makes it more car like with the broader power band instead of like a truck that revs to 3500.

D, I don't like the 45, its old technology, and have you priced a tb48?

(they must be made of gold?)

E, the FS5R30A is much more refined to drive as opposed to the FS5R50A.

Also yes, budget is one thing, having a family, house and the like is my main money outgoing, so I've made alot of the parts myself.

Mechanical, electrical, fabrication etc.

But just to add, just because it's budget doesn't mean it's dodgey junk!

Some of the bits may be Chinese, but the car is well put together.

(hasn't let me down yet!)

[nicksamaniac]

Also for info sake, this car weighs 2100kg wet. (scales at the rta/truck inspection)

The diesel/petrol 4.2l variants weigh closer to 2800.

And most heavy modded versions are well over 3000kg.

So it's not far behind a Stagea really.

[Tonba]

May I suggest something else.

Borg Warner EFR 7670 with Divided IWG T4 0.92 A/R turbine housing..

It will flow MUCH more then your 0.63 up top, while spooling faster. Will make the engine feel a lot more linear, not to mention the bearings/seals they use the CHRA are much, MUCH more suited to your application (off road).

Will need a new manifold, but you wont need wastegates, so you can save some money there, not to mention less moving parts and things too go wrong off road.

Can also have integrated wastegate which will improve response, and reduce plumbing, etc.

IMO - there is no other turbo out there more suited to your application.

Edited August 4, 2014 by Tonba

[Tonba]

There are so many people that prefer a setup 'that hits hard' rather then one that is linear in its delivery. This logic is beyond me... 9/10 on road, track and offroad smoother, more linear power delivery is not only faster, but is less likely to break things.

Edited August 4, 2014 by Tonba

[nicksamaniac]

That's a nice thought, but starting at $2200 its nearly half what my car is worth!

Was really thinking around the $1000-$1200 Mark. That's why I was considering the hyper-gear unit.

Also linear power delivery isn't really needed off road, even with the small setup I have now it doesn't even make boost in low range.

Even with my previous "whole lotta" 75hp it still climbed everything I pointed it at whilst just above idle.

Reduction is a beut thing!

Really the only time big power is requested is during highway speed, usually 80-120km/hr.

Overtaking slow stuff and uphills, the rest of the time is just to get the big bus off the line and keep up with traffic easy, without big revs everytime.

Hence why I'm after easy low-ish rpm boost but big enough to keep up at 5500-6000rpm. (if it's needed)

[Cowboy1600]

A hypergear ticks all the boxes, mate. A dirty 30 will put out a lot of gas, especially under high load. I reckon the .82 rear is the one you're after. IMO a .63 will choke a 3l.

[nicksamaniac]

Yeah after speaking with a forum member, who has been very insightful and extremely helpful.

I've decided to try a gt3037 with 0.82 ar rear.

I'm thinking this will still give good low end response with the newer design over my sh!!y little t04e,

And hopefully still flow ok up top.

Again Im not after outright hp, more just good drivability.

Thanks again for the info/feedback guys.

[Cowboy1600]

Save yourself a wad of cash, and possibly get better results and go the Hypergear. Stao has invested huge amounts of time and money building turbos suited to RBs. Couple that with an unending desire to improve his product and aftersales support which is second to none, and you'd be making a mistake to go a Garrett over a HG IMO.

Spend a couple hours here - http://www.skylinesaustralia.com/forums/topic/261613-hypergear-hiflow-service-continued/

[nicksamaniac]

Just to add another part to the whole equation?

Would going from the 0.63 to an 0.82 or 1.06 improve my very very poor economy?

After reading up further on engine ve and turbo back pressure causing a reduction in ve, this is another area I would love to improve on!

The 17/100 is just crap!

[XKLABA]

With low gearing and big wheels on a heavy car, 17lt per 100 isn't to bad

Playing with cam timing and more time tuning will help a little as well as driving style, but it will never get the mileage of a Prius

[nicksamaniac]

Soon as I've got a new turbo and tuned again I'll let yas know the results.

[discopotato03]

I'd basically forget about all the Skyline RB30 stuff because a Patrol (GQ ST ?) is a far cry from a Skyline in every possible way .

The Patrol is going to be heavier and geared to suit an RB30S carby job if the RB is OE .

In the interests of simplicity I'd have used the RB25 exhaust manifold and an IW gate turbine housing .

Ages ago Cubes had a GT3076R on a non VCT 25/30 and he said it started making positive pressure from 1500 revs . For a truck a GT3076R would be the largest I'd go on an RB30 because you want reasonable part throttle torque at low revs and torque from boost not too much higher in the rev range , particularly with a truck ratio gearbox .

I'd even look at the 52 trim version of the 3076R because you aren't after high rev high boost performance so anything you gain down low without any avoidable exhaust restriction would be a bonus .

If in your case you get positive pressure at 1500+ revs and strong torque from 2500 then it should work quite well . What happens after 6000 revs is irrelevant in a truck that isn't raced IMO .

A .

[nicksamaniac]

Sorry, but I have to disagree with some of what you've suggested.

I Can't use a low mount as they have major plumbing issues against the chassis rail due to how the motor sits between instead of on top of a crossmember.

With the gearing it has?

It does the same rpm vs km/hr as my rs4 Stagea with r32 GTR box in it.

These are both the same box. (internally)

The only difference is component size, drive shaft, axles etc.

The 4.9:1 diffs are only there to gear it back to standard with the larger wheels.

So they both do 2550rpm @ 100km/hr.

Its really not that heavy compared to the diesel versions. 2200kg approx.

Edited August 8, 2014 by nicksamaniac

[discopotato03]

Well IMO 4-500 kilos does make a difference , how would the Stag go if it was more like GTt weight ?

With wheels it isn't just matching gearing because their physical mass and revolving weight make a measurable difference . Your typical fourby wheels are ship anchors compared to decent road car ones and I hope yours aren't those chrome plated cast iron pieces of ship .

Anyway if you want the thing to feel reasonably sprightly you need torque down low and if it's from forced induction it needs to work in the ranges you drive it . I don't think for normal use a 3076R/3037 is small for 3 litres though that's not exactly healthy capacity for a 2.2 tonne car . Plenty of people reckon R33/34s should have had 30s standard and they are more like ~ 1400 Kg or 800 less than your Patrol .

Anyway I'd use a GT30 over a T04E and size the turbine housing around the rev range I used 90% of the time . If you can't low mount then non gated GT30 housings aren't hard to get .

Just remember if you get this wrong with turbo size and go too big you could end up with a 2.2 tonne R32 GTS4 .

A .

Edited August 10, 2014 by discopotato03

[XKLABA]

Um so is your car 2200kgs or is the diesel version 2200kgs?

[nicksamaniac]

Yes its 2100-2200kg, the 4.2l version are about 27-2800kg. Obviously its going to be slower then a skyline!

But its still quicker (a sh!t load quicker) then a stock patrol!

[nicksamaniac]

And for the record, no way would I run stupid chrome wheels on my 4by.

ITs 80% for bush use the other 20% is on the road to get to the bush!

[nicksamaniac]

35"x12.5" Bias-ply comp tires on 8"x 16" bead locked steel rims.

No chrome here pal!!!

And a pic of my current turbo.

[XKLABA]

Is that an LPG tank under back ? Is this on LPG ?

[nicksamaniac]

Yes it is an lpg tank (old pic), its not on gas anymore, was bought on gas planning on lpg turbo but was always chasing the tune.

So I decided to go back to fuel, then it just ended up with a twin cam head somehow!