27Mm Ipra Restrictors

[r32gtrdrc]

Hi all,

I am looking for information on 27mm restrictors on the rb26dett...

ie:

a) A basic design to start with would be really helpfull( I can then get that machined up...and do further R&D from there on)

or

b)Purchase a set that have had the R&D already carried out on them.....

Any info/assistance would be greatly appreciated..

cheers

[XKLABA]

Hey Mate, when I was helping the BSM GTRs while it was in ipra we had some made up, try contacting JohnGTR

http://www.skylinesaustralia.com/forums/topic/414467-r32-gtr-getting-ready-for-wtac-tunehouse/

and see if he received the restrictors when he brought the car and if so if he is willing to part with them, other wise contact Jeff at Brandster Services and see if they still have them

[r32gtrdrc]

Onya!!!

ta... somewhere to start the process..

[Duncan]

+1, Jeff @ BSM, or Geoff at SSS are the guys who have had to use them.

you probably already know, but a gtr does not breathe very well through such a small straw.....you have a big task if you want to be competitive in IPRA with a GTR

[XKLABA]

And that is the truth of it, just like pushing poo up a hill

[r32gtrdrc]

Cheers Duncan..

Yes I am aware that I have a task and a half going forward...

After wasting my previous tarmac car and nearing completion on my new car, I am steering away from big trees and big concrete walls.... hence the mindset change into doing some circuit stuff.

I would like to play at a couple of different tracks and not just the one here in Perth, so IPRA seems like the direction..

I believe a new set 2860-7's would suit the agenda, running around 25--28 PSI on E85 ( and utilizing the previous Tarmac rally cars brakes/suspension etc) should get me "reasonably... competitive"..

Clearly, It will be a "Short Shifter Sally" type of set up... but any advice is graciously accepted..

cheers

[XKLABA]

-7s but get the .48 rear housing machined onto them, use standard cams, the BSM car was out of breath/boost by 5500rpm, so build the car to make as much boost as low in the rev range as possible to create torque, it can be done and I wish you the best, I was withe the BSM team from the start and help fabricate the car, right up till it went into sports sedans

[r32gtrdrc]

That's the plan...hence plenty of "short shifting"....My game plan indicates max torque around 3500rpm with the dash -7s and the .048 housing.

cheers

[2pee]

I understand the SSS one came via an airline with the flying rat on the tail.....seems like a lesson in self-flagellation is coming!

[warps]

I suggest you talk to a few IPRA guys about this. Even the 2L turbo boys are struggling to find drivelines to take the massive torque due to the limited revs. The 2.6 will exacerbate this even further - huge torque at low revs, and limited to the same power as the evorexes. You'll still have fun out there, but I don't think it will be at all competitive.

[hrd-hr30]

yeah, the BSM GTR had a huge appetite for front diffs. And they're not alot of fun to change...

It may sound weird, but you could make more power with a good NA 3.0 build than the restriced turbo motor will make, without any of the driveline drawbacks the turbo has.

Considered racingin AASA events instead of CAMS?

[djr81]

yeah, the BSM GTR had a huge appetite for front diffs. And they're not alot of fun to change...

It may sound weird, but you could make more power with a good NA 3.0 build than the restriced turbo motor will make, without any of the driveline drawbacks the turbo has.

Considered racingin AASA events instead of CAMS?

Chris is from WA. We dont do AASA racing in these here parts.

Think Im correct om saying the restrictors bolt straight to the turbo inlets?

[XKLABA]

I understand the SSS one came via an airline with the flying rat on the tail.....seems like a lesson in self-flagellation is coming!

yeah through BSM, Phil Coles ( drove the combined touring car ) son worked for the rat tailed liner company

yeah, the BSM GTR had a huge appetite for front diffs. And they're not alot of fun to change...

It may sound weird, but you could make more power with a good NA 3.0 build than the restriced turbo motor will make, without any of the driveline drawbacks the turbo has.

Considered racingin AASA events instead of CAMS?

the only time I remember change the front diffs was to change ratios, the original car ( which ended up as the CT car ) ripped the diff housing off the sump, and not that hard to pull out and put back, the hardest part was the pinion gear

IIRC the IP car made -/+ 300 rwkw, I'm yet to see a NA 30 come close to that in HP let alone torque, the box issues all but ended when they figured out what oil to run

Chris is from WA. We dont do AASA racing in these here parts.

Think Im correct om saying the restrictors bolt straight to the turbo inlets?

you are correct, IIRC the 27mm point has to be 50mm from the front edge of the turbo blades

[XKLABA]

I have always wondered how it would go if someone put 3-4mm sleeves in the bore and bring it down to 78-80mm bore reducing the amount of air the motor uses ?

and what effect it would have on the limited rev range

[hrd-hr30]

Maybe I'm getting confused with the 10 PPG dog boxes they used in a season then...

For the OP, BSM used something like 3.5:1 ratio diffs to try and get any speed out of the restricted GTR. I think BSM also used a taller 5th in the 0.7something range, and top speed was still a problem for them.

You'd really be up against it these days with the emergence of the fast V8s since the BSM GTR was around.

Edited November 26, 2013 by hrd-hr30

[XKLABA]

Yeah they did quite a few boxes, the diffs where a custom 3.9 to take advantage of the massive torque the car made, they used std 5th for the 1st few then went the longest PPG offered I believe

[hrd-hr30]

Jeez, I was starting to really worry about my memory, so I did a quick search on the IPRA forums...

Lofty said the GTR had 3.5 diffs and 0.75 5th and it still wasn't enough even for EC.

He also said they "couldn't stop the front diffs exploding" when they tried a "solid transfer case and locked rear diff". Apparently alot faster but too fragile.

Custom gearing obviously required to try and get some sort of top speed out of the severely limited rev range of the restricted engine. Which is why they never bothered running it at PI or Bathurst.

Edited November 26, 2013 by hrd-hr30

[XKLABA]

ok, the transfer case mod was done just before I stopped helping, and at that time it was still 3.9, so unless they put 3.5 after I left I wouldn't know, I had to much of my own shit to take care of to keep up what was going on with them, but I'll be talking to Jeff next week so I'll ask him

I know at the time they had a mod done to the back of the box so they could "dial in" preload on the transfer case and that was chewing out front CVs at slow speeds and made it interesting to turn around the parking lot unless backed off