Jump to content
SAU Community

High Cr, Small Turbo Combination?

works 510

By works 510,
in Engines & Forced Induction

 Share

Recommended Posts

works 510 Experienced

works 510

Posted
Posted (edited)

Guys,

Im still accumilating info and parts for my conversion and had a interesting thought at work today.

If I remember correctly, the GMS Bathurst GTR's ran a 9. something to 1 Comp ratio on mild boost.

Now,

From what I read, the 30det isnt a fan of smaller turbo's that choke them down restricting power at decent rpm.

The Bathurst cars, being twin turbo, in theory, there would be no/minimal restriction?

While trying to keep costs down, I would like to keep my current turbo setup (kkk k26 2770 with 42mm ext wastgate)

Turbo is rated at 330ps.

Would the larger size of the ext gate help with back pressure and restrictions?

How would it go with using the 9.1:1 CR pistons?

I can imagine it would be reasonably smooth power curve if it could still make power up top?

Thanks for your time again

Edited by works 510
Link to comment
https://www.sau.com.au/forums/topic/279494-high-cr-small-turbo-combination/
Share on other sites
N1GTR Grand Master

N1GTR

Posted
Posted

Ok, this brings one guy to mind: "Al"

I drove his on a skidpan and quickly on the street, it was crazy quick, sure it doesnt have dyno winning figures but the way it makes usable power and torque it doesnt need huge power.

I can honestly say its the most fun GTST ive ever driven.

Hopefully he'll see this thread, if not, send him a pm - he's a really nice bloke :banana:

R31Nismoid Grand Master

R31Nismoid

Posted
Posted

Al's turbo isnt a 330hp/ps turbo steve lol... Its a fair whack larger than that

The problem you'll have Dan is the turbine housing. It'll choke up very easily.

You could have a small turbo, no problem there - but the key is to have a larger rear housing - obviously not too large :banana:

Gate size is largely dependant on boost levels... id imagine to make any power on that little huffer your going to be running a fair bit of boost.

This will mean you want a smaller gate rather than a larger one for optimal boost control as most of the exhaust will go via the turbine housing to get turbo spinning up to speeds for the boost you need.

Sydneykid Grand Master

Sydneykid

Posted
Posted

I don't think that compressor will have enough airflow to make meaningful boost at any decent rpm, after all 30 lbs per minute isn't whole lot. You can't just up the shaft speed as it physically won't handle it, plus it's just going to churn out hot air. Really it's too small a turbo for a decent 2 litre engine let alone a 3 litre.

Cheers

Gary

CEF11E Veteran

CEF11E

Posted
Posted

I had a 3071 based hiflow on my RB30det. it was built by sliding performance and made a shade over 250rwkw with boost tapering off after 4000. full boost was about 2400rpm and it hauled... no top and but for street use it was FANTASTIC!

never raced it but it was very fun to drive. it now has a dirty big holset hx35 strapped to the side of it and they are worlds apart. The hiflow I had used the stock rb25 housings and was really to small.

rob82 Mentor

rob82

Posted
Posted

I'm running 9:1 comp on my rb30/26 with std cams and twins-5's and seeing about 14deg timing at peak torque at 12Psi of boost on pump. So by the time I get 20 psi of boost into the thing I think my peak torque timing numbers will be around 8degrees which will be close to the edge on pump. However the gains in using higher octane fuel will be huge!

I think with bigish cams (270 and 10.5mm lift) you could get 10:1 comp in fairly safely. Remeber the bore/stroke ratio of the 30 doens't lend it self to high compression in comparison to the 26 and 25.

  • 2 weeks later...
psi Experienced

psi

Posted
Posted

Dan..

empty your inbox mate. I cant send you a detailed reply to your question if I cant send it to you!

Go and delete some old PM's out of ya box mate.. then send me another PM to let me know that I can send you the info your after!

cheers mate

Aaron

unique1 Mentor

unique1

Posted
Posted

i run a gt3076r on a stock internal 30 (refreshed) and its making boost at ~2000rpm and makes 1 bar (current boost setting) at 2800rpm, dont choke it too much it will just be a slug at anything over 4000rpm or so.

I put stock 26 twins back on the same motor and it was absolutely shocking and would struggle to rev out over 4500rpm, it was very very very bad to drive and was pretty much on boost just cruisin at 80kmh.

The 3076r is the smallest turbo i would personally use, there is no way anyone could say its too laggy.

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      Unpeeling the Orange

      By GTSBoy · Posted

      The rain is the best time to push to the edge of the grip limit. Water lubrication reduces the consumption of rubber without reducing the fun. I take pleasure in driving around the outside of numpties in Audis, WRXs, BRZs, etc, because they get all worried in the wet. They warm up faster than the engine oil does.
    • Dose Pipe Sutututu
      Unpeeling the Orange

      By Dose Pipe Sutututu · Posted

      When they're dead cold, and in the wet, they're not very fun. RE003 are alright, they do harden very quickly and turn into literally $50 Pace tyres.
    • GTSBoy
      Unpeeling the Orange

      By GTSBoy · Posted

      Yeah, I thought that Reedy's video was quite good because he compared old and new (as in, well used and quite new) AD09s, with what is generally considered to be the fast Yokohama in this category (ie, sporty road/track tyres) and a tyre that people might be able to use to extend the comparo out into the space of more expensive European tyres, being the Cup 2. No-one would ever agree that the Cup 2 is a poor tyre - many would suggest that it is close to the very top of the category. And, for them all to come out so close to each other, and for the cheaper tyre in the test to do so well against the others, in some cases being even faster, shows that (good, non-linglong) tyres are reaching a plateau in terms of how good they can get, and they're all sitting on that same plateau. Anyway, on the AD08R, AD09, RS4 that I've had on the car in recent years, I've never had a problem in the cold and wet. SA gets down to 0-10°C in winter. Not so often, but it was only 4°C when I got in the car this morning. Once the tyres are warm (ie, after about 2km), you can start to lay into them. I've never aquaplaned or suffered serious off-corner understeer or anything like that in the wet, that I would not have expected to happen with a more normal tyre. I had some RE003s, and they were shit in the dry, shit in the wet, shit everywhere. I would rate the RS4 and AD0x as being more trustworthy in the wet, once the rubber is warm. Bridgestone should be ashamed of the RE003.
    • Kinkstaah
      Unpeeling the Orange

      By Kinkstaah · Posted

      This is why I gave the disclaimer about how I drive in the wet which I feel is pretty important. I have heard people think RS4's are horrible in the rain, but I have this feeling they must be driving (or attempting to drive) anywhere close to the grip limit. I legitimately drive at the speed limit/below speed the limit 100% of the time in the rain. More than happy to just commute along at 50kmh behind a train of cars in 5th gear etc. I do agree with you with regards to the temp and the 'quality' of the tyre Dose. Most UHP tyres aren't even up to temperature on the road anyway, even when going mad initial D canyon carving. It would be interesting to see a not-up-to-temp UHP tyre compared against a mere... normal...HP tyre at these temperatures. I don't think you're (or me in this case) is actually picking up grip with an RS4/AD09 on the road relative to something like a RE003 because the RS4/AD09 is not up to temp and the RE003 is closer to it's optimal operating window.
    • Dose Pipe Sutututu
      RB20DE NEO smallbox clutch.

      By Dose Pipe Sutututu · Posted

      Either the bearing has been installed backwards OR the gearbox input shaft bearing is loosey goosey.   When in doubt, just put in a Samsonas in.
×
×
  • Create New...