Jump to content
SAU Community

Recommended Posts

So if I go by that graph the 3.2L has 300KW at the same RPM as my 2.6 (pretty close).

How is that even possible? I guess if it had a torque graph (why?) then it would have a massive increase.

But it is stopping at 7000rpm. Please tell me I am reading it wrong.

Edited by Stixbnr32

Turbo is too small. Turbine housing too small which restricts flow and chokes the engine. In this scenario you have no choice but to cut boost.

It will be interesting to see what an e85 tune does because if it makes no significant difference then the turbo selection is the problem.

Why would boost need to be cut?

I have a .82 housing on mine and boost holds flat to 8000rpm

Edited by sky30

Yeah the graph is slightly strange isnt it.

Well as long as it feels good I guess it is ok. I still think 7000rpm is low but if the turbo cannot flow it no point revving anymore.

At least its not spluttering and leaking water.

That is a success.

I would have thought boost would have carried on the whole way through and if there were lean patches from fuel/spark they would have suggested a fix with the amount of money spent on the engine.

Have they had their top tuner leave recently or something?

The limiter is set at 8000rpm. On the first tune @ 8500rpm .

The PT6262 CEA is rated over 700HP, some blokes say they get more, why would it stop at 600HP ?

When the Turbo was put on he changed to a larger back housing , size ?

So the Turbo should be good for at least 700HP ?

Could it be the spark ?

Put it this way my turbos are rated at 650hp and I am not pushing them with the same power you have and my boost is 22psi.

What size are your injectors? They can tell straight away if it is running lean and pull boost. Only reason I can think of to pull it.

But they should tell you and then recommend a fix. No point even going near E85. Go from 24psi to 18????

The injectors are ID1300

It is definitely not as rich as it was, but still a little soot comes out on start, pretty normal but nothing like it was since the build , it was heavy.

Going to have a AF sensor installed. The Haltech R34 Pro has , Wideband “auto tuning” using user definable target AFR table. Not sure if that is the same function as a sensor ,but the next builder will know

I think the boost could have been pulled because it was still farting when the boost remained higher. Just an uneducated guess ?

The car will be checked and sorted out before or during the next tune , I am not going back to Sydney to do it. Looking for a shop closer to finalize the work I want done.

Until then I will just drive it and have some fun :)

Yeah just drive it :)

Fair enough on the travel factor. I am not sure about that tune.

But I am sure the engine is super strong and you will have a lump of torque down low.

I still have all the response in the world when my RPM is high :) hahah.

The limiter is set at 8000rpm. On the first tune @ 8500rpm .

The PT6262 CEA is rated over 700HP, some blokes say they get more, why would it stop at 600HP ?

When the Turbo was put on he changed to a larger back housing , size ?

So the Turbo should be good for at least 700HP ?

Could it be the spark ?

If the engine flows too much air for the turbo, it will choke, limiting achievable power and rpm levels required.

Same way as a 2.5-3" exhaust is fine for a stock motor, but not one with a bigger turbo/motor.

PJ has got the rated number and more out of a few PTE turbos, 2l, 4cylinder, 40+psi.

Anyone care to work out the equivalent flow of a 3.2l, 6 cylinder at half the boost?

If the engine flows too much air for the turbo, it will choke, limiting achievable power and rpm levels required.

Same way as a 2.5-3" exhaust is fine for a stock motor, but not one with a bigger turbo/motor.

PJ has got the rated number and more out of a few PTE turbos, 2l, 4cylinder, 40+psi.

Anyone care to work out the equivalent flow of a 3.2l, 6 cylinder at half the boost?

That's good and fine to work it all out on compressor maps, but on a 3.2 you have a shit load more volume through the turbine. if the the rear AR is too small then you get back pressure prior to the turbine which not only slows down gas velocity but creates all sorts of issues with cylinder pressure and combustion events. That's why you have to cut boost.

In a 4 cylinder you can run big boost because you haven't got the volume of gas, so exhaust gas speed dosen't suffer and you can run a lot more boost (compessor) through the same turbo because the exhaust gas volume is a lot less, so no back pressure issues therefore high gas speed through the turbine.

In Pete's senario he wants response so who cares about top end power, its really all over by 7000rpm ish and that's where he wants it.

Good turbo for response from lower rpm, crap turbo from 5500ish rpm and up.

Edited by XGTRX

That's good and fine to work it all out on compressor maps, but on a 3.2 you have a shit load more volume through the turbine. if the the rear AR is too small then you get back pressure prior to the turbine which not only slows down gas velocity but creates all sorts of issue with cylinder pressure and combustion events. That's why you have to cut boost.

In a 4 cylinder you can run big boost because you haven't got the volume of gas, so exhaust gas speed dosen't suffer and you can run a lot more boost (compessor) through the same turbo because the exhaust gas volume is a lot less, so no back pressure issues therefore high gas speed through the turbine.

In Pete's senario he wants response so who cares about top end power, its really all over by 7000rpm ish and that's where he wants it.

Good turbo for response from lower rpm, crap turbo from 5500ish rpm and up.

I agree, which is why I can't work out why people still want/expect it to be making 700hp
  • Like 1

have to see it through pete!!

I just got to know..

I do not know how to stop, haha

I will do the mods to finish the build off, I do not like taking a chance with the work that has been done. Do the surge tank and pod cover, plus a AF sensor if needed. The idea of making sure I have 1/2 or 1/4 tank before playing would drive me nuts.

I was thinking of trying a bloke in Port Macquarie but do not know anything about the shop.

Everything will be checked out, I have spoken to a shop in Gosford about the work and the tune. He seems to have a good reputation and I can get there and back easily, saves time and money :)

6262 is rated at 730hp, if there are no restrictions on the motor it should acheive close to that figure.

Peter, what wastegate and boost controller you got?

HKS, EVC 6 boost controller

Showed Paul some pics and he said it is looks like the old HKS wastegate ?

Everything will be checked out, I have spoken to a shop in Gosford about the work and the tune. He seems to have a good reputation and I can get there and back easily, saves time and money :)

Whats wrong with the tune? I thought it was all sorted

Edited by XGTRX

That is alot of boost drop. Either they didn't tune in the controller properly or they are pulling boost for a reason.

Either is likely in this case I suspect.

Covering up an ignition issue, or lazy. Take your pick.

  • Like 1

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

    • Hey all just wanting some advice. I’ve just compression tested my RB25det and these are the following results  Cyl 1 - 135psi Cyl 2 - 135psi Cyl 3 - 120psi Cyl 4 - 140psi Cyl 5 - 130psi Cyl 6 - 125psi   do these numbers seem ok.  Thanks in advance 
    • I must say - this is how I picture all R31s!
    • Rust repairs completed, doors back on! pretty much totally back together running now. All future repairs will be fiddly wiring getting everything back up to road condition.  hasn’t  taken that long considering the condition I got the sub. note my helpers keeping the back seat warm 😂
    • SAU NSW Old Pac Cruise to Newcastle All Japan Day 2025 Sunday 27th July 2025 5:00AM Meeting Berowra Station Commuter Car Park 2 5:15AM Departure Cruise Via Old Pacific Hwy 7:45AM Arrival to Lambton Pool (Regroup) 8:00AM Arrival to Newcastle All Japan Day 2025 Meet Location: Berowra Station Commuter Car Park 2 Stop 1: Lambton Pool (Carpark) Final Destination: McDonald Jones Stadium for Newcastle All Japan Day 2025 Tickets: Newcastle All Japan Day 2025 $20 Per Car Spectators Free PURCHASE TICKETS HERE *Disclaimer* There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a CAMS permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU NSW and thus, treat others accordingly. • Any misbehavior will not be tolerated and you will be asked to leave.
    • SAU NSW Attends Machines & Macchiatos Cars and Coffee Sunday 13th July 2025 7:00AM Meeting Davidson Park 7:20AM Departure 7:45AM Arrival at Northern Beaches Christian School Meet Location: Davidson Park Final Destination: Northern Beaches Christian School Machines & Macchiatos Tickets: $10 Per Car $2 Spectators Pay at Gate LIMITED SPACES Register Below to Reserve your Spot. Members Receive Preference REGISTER HERE   *Disclaimer* There will be a lead and follow car so no one should get lost. If you would like to attend or bring others along please put your name down and a +1 as numbers will be needed prior! This is NOT a race and we will all be adhering to all road rules. If this is what you want please come to one of our many track days. This is an official SAU:NSW event and will be run under a CAMS permit. One of the things that really sets our club apart is our commitment to being true enthusiasts. When on normal roads we strive to maintain good relations with the authorities as well as the public in general. When attending one of Skylines Australia NSW events please try to: • Be aware of surrounding environment and act accordingly. • Drive courteously on the state’s roads as a true enthusiast should. • Understand how important it is to maintain the good name of SAU NSW and thus, treat others accordingly. • Any misbehavior will not be tolerated and you will be asked to leave.
×
×
  • Create New...