Of course it no way ideal to run very high intake air temps but thats why I would be interested in real world results and when are they really out if efficiency.

E85 is also really nice fuel as its basicly like running with race gas, so there no detonation problems even if IAT's would rise some as long as you make more power.

This.

Just because it looks like it can, doesn't mean it can in an efficient, reliable manner.

I understand that and its always a compromise when making more power and know when to stop when there is a bottle neck.

Just wanting for someone to post dyno sheets and / or IAT logs.

Best to remain n the conservative side of compressor maps as replacing an engine is considerably more spendy than upgrading turbos.

Let's not go to a "you will blow up your engine" discussion. Please remain posting only if you have dyno sheets, logs or real world results of what was asked about. Thank you!

Ok, thermal management is a function of compressor efficiency, so I do believe that is a relevant fact.

Also note that this is a thread from way back in 2015...

Datalog your N75 value and you will quickly see that the Stock K24 compressor wheel will start to falter at around 5500-5800 RPM's.. Let's say you target 1.25 bars of boost, at 5500 to 5600RPM's the boost pressure output will start to decrease. Typically you will end up with 1bar at 7K.. If you target 1.3 bars IAT will increase quicker and produce higher knock retard (on pump gas).
The stock K24 compressor wheel will not sustain 1.25 bars thru the entire RPM range.
The above data points will be difference between cars with cars with different exhaust systems.

Reviving this thread if someone finds this info usefull. The info Kevin posted was also our findings when trying to max out the stock K24's this summer. Got only around 1bar with the N75 maxed out, and after tighening the wastegate a turn the maximum sustainable boost at higher rpm is around 1.1 bar. So most likely the compressor is running out of breath or the compressor is being overspun which causes exhaust manifold back pressure. I measured the back pressure on my fabspeed exhaust with 200 cel HJS cats to see that its not restricting the flow too much. Theres around 0.3bar back pressure on the exhaust which is not ideal but not terrible. Definitely needs an exhaust upgrade with hybrid turbos.

I have GT2RS intercoolers and the IAT still seem to be at acceptable levels on 0-120mph pulls.

I hope to dyno the car next week and post results with pump fuel and E85.

Log:
https://cimg6.ibsrv.net/gimg/rennlis...cb3dc29c50.png

I'm making ~550rwhp on my k24's. Kevins 1 bar wastegates, 5 bar fpr, 997 GT2RS intercoolers, europipe exhaust, custom dyno tune, 91 octane.

I made 555hp to the wheels with my K24 car. Mine are not completely stock though, they are the FVD "Race" K24s which have slightly larger wheels on the exhaust side for more flow up top.

Relevant mods are 1.3 bar MAFless tune by Markski, 2.5" exhaust, 997.2 intercoolers, fender well intakes, 5 bar FPR.

https://live.staticflickr.com/65535/...2713a810_b.jpg

https://live.staticflickr.com/65535/...5f3c2822_b.jpg

Is that true about the exhaust wheels? I have a set of FVD race K24's that were converted with billet 18g inducer wheels. What would be the effect of the larger exhaust wheel?

That is a nice looking dyno, is it a result of the tuning or the modded k24s that got rid of that weird torque/hp dip that most 996tts seem to have after 5500 rpm?

Nice curve. What's your redline set at? Is there a reason you only ran it up to 6200 before letting up instead of going all the way to redline to see how the turbos perform on the top end. I would image your redline is 7000 or 7200 which is typical for most tunes so you are leaving closet to 1000 rpm on the table on that run. What dyno is that by the way?

You mean these ones? They have a bigger compressor and not turbine. Enlarging just the turbine doesnt make much sense as the turbine on the K24 is fairly large at a little over 52mm. (Garrett GT28 / Alpha28's are 47mm)

https://www.fvd.net/us-en/FVD123025A...t-send-in.html

OK that makes sense. They are K24 hybrids of some sort. The regular k24 won't flow 1.3 bar or will it?