NefMoto

just questions in general I cannot figure out

3rd gear WOT run, my boost target is 20 PSI, boost holds steady to about 4800 rpm, then its a steady decline down to 12 psi
kkk24 turbo on a 5 cylinder Volvo

after logging my turbo solenoid duty cycle goes through the roof trying to hold boost, so im assuming the ECU is doing its job properly

so far I have adjusted wastegate
replaced turbo solenoid
smoke tested entire system from MAF to intake manifold, and intake manifold
verified multiple times that the ECU is doing its job

is there any way to tell if my turbo is on the way out, I still have no shaft play, no odd noise, no oil leakage

I have tuned atleast 4 other Volvo's of my exact model with the same mods done, and they can hold perfect boost to redline
the only thing I have noticed when logging a comparable vehicle is that in general my duty cycle is higher to meet requested boost then others which would lead me to a boost leak, exhaust is a total straight pipe from the turbo

diverter valve leaking internally?

you know, I never really thought about that, I did leak test the vacuum/pressure side of it, but to remove it on my car means removing the turbo.... I have been thinking of upgrading to a forge one anyways, and that would probably pass my smoke testing also I have been doing

any tricks I could do to possibly tell? I do have access to OEM diagnostic tools/ memory logging now finally for this vehicle

What motor?

For reference, I have the stock K24 on my urS6 2.2L 5 cylinder... the compressor wheel is just capable of pushing 1 bar @ redline.  Just under 300hp.

If you are running this turbo on a Volvo 2.4 or 2.5, then you may have maxed out the compressor wheel.

think he is talking about the newer k24 found in volvo R models, capable of pushing  closer to 400hp out of the box, even ~450hp with the right compressor wheel, and not the REALLY old one found in audi s2 etc.  :)

Sounds very similar to issues with the diverter valve that I've seen before on the 5 pot S60R.

You can remove the valve from above, it's a &^&FF%$$ but it's possible.

Forge in the UK do a nice replacement.

If you change the valve and it's been broken be careful as adaptation will have maxed out the TCV duty cycle and it will overboost like mad, and on these blocks that's bad unless you have strengthened it.

I've had my expansion joints shimmed to avoid the block splitting as I've seen it so many times here in the UK.

The K24-7000 will not do 400hp on 98 RON, forget it. 350-360 hp is the limit for this turbo, when running locked wastegate.
Don't smoke test, instead pressure test. The problem could be occurring only at higher boost pressure, and your smoke machine probably works only at 5 psi.
Put 16-17 psi in there and see how it likes that.

Also make sure your cat is not loose or blocked.

again, this probably isnt the old k24-7000 or k24-7200 turbo, but the 15-20 years newer k24-7400, and yes it can reach 400bhp, even 450 with a drop-in billet-wheel..

thanks guys for the input, pressure test passed perfectly, we have a nice machine for this!, still does not mean the diverter valve is not leaking

i tried to remove it in the vehicle, its NOT happening, the bolts are frozen BAD, and it faces directly at the block so im forced to use shallow swivel allens... i plan on doing some porting to the manifold and such, and possibly upgrading the compressor wheel so i am probably going to go with a forge valve at the same time

the car has a 3 inch straight pipe with a straight through 3 inch muffler, i suppose i could hook up a backpressure gauge for kicks, its easy enough

i have heard of the sleeves cracking on these motors are upwords of 400+ hp, but it seems to be area specific, and even totally random as i have seen it happen to stock vehicles.

this turbo can probably handle 400hp with probably the worst EGT's you will ever see and who knows what the turbine RPM is, definitely way over what was ever meant for.

time to do some more testing and report back

I mistyped. Yes, I meant the K24-7400.
As to whether it can reach "400hp", no it can't. I've mapped a couple of these now, and there is no way you are reaching anything above 350-360, maybe 370 or so with super low compression ratio. The turbo does not flow enough and the hotside starts to choke you. I've ran them with locked wastegate as well.
Only way to do this would be race fuel or E85.
Billet wheel is not going to help you too much, because the turbine maxes.

How many K24-7400 turbo'd cars have you mapped?
The K24-7400 is smaller than the K24-7200 btw, and it can not hold the same boost to redline as a K24-7200 can. And people do not run around claiming 400+hp from a K24-7200 either, 370 is an accepted limit.

Boost profile K24-7400, 100% wgdc after 5500 rpm on Audi 2.2T motor:

5000 - 268kpa
5500 - 265kpa
6000 - 250kpa
6500 - 240kpa
7000 - 230kpa

Boost profile K24-7200, 100% wgdc after 5500 rpm on Audi 2.2T motor:
5000 - 283kpa
5500 - 280kpa
6000 - 273kpa
6500 - 268kpa
7000 - 255kpa

To reach 400 hp these engines need at least 1.65-1.7 bar to redline if using the standard (9.3:1) compression ratio.
At 8.5:1 CR they can make a bit more, but no way to hit 400hp on K24-7200 turbo, never mind on the smaller K24-7400.
Full boost on K24-7400 about 2900 rpm, Full boost on K24-7200 3500 rpm in 3rd.

well then maybe i am just outflowing the turbo, that was my thoughts originally until i tuned another almost identical car with the same modifications done, one even had a 3.5 inch downpipe to 3 inch straight, and that was able to hold 20 psi to redline with a pretty high duty cycle, but it still did it, other things i noticed was an all around lower % duty cycle then my car even when commanding 4-6 psi.

it never really came to light because not many people have the same car around here, or want a tune

ugh.. choke that turbo..  ::)
actually ive tuned none myself, but ive seen a few 2.5l 20v engines on the dyno around the 400hp mark over here in "the land of the volvos", mostly on 98ron or V-power (99ron) ;D

these turbos dont really like the boostlevels you are describing, and never operate that high in the volvo cars due to the increased engine volume + flow, the compressor flow is no doubt higher in lower PRs, and you wont max out the turbine below 400hp on 98ron.

if what youre saying were true for the cars in question, Volvo would have stuck with their MHI 16t/19t turbos, and not step it up a notch to these.. since the MHI turbos were really solid units which produced the widest of torque-bands.. :)

worth mentioning is that a stage 1 chip for these cars yield 354hp/493Nm.. on 95ron.
using 98 ron on top of that, combined with lowering backpressure from a better downpipe + exhaust and you are there.

I think there is a reasonable method of removing the valve,  if you can't find it give me a shout.

Yes the liners cracking can be random but I've seen a lot of tuned ones do it,  that said mine ran 1.5 bar with map issues for a while including a track day and all was well when the head was removed recently.

On swedespeed lol

I guess your Volvo engine must be magic then. A bigger turbo can't do 400hp on the Audi 2.2T, so by your logic the K24-7200 should do 420-430 on a Volvo.
Or what is a lot more probable, is that someone has a "magic dyno" ;)
The 0.3 liters displacement is not going to produce 15% more power on the same turbo out of thin air.

As for 20 psi to redline on this turbo on a 2.5 liter engine, something is wrong with the engine in that case, as it is not flowing.
The better an engine flows the lower the boost drops. I gave you figures from a completely bone stock Audi engine. With a properly ported cylinder head the k24-7400 can barely hold 1 bar to redline on the 2.2T, and that still does not make 400hp.

i really don't understand this forum sometimes, i was just asking for some help/tips/tricks because i was stumped as to why my car is different

the best numbers i have seen with an aggressive tune and higher octane fuel on these cars with a stock turbo i think was around 370-380, and that was one car, who knows what else was done

i'm not overly worried about the power its making, i cannot even feel the boost drop off, i just see it, and that was confirmed today after taking a ride in another s60r, this car had a downpipe with cat and 3 inch exhaust.....holds boost but is not any faster then my car

thanks for the help

Has your head had massive port work and/or larger valves installed?

no, shes all stock except the exhaust, intake and the tune

If your car is not any slower than the other car probably not much is wrong.
You can try to adjust the actuator a little. Chances are the spring inside has gotten tired (depending on the edge, they do let go a little).

Try unplugging the N75 and measure the base boost level on your car, then measure the base boost level on the other car.
Any difference?

argh, i got a FULL tank of crappy gas right now, need to get some octane booster and re-try some things, but from what i do notice between the two cars, mine spools a slight bit slower, and wastegate preload is about 4.5 psi, where mine is about 1 psi higher 5.5

Sorry, but your sentence makes no sense.

Which car has higher wastegate preload? Your or the other one?

yeah, i quickly typed as i am at work, my car has a higher wastegate preload at 5.5 psi, where the other one is 4.5

hmm, i never did check for this (http://www.vivaperformance.com/product_images/uploaded_images/k24-turbine-crack-1.jpg)

im going to pull off the downpipe and see how it looks on mine

aah, i was under the impression that the 7400 used the a/r .49 housing originally, but it seems thats not the case, they use the a/r .41, so you are quite right there.
(im sure atleast 2 of the guys ive spoken to said they have the .49 turbine housing fitted.)

true that 400hp is alot to squeese out of a .41 turbine housing on pump gas.. and yeah, there are lots of magic dynos around ;D



somewhat curious to weather you have tuned one of these prj, with a backpressure gauge, to see if it indeed was the turbine maxing out?
the data you posted seem to ride the choke-line of the compressor, and yeah, lowering the needed boost by 0.3bar could definitely yield 15 or even 30% higher flow if you are indeed choking it, just a thought.

sorry for hi-jacking the thread, just curious about the limits of this specific turbo..  :)

Backpressure gauge is not needed. I can tell you if there are backpressure issues off the top of my head on a 2.2T just by watching what timing it runs.
Maybe has something to do with the fact that I tuned more than 200 of them ...
The K24-7400 is a very well balanced turbo. The compressor maxes out just as the turbine does. Fitting a billet wheel on it, you will not see big gains, the original wheel is amazing for what it is.

No, definitely not. Have a look at the K24-7200 compressor map. The choke line is essentially a straight line until 2.6 PR, in fact the sweet spot is at 2.4 PR where it is most efficient.
Very similar to the K24-7400 I would imagine. 0.3 bar lower boost will give you less than 5% gain.

ok, was just a thought, you seem to know your 2.2ts  ;D

i know the original wheel is good, but there is now a billet wheel of 11 blade GTX design available for these that will spool quicker and give you ~35hp more to play with in mid/top end.
theres also a 6+6 blade wheel for even faste spool and more mid-end torque.

ever tried one of these? the difference with the 6+6 wheel was very noticable on a volvo S60r, i have no dyno numbers for it tho, just the same tune, different wheel, and seat of the pants feeling.

who knows, i think 35hp is a little bit steep of a claim, but still after seeing that i might get a forge CPV, and a billet 11 blade wheel, probably in the next 2-3 weeks so we will all find out!

i was thinking of saving up for a k24/k26 hybrid turbo, but im going to break something with that much more power, really not worth it for this car... lol

i dont know if it is.. but i know the turbo spooled 2-300rpms earlier and that the torque gains in mid-range were massive with the 6+6 wheel.
the 11 blade GTX design is supposed to spool like stock, but extend the powerband further up top, holding the boost till 7000rpm, let us know what you find  :)

parts on order, ill keep you posted sn00k, but im not holding my breath too much on a power gain, i have read reviews on these wheels, there is about a 5 hp gain and a wider power band, but as prj said in the past, this exhaust housing is restrictive, as is any small turbo, but for 5 hp atleast and the price, it cannot be beat.

Mine made 330BHP and 527NM on a conservative dyno.  3"DP, MTE Map, Water injection and Ferrita cat back.

parts installed, definite increase in power, and i actually dropped the boost 1 pound, went through it though, i had a slight exhaust manifold leak that was fixed in the process

new manifold gaskets, turbo to manifold gasket, billet 11 blade compressor wheel, turbosmart DV

its actually shockingly quick considering how safe my fueling is.

time to head down to the dyno, i would be happy if i got 300 awhp

seems stock tune with exhaust they can do anywhere from 250-270?