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Author Topic: low boost issues high rpm, need some help  (Read 22899 times)
prj
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« Reply #15 on: May 14, 2013, 04:23:58 PM »

ugh.. choke that turbo..  Roll Eyes
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) Grin

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.. Smiley

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" Wink
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.
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krazydbiker
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« Reply #16 on: May 14, 2013, 05:31:25 PM »

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








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ddillenger
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« Reply #17 on: May 14, 2013, 05:37:04 PM »

Has your head had massive port work and/or larger valves installed?
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krazydbiker
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« Reply #18 on: May 14, 2013, 06:09:38 PM »

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

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prj
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« Reply #19 on: May 15, 2013, 12:34:31 AM »

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?
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krazydbiker
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« Reply #20 on: May 15, 2013, 10:50:02 AM »

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
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prj
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« Reply #21 on: May 15, 2013, 11:21:01 AM »

Sorry, but your sentence makes no sense.

Which car has higher wastegate preload? Your or the other one?
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krazydbiker
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« Reply #22 on: May 15, 2013, 01:10:34 PM »

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

im going to pull off the downpipe and see how it looks on mine
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sn00k
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« Reply #23 on: May 15, 2013, 02:13:44 PM »

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" Wink
The 0.3 liters displacement is not going to produce 15% more power on the same turbo out of thin air.

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 Grin



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..  Smiley
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prj
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« Reply #24 on: May 15, 2013, 02:45:54 PM »

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?
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.

Quote
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.
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.
« Last Edit: May 15, 2013, 02:47:29 PM by prj » Logged

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sn00k
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« Reply #25 on: May 16, 2013, 04:50:32 AM »

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  Grin

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.
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krazydbiker
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« Reply #26 on: May 16, 2013, 05:06:02 AM »

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
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sn00k
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« Reply #27 on: May 16, 2013, 05:19:31 AM »

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  Smiley
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krazydbiker
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« Reply #28 on: June 08, 2013, 07:13:48 PM »

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.
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dream3R
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« Reply #29 on: June 10, 2013, 10:50:35 AM »

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

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How to work out values from an A2L Smiley

http://nefariousmotorsports.com/forum/index.php?topic=5525.msg52371#msg52371


Starting Rev's http://nefariousmotorsports.com/forum/index.php?topic=5397.msg51169#msg51169

noobs read this before asking http://nefariousmotorsports.com/forum/index.php?topic=9014.0title=


ORGORIGINAL 05 5120 creator for Volvo
ORIGINAL Datalogger (Freeware) Author
ORGINAL finder of the 'extra' torque' limits
I don't have ME7.01 A2L I just use ID
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