How do you read a compressor map?

[gasketmaster]

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Originally posted by glhsken Terry, that 50 hp would put him in the 74% island barely... but spinning hard.

They put that top line across the map for a reason:big grin:

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There is a lot to do with set-up.. I've seen a car with the same turbo make 340+ hp on 25 psi of bost.

Of course!

[4sfed4]

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Originally posted by gasketmaster They put that top line across the map for a reason:big grin:

I like to work under the assumption that the maps are say....oh......50% conservative!

On a serious note, when I asked Turbonetics point blank, they confessed that the maps are roughly 8-10% conservative. So, if what they ay is true, there is a little more breathing room than we think just looking at the maps at face value.

[gasketmaster]

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Originally posted by 4sfed4 Ok......well that means that you are nowhere near the absolute flow limits of that comp wheel. I might try to milk what youve got for a bit :big grin:

While this may be true I have seen many examples where the car made no gains in ET or mph after a certain amount of boost.The turbo was able to raise the boost pressure but no gains were made.In our testing this was normally occuring about 2-3 psi before the turbo would make no more pressure.
Yes........it would hold steady for the entire run.......just wouldn't deliver any more MPH.

All of my experience is in drag racing at very high boost........I really never evaluate these turbos for their street manners or anything else.
We put one on.........run it to the boost limit one pound of boost at a time.........then we put on a different one and run it to it's limit...............and so on :big grin:

Intercooler inlet air temps and backpressure readings will help guide you along the way.

The maps will get you close but......sometimes you just gotta try some things and see what works and what doesn't

[BadFastGTC]

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Originally posted by fkatzenb Here is a guestimation for a general (no disquishing between swirl or g) unmoddified 8 valve. RPM 6,000 5,000 4,000 3,000 2,500 VE 77% 83% 87% 89% 88% you can expect a 3% increase with a good porting in the 2500 to 3000rpms and a 1-2% on the other rpms. frank

Frank,
Where did you come up with these figures?

[glhsken]

Quote:

Originally posted by gasketmaster They put that top line across the map for a reason:big grin:

Pat C and I showed you could go well past that "line" with the stock turbo's... Not saying it's the best thing.. but for streetability and strip.. its a vialble option. I ran 2.4 bar (20psi) and made 270 whp with the stock 50trim t3.

[91DSX]

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Originally posted by glhsken Pat C and I showed you could go well past that "line" with the stock turbo's... Not saying it's the best thing.. but for streetability and strip.. its a vialble option. I ran 2.4 bar (20psi) and made 270 whp with the stock 50trim t3.

Was this on a ported head? I've been looking at the compressor maps a lot lately (great thread BTW) and figured that at 20-22psi I should be in the 360FHP and very close to 300WHP range with a T04E regular 50 trim and a .63 Stage II turbine (RP Stage II), but what happens if I decide to run a tad more boost. . .

BTW Does anybody have a lot of street experience with the aforementioned turbo?

[glhsken]

No... stock head back-cut 3 angle.

I made 290 whp at 22psi with the E 50 trim (exact same RP unit you have)... Car was not tuned well. From my ph conversation with Bryan, I would have been well served to drop 5 psi (minimum) base fuel pressure (should have cracked 300 whp then easily... BTW, that was on 93 pump gas.

I really like it for the street. Much more progressive power. Hard to explain, but it feels slower but runs faster...

[91DSX]

Hey this is on a 2.2 right, should I recieve less lag with that turbo on my 2.5 because of the turbine size? Its great to hear that was on pump gas, makes it so relatable to me!

P.s Thanks for answering my goofy questions!

[contraption22]

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Originally posted by 91DSX a T04E regular 50 trim and a .63 Stage II turbine (RP Stage II), but what happens if I decide to run a tad more boost. . . BTW Does anybody have a lot of street experience with the aforementioned turbo?

.5 speed will be better, 2.5liter will be better. Its laggy with a 2.2 and an automatic in a street car. Im still working on tuning issues, and its improving.

[glhsken]

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Originally posted by 91DSX Hey this is on a 2.2 right, should I recieve less lag with that turbo on my 2.5 because of the turbine size? Its great to hear that was on pump gas, makes it so relatable to me! P.s Thanks for answering my goofy questions!

LOL... but of course... A 2.2L. So you know what to expect... My car way too little timing way too much gas... spooled slowly to 10 psi at 4k.... then ramped quickly to the cal set 22psi.. Full boost by 44-4500 rpm.

Bryan was able to get his set-up to spool even quicker by reducing the fuel.. I think based on mph chart he was at roughly 36-3800 rpm when it would hit hard.

Yes.. A 2.5 will spool quicker, but also runs outta steam by 5k rpm or so... I work regularly with a 2.5L car with the stage III turbine wheel (350/390 on the dyno 25 psi).

[glhsken]

ALSO!!! I wouldn't recommend anyone look to try for those #'s on pump gas unless they pay attention to detail on the set-up. (how's that Terry?? )

[turbovanman]

Quote:

Originally posted by glhsken Pat C and I showed you could go well past that "line" with the stock turbo's... Not saying it's the best thing.. but for streetability and strip.. its a vialble option. I ran 2.4 bar (20psi) and made 270 whp with the stock 50trim t3.

Is that a hybrid turbo or the T3 off the R/T's. I am running the stock turbo off one and can muster max 26 psi of boost-does that sound right-thats with the wastegate locked with vacuum so it doesn't open under full boost?:big grin:

[glhsken]

T3 was referring to what we call a stock TII turbo... t3 series 50 trim... Different cars act differently... Pat and I both maxxed out at mid 12.8's and 109-110 mph with stock turbo's. Pat went 1 step further and added a big cooler.. 12.4x and 111 mph.

My car would hit 20 and slowly fade to 18 over the length of the track.. maxxed out.

[gasketmaster]

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Originally posted by glhsken ALSO!!! I wouldn't recommend anyone look to try for those #'s on pump gas unless they pay attention to detail on the set-up. (how's that Terry?? )

OK..........THAT'S IT!!!!!!! Ken is picking on me again..............MOM!!!!!!!!

[Vanquizor]

I noticed it mentioned several times that some are tuning by backpressure readings, I was just curious as to exactly where/how you were taking these readings. I've also heard a general rule of thumb that 2:1 backpressure vs boost is a good target for a street car// any thoughts?

Finally on compressor maps I was playing with the utility on Ray Hall Tourbocharging's site, (http://www.turbofast.com.au/turbomap.html ) anyone use this tool/want to speak to it's accuracy?

thanks!