3GENJDM: New findings on 2.0 ct20b GenIII w/mods

[KU_MechE]

Originally Posted by Emily Hux

The turbine wheel will go out at any boost level if you have engine internals or media from powder coating a valve cover coming through it. Haven't experienced a ct20b just going out at normal levels (16-22psi).

By media, you mean powdercoating flaking off or the blast media not properly cleaned out from the baffles?

Any progress on this project? What is your solution to holding boost on a CT20b?

[doom26464]

Originally Posted by Emily Hux

We did modify the factory wg and put the factory intercooler back on. The ct20b at 24psi was just surging going on boost down track and noted on dyno. Apparently the ct2ob needs the back pressure of the factory intercooler, since alot of the surging was corrected when we did this. The car reacted perfectly just setting the boost at 22-23psi. Still have the problem of spinning in the 60', so we installed a line lock through the cruise control paddle on the steering wheel. I do have our custom coilovers on the rear so she should properly squat and use the 255 radials. Just waiting to be able to drive again.

this makes no sense. saying the factory intercooler is better is ludacris. If you where having surging issues why not run dual bov

[klue]

Originally Posted by doom26464

this makes no sense. saying the factory intercooler is better is ludacris. If you where having surging issues why not run dual bov

Its more likely you dont understand the principals at work.

[doom26464]

Originally Posted by klue

Its more likely you dont understand the principals at work.

im guessing its the housing of the turbo causing surge issues. Still running the factory cooler at thoses levels just seems bonkers to me

[CJMR2T]

Something with the whole IC and correcting surge makes no sense...

Surge is simply the reversal of flow within the system.. It is cause by the turbo flowing air too much air for the engine size and boost pressure...

Adding a more restrictive IC (i.e., stock) thus further reducing what the system can flow would worsen surge, not make it go away.

I agree fully with doom26464 and I full understand the pricipals at work (been designing and building turbo system for 15+ years) and just explained the basics of them...

Again, surge is simple a point where the system can not flow what the turbo is tring to force thus causing a reversion in flow and causing compressor stall (or better said, Cavitation)...

[CJMR2T]

Actually after a bit more though, the IC could have an effect on the turbo hitting surge points...

Its not the turbo that needs the "back pressure" of the IC to stop it from hitting any surge points cause as I said above, this would actually make it more likely to surge.

Its the Engine itself and the combination of Turbo size (well turbine size more correctly), IC flow capability..... With the stock IC, the flow limit (more so "pressure drop") is limiting the power produced at any point in the RPM range. This also happens to limit the exhaust energy availible to drive the turbine.. This is obviously going to effect the boost rise (making it slower) thus keeping the turbo from hitting any surge points.... A full datalog of both IC setups would show this.

I'd venture to say though that It would be better to run the better IC and lower the boost or better yet, run a boost controller setup that controls boost by RPM and gear. This would allow you to still run the same boost with the better IC but slightly decrease the rise rate keeping the compressor from surging...

[mattdouken]

What has the world come too, when people in the mr2 world start to question Hux racing....? Thats ludicrous..

[SW20jiro]

Bunch of Turbo nuts says I! Very interesting information however. Wish there were more! Did the motor finally blow up???

I hate when a good TV series suddenly stops showing.....

[SW20jiro]

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some good reading!