Aerochargers etc: real back pressure numbers

[Kris Weldy]

Very good data-im looking forward to putting together some like data on my
supra-great post!Your freind,
Kris Weldy
Arlington Texas
Jap spec powered Supra
Mini hennessey Viper(dodge avenger * bling * bling).
----- Original Message -----
From: "Frank F Parker" <fparker at umich.edu>
To: <diy_efi at diy-efi.org>
Sent: Monday, October 15, 2001 7:05 PM
Subject: Re: Aerochargers etc: real back pressure numbers


> > > Twice the exhaust BP than boost pressure ? So you're saying your
exhaust has
> > > 30 PSI backpressure ?
> > >From reading "Maximum Boost" by Corky Bell, this sounds plausible.  I
> > believe at one point he says that "after the crossover point, when boost
> > pressure surpasses exhaust backpressure, you can start to make serious
>
> Corky told me typically 2/1 or worse especially on some factory systems
> where they use tight hsns to prevent that horrible "turbo lag".
> I asked some other known experts at SEMA a couple years ago and got
> similar answers.
> Being curious and since I was allready using a 12 channel datalogger and
> wb NTK to tune the Typhoon I had just purchased with its new Garrett
> TE-60 turbo, I instrumented the TY with pressure sensors and EGT probes
> to measure back pressure before the turbo and manifold (boost) pressure
> as well as egt before and after the turbo.
>
> Was talking to Harry at PTE at the time about getting a SppedPro for the
> TY and another project with a Northstar, and he offered a new "hi-perf"
> turbine housing for test that he had developed for the GN world and which
> had shown on the track to be worth about 0.3 in the quarter. He suspected
> it would show lower turbine back pressure and boy, did it. Results below:
>
> Old TE-60 ( stock 0.63 hsn ) ,  0-90 mph run
>
> turbine inlet pressure: 23.8 psi
> manifold pressure: 16.0 psi
> Ratio: 1.48   much better than previous experts
> would have led me to expect but
> the TE-60 is a very hi-po turbo.
>
> TE-60 with PTE 0.63 high perf turbine hsn,   similar run
>
> turbine inlet pressure: 16.5 psi
> manifold pressure: 15.2 psi
> Ratio: 1.09 Vastly improved and before u ask,
> it did result in improved accel
> especially at high end.
>
> EGT at 1/2 shift: 1500 deg inlet,  966 deg out
> EGT at approx 90: 1538 deg inlet,  1088 deg out
> A/F as measured by datalogged NTK box: 12.4 a/f (kinda lean)
>
> Temps out turbo (before IC): 126 deg start, 197 deg end run
> Temp into motor ( mostly stock water/air IC ): 120 deg F
>
>
> 2nd run with PTE hsn:
>
> top 2nd: 1531 deg in, 994 deg out
> 4th gear 1573 deg in, 1130 deg out
>
> This run the a/f was a little leaner at 12.6 and raised the EGT's at both
> sides by 30-40 deg.
>
> All pressure sensors were quality SenSym units and temp compensated.
> Thermocouples were type K and calibrated with an Omega cal unit.
>
> Hope this is of interest to those like me who read about what things
> are supposed to be ans what they ended up being in this one instance.
> As they say, your results may vary.
>
> Frank Parker
>
> 92 Ty
> 89 S-10 V8
> 65 Corvair/Northstar
> 2000 STS
> C5R crew/engineer
>
>
>
>
>
>
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