Turbo Bypass

Greg Hermann bearbvd at sni.net
Thu Aug 13 03:59:38 GMT 1998


High RPM low load might be able to do it, Part throttle, low RPM definitely
won"t. You'v got me tempted to run some numbers (another ten Excedrin
headache) to explore the situation, but I doubt it would happen. There were
an awful lot of draw through conversions built in the carburettor days, and
not even McInnes mentioned the possibility, and he was always pretty
careful and conservative.

On the surface, it appears to me that, simply because the air hits the
compressor before it hits the turbine, that it won't happen. It seems to me
that the best drive to load ratio happens at big loads--that's why you need
a wastegate. I can feel a late night coming on exploring this one
mathematically. Oh well.

I thought yeeoow was the whole idea. The thing I would watch is letting the
total tube, intercooler, and plenum volume grow past a couple of five
engine revolutions worth of displacement--otherwise a serious
yeeeeoooooww--whump (a synonym for "Hold the dash, we're gonna crash!")
might ensue when nothing changes for a bit after getting off of the loud
pedal!!

If this is a real problem--no problem. put a speed pick-up on the turbo,
and have the ecu open the waste gate a tad when disaster rears its head.
Autronics, for one has this capability. Never let fear of additional
technical complication retard your need for speed! To do so would get you
thrown off of the Seneca Lodge Racing Team! Yep, there's a story there.

The one that I have explored in more depth

                                        Greg


>In a message dated 8/12/98 8:47:45 PM Eastern Daylight Time, rublesck at ez-
>poa.com.br writes:
>
>> If you make the turbo run at vacuum, won't you risk over-speeding it and
>>  consequently damading it?
>
>yep.  Flashback: early 70's Accel marketed a kit that did it.  Overspeed at
>part throttle/high load conditions.  But wow! the thing would hit (fast) with
>big boost, when you stomped the pedal from a part throttle load.  The turbo
>would be spinning at a bazillion rpm, in high vauumm,  and then the butterlfy
>opens to feed it air..yeow!
>Mike V.





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