> I like your idea of allowing changes to the boost control hardware in SP as
> long as the blower/turbocharger stays unmodified.
Thanks. A lot of hard thought has gone into this.
> Of course this would have a drastic effect on the SP classifications
> as they stand now, requiring a great deal of work to review the
> potential of all supercharged cars and reclassify them based on the
> new performance potential.
Actually, I don't think it's that bad:
1) Forced Induction cars are conservatively classed, in general.
2) Turbos/superchargers are fairly narrow-band devices, much like camshafts. As
the manufacturers build street cars, the turbos tend to be sized for street use,
not for all-out race use. As the street values throttle response over raw power,
and as "raw power" turbos have horrible throttle response (lag), most turbos
tend to be sized on the small side. While there are definately gains to be had
by running more boost through a stock turbo, they tend to be relatively small.
Nobody is going to slap on a boost controller and pick up 100HP.
3) Changes to turbos only affect the car under boost - which means "at full
throttle, fully spooled". The percentage of time on course when a turbo car is
at full boost is not large, and the bigger the turbo, the smaller that
percentage gets.
Given this, a potential problem child car needs to be already under-classed and
have an oversized turbo from the factory. I can think of only *one* car that
fits that description - the later-generation Supra Twin Turbo.
In any case, now is a fortuitous time to be considering this change, as the SP
classes are being overhauled anyway.
> I would respectfully suggest that you write a letter to the SEB and
> SPAC outlining this plan _and_ please offer to donate your time to
> help with the reclassifications.
I have done both. What happens (or doesn't happen) next is in the hands of the
SEB.
> The only potential problems I see with such a rule is that some
> stock turbos will allow competitors to create grenade motors
> (especially since they can't make any internal mods to the
> engine to help manage the extra boost)
There are undoubtably cars out there with weak links weaker than the airflow
available through the stock turbo. Allowing boost controllers lets these people
*save* motors, as they can now limit boost via the controller, where they can't
do that now.
However, I don't worry about people building grenades, as the "grenade line" on
a turbo car is very, very fine, and the rewards just aren't worth it.
At something like Indy or WC oval races, where huge chunks of time are spent at
full throttle and full boost per lap, and where there are many, many laps, the
small advantage from flirting with the grenade line - say 5HP - is amortized
over and over to the point of being worth it. But on a 45 second autocross
course, with a MUCH smaller full-throttle, full boost percentage, the risk just
doesn't pay off.
Besides, an SP turbo car can build a legal grenade right now - just run leaner
and use more ignition advance. I could do both right now to my
non-boost-controlled car, pick up maybe 5-10HP, and sweat bullets every time I
go full throttle. No thanks, not worth it, not even if I was made of money.
> Let us know if it comes up for consideration and I'll write a letter
> supporting it.
You may wish to do so. I'm NOT on the SEB, so I cannot speak for them, but I do
know the issue of turbo cars has come up this year. If you like this proposal
over other ideas like that "must use Stock exhaust+cat" proposal from the last
FastTrack, then you should make your opinion known.
DG
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