Building a Racer to beat a Honda CRX - Options?

[Cory_Langford at bcit.ca (Cory Langford)]

Well, the 1.7 has to be almost stock.  I can port match the head to the
exhaust gasket size, but not port the internals, or change the valves, etc.
It is pretty much what most tracks run a production class.  Very limited
work allowed on engine and trany.  Unlimited on brakes, suspension, etc.

So swapping the head is a no go, and putting in a full 1.8 to match the
better head bumps it into the very bottom of the next class.

I guess the next question is, does the old 1.6 flow better?

I have to look into carb restrictions.  I know you can't add dual carbs if
it only came with one, but I am not sure if you can change the carb or
rejet it etc.  Never thought carbs until I just started thinking about the
old 1.6L.  Did they not have a carb'd model?

There is a new class for up to 1500cc with carbs only.  Seems like the 90HP
civic hatchbacks are hitting that one.

The tranny I have to use the stock gear ratio, but I can change the final
drive and add any kind of dif I want.  So quaife would be a requirement to
get all the power to the ground out of the corners I would suspect.  And I
did bump into a 4.5 (I think it was) final drive set from eurosport (I
think it was)

I know the 1.7's top out really low on the RPM, so I was wondering if going
the other way on the final drive might help.  With the long gears, use the
smallest final drive I can find to keep the lower revs (2500-3500) into the
max. speed possible rather than constantly running it up in the 5000 range
where there doesn't seem to be any real power on those little beasts.

I am tracking down some of the Rabbit guys locally, but I have not seem to
many of them in this class. There is a rabbit specialty class with a little
more open mods allowed but only rabbits of course.  I might just have to
get an old rabbit shell.  Just wanted to try it with a roc as it has some
sentimental value :)

Cory Langford


"Dan Bubb" <jdbubb@verizon.net> wrote on 23/01/2007 01:02:22 PM:

> Don't know what legal mods are, but the 1.7 might have a problem in
> this class.
> It's got the early head with 34mm intake valves, so there is no way
> it'll match the valve area of the Honda. Being able to swap to a
> later GTI head would help a lot.
> Camshaft is probably pretty mild also, although I know of no way to
> directly compare it to the Honda. All I can say is the torque peak
> on the VW is around 3000 RPM indicating generally restricted
> breathing either from a mild cam or insufficient valve area.
> You'd have 13% more displacement, so you should be able to match the
> Honda's peak torque rating despite the poorer breathing, but I can't
> see any way you'll match the Honda's peak power.
> And despite some of those catchy phrases about torque does this and
> HP does that, I think the HP deficit will kill you.
> You might be able to make up the power deficit with a close ratio
> tranny, but again, don't know if it's legal to swap trannies and the
> 1.7 only came with relatively wider ratio boxes.
> Is anybody else running a VW in this class that could give you some
> indication of its competitiveness?
> Dan
>