924Board.org

[u63af]

Hi guys I am looking to change my old 924 turbo s2 into a race car for competing in a classic race series. My intention was to go to electronic injection but I have now found out I have to keep mechanical injection.

Car already has front mount intercooler fitted. Was going to go with custom turbo and 4 branch manifold, tial 38mm dual port wastegate, get head gas flowed, flywheel lightened, crank knife edged and balanced, 3 inch exhaust.

What else should I do to get more power, it needs to be at lease 270 bhp to be competitive? Any mods to fueling system or ignition system?

[ideola]

With the S2 ignition, you won't be able to much because you need the DITC to work correctly. But you could definitely go with a more powerful coil to get stronger, cleaner spark, and you might consider a good high quality lead wire like the Kingsborne wires we provide.

You can get about a .3 bump in compression ratio by reducing your head gasket thickness to .26" using the Cometic MLS gaskets we provide. These would be a good idea regardless of thickness if you're planning to run higher than stock boost. I would also recommend installing the ARP head studs. And since we're talking about the head, the biggest constraint on these cars is the head. If you're allowed to do mods to the head, you should definitely consider a big valve head, as well as a more aggressive cam (Integral Cams seems to be a favorite around here).

You didn't mention it, but I presume you have or intend to have a boost controller of some sort? If you go with a more efficient turbo, I would think you'll have no trouble approaching 300 BHP by upping the boost, provided that you are able to provide appropriate thermal management (intercooler).

As for the fueling system, there is no empirical evidence regarding the upper limits of the CIS system. But one thing I would strongly recommend is to have your injectors cleaned and flow-balanced (I used http://www.jaguarfuelinjectorservice.com/ ) and also have your fuel distributor rebuilt and balanced (try http://www.jaytanindustriesinc.com/index.aspx or http://www.specialtauto.com/ ). You don't want to be leaning out under high boost due to a bad injector or a clogged port on the fuel distributor.

Once you have those items benchmarked, you could then consider the UTCIS-PT digital WUR or the Brian Leask adjustable WUR. Both of these options would provide additional fueling at high boost, although I don't know if this would violate the rules for keeping stock CIS. If neither of those is permissible, then you may be stuck with shimming the primary pressure regulator. You could also look into rigging up the cold start valve (and maybe adding a couple of additional ones) to provide extra fueling at boost. But I would wait to do that until you knew for certain based on dyno testing that add'l fueling was required beyond what you can do with CIS.

Can you add a water-methanol injection system? This could provide additional charge cooling and an octane boost.

If you already have a FMIC, you can add water sprayers to it to improve its efficiency.

The other obvious things to mention are that shedding weight and improving suspension will make the car faster regardless of BHP.

Good luck, I hope you'll post often about your build!
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erstwhile owner of just about every 924 variant ever made

[Rasta Monsta]

FWIW, I have recently heard rumors that Integral is shuttering.


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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[ic932]

You could do a bit of research on the 924GTS model. IIRC it was rated at 270bhp in Clubsport spec.

It used a 928 fuel distributer in conjunction with an expensive mechanical fuel injection pump which is probably "out of reach". But you might be able to play with the 928 fuel distributer in some way for extra fuelling? I can't remember offhand how much boost they were running?

[morghen]

[Shurick]

GTS Club Sport where running @ 1.1 bar of pressure.
They utilized 928 fuel distributor to provide enough fuel. However they used only four injectors, don't know where are they taken from.
AFAIK, the fuel pump was electrical. Only GTR and GTP where using Kuegelficher mecanical pump/injection.
_________________
WBR, Shurick
'79 931 -- intercooled K26-3060-6.10 turbo @ 1.2 bar, EFI+EDIS, 951S brakes, stripped interior, 951 look.
'86 924S -- R.I.P.
https://www.instagram.com/ru_pacecar/

[Shurick]

_________________
WBR, Shurick
'79 931 -- intercooled K26-3060-6.10 turbo @ 1.2 bar, EFI+EDIS, 951S brakes, stripped interior, 951 look.
'86 924S -- R.I.P.
https://www.instagram.com/ru_pacecar/