Power Upgrade

[William Hindmarch]

Hi

I am upgrading my Supersport R from 180 bhp to 220 bhp with throttle bodies, etc.  It is a series 3.  Will i need a bonnet cutout for airflow into the engine?  Essential or optional?  thanks

[OliverSedlacek]

I've seen a 236 bhp K series run without the cutout and with no sign of overheating. I don't know the spec of the rad though.

[nickh7]

I thought the cut out was to let the throttle bodies take in more air

[Gregs79]

I've been considering this as well! Look forward to the responses.

[William Hindmarch]

Yes it is for airflow and the more cold air into the engine the better. I am not sure though whether the piper cross filter will fit without a hole cut?

[Grubbster]

I'd say it's optional. My 230bhp K is on throttle bodies with a pipercross filter under the bonnet with no cutout, so it isn't essential. 

[LawrenceR]

AFAIK on a duratec it is a requirement. I have a SSR on order with the 220 upgrade and am having the cut out.

[oldbutnotslow]

I would agree with Grubster. However its a reasonably straightforward job to make a cut out providing that you have an air nibbler. These are a couple of pictures of a former 1.4k that I converted to a Duratec but with the short bell housing which brings the engine further toward the centre of the car.

I managed to borrow an R500D bonnet which I used as a template. Using 2 layers of heavy wallpaper lining paper stuck together with wall paper paste which were taped to the bonnet whilst still damp and allowed to set I was then able to make a cutout in the paper that was a "good fit". The template was then transferred to the freshly painted bonnet and the hole cut with the air nibbler and finished off with edging strip.

I HAVE PICTURES BUT CAN SEE HOW TO UPLOAD THEM AT THE MOMENT 

[Mark Durrant]

OBNS

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[John Vine]

I guess it depends on what TBs you're fitting.  If you're going for CC's rollerbarrels, you'll need the cut-out on a Duratec S3 (the SV doesn't need it). And it's not just for airflow -- the air filter won't fit without the cut-out.  On a K, bear in mind that the motor is tilted to the exhaust side, which gives enough room on the opposite side for the RBs to fit snugly under the bonnet.

 

JV

[AdamQ]

I have a Duratec in an S3 with Jenvey TBs and no cut-out.  Initially it had the Pipercross foam filter on it but it now has an alternative arrangement (still with no cut-out) whereby the air enters behind the number plate on the nose cone, goes through an in-line filter and then on up to an airbox.

FWIW ...

Adam

[7 wonders of the world]

If your using Jenveys then look to use one of Bernards (Scouse) airbox, these fit without a cutout and fresh air from in fornt of the rad can be ducted to it, makes sod all difference on the dyno to something like 2BHP when I did back to back power runs.

 

[OliverSedlacek]

YMMV. We got a 16BHP drop with the Bernards Scouse airbox.

[William Hindmarch]

Thanks everyone for all the input, much appreciated!  I am speaking with CC (their roller barrels are being fitted) today as well to see what is their preferred route.

[johnv]

I have RBTB's and a BC airbox 210 with no cut outs (also pipercross filter fits fine)