Duratec Roller Barrel Conversion Numbers

[juleslid]

I got the official roller barrel conversion done to my 175 Roadsport SV by CatMids in the summer, and loved the feel of the engine, but have only just got round to testing the results on the rolling road.

So, for the fact fans out there, here are the numbers if you're thinking of getting the job done yourself:

 

First rolling road session, after enthusiastic running-in ("Motoman" style), decatting and fitting more sporty silencer;

182 bhp at 7100 rpm

141 lb ft at 4000 rpm.

 

This morning, with the roller barrels;

199 bhp at 7600 rpm

149 lb ft at 5900 rpm.

 

Being an SV I've gone for the subtle approach with the air filter completely inside the bonnet. Unfortunately, this means that it is jammed up pretty close to the inside of the bonnet, especially at the front, and I was worried this created a low pressure area, so to test this tried one more run with the bonnet off;

205 bhp at 7600

153 lb ft at 5800. Bingo!

 

So, now to the question for the forum:

Any good ideas out there for allowing air through the side of the bonnet?

Drilling holes is the easiest, but wouldn't satisfy my aesthetic values!

And I don't want to have all the gubbins sticking out of the side that you see on S3's with throttle bodies.

Any thoughts?

Jules

 

 

 

[Jonathan Kay]

Mmmm.... facts!

 

Could you post a top-down view of how everything fits at the moment?

 

Did you read that discussion of ducting air through the hole in the nose?

 

Jonathan

 

Edited by - Jonathan Kay on 3 Dec 2013 10:01:45

[Guest]

Is that just the throttle bodies then or was more work done?

 

how much is the conversion if you don't mind me asking?

[MartinH]

How is the driveability Jules? I have a very similar setup althouth Cosworth single unit roller barrels instead of the Caterham ones. Same dimensions, trumpets, TPS, and air filter though. I have a bit of a kangaroo thing going one which I ignored to start with but its annoying me now. I am thinking about having the cams upgraded over the winter now as well and then possibly a mapping session if the kangaroo is still living under the bonnet!

 

 

[juleslid]

Ta for the replies.

Jon, not sure how likely I am to work out how to include a picture, but imagine a foam air filter close up to the left front side of the bonnet, probably touching at the front. Read that discussion, but would be happy with a simple hole (with a grille or something), or some sort of neat air intake, but probably not a NACA duct as that would have to go inwards towards the filter.

Tom, it was just the standard roller barrel upgrade, still got the standard cams, valve springs, etc.

Think it was about £2400, gulp!

Martin, the driveability is actually better now. With the old plenum chamber I was always cautious when putting the power back on as the kangaroo was never far away. The throttle bodies seem much better, possibly helped by having a stronger return spring to work against.

[Pete - W.Sussex]

Would one of these do?

 

here

[juleslid]

Pete, nice Lufteinlass!

I had in my mind a simple sort of grille arrangement, or maybe some louvres like on top of the bonnet.

But that very carbon intake you suggested does look rather good.

Probably a bit rich for me though...

Cheers, Jules

[MartinH]

The Sigma Supersport has a thing like this now. Someone will probably have a better picture but I found this on the web. here its is like a little grille with air filter material over it I think.

[MartinH]

Or This C400 race intake from CC.

[John Vine]

Thanks for the info -- most interesting. When you've done a few miles, could you post up some info on the effect of the RBs on fuel consumption? CC fitted RBs to my old 1.8K Supersport as part of the R conversion, and the consumption increased from 30-35mpg to around 25mpg. I'm considering going the RB route with my R400D, but I'm a bit chary due to the potential fuel hit.

 

JV

[juleslid]

Hi Martin, that supersport air intake is neat, but I think is designed to connect up to a duct. The ram air thing from the racing R400 doesn't appeal too much lookswise. Am leaning towards going for a (hopefully) neat hole in the side of the bonnet with a grille across it. As I don't have an airbox to pressurise I suspect a ram air intake won't have a lot of effect.

 

John, I seem to remember I used to get something around 35 mpg in normal road use.

I've done 2 tests with the roller barrels, getting 30 and 32 mpg. That was in ordinary road use too, but it can guzzle a lot more when being hammered properly round a track!

Smiles per mile have increased though...

[AdamQ]

Hi Jules,

 

I have an S3 and had similar feelings to you about bonnet holes and what have you. I was also in the same situation with the foam air filter being tight against the bonnet at the narrow end and I didn't like the fact that the induction was taking in hot air from the engine bay.

 

After reading plenty of threads on cold air feeds and seeing one about one Seven variant (can't remember which) which takes a feed from under the radiator, I did the following.

 

- Canted the radiator back by bending the top brackets back and drilling some new holes

- Raised the radiator as far as I could, having canted it back

- Cut a 'postbox' type hole in the nose cone behind/just below the number plate (it can't be seen when looking at the car from any 'normal' viewpoint

- Used some 4" ducting and an in-line air filter to get cold air to a home-made airbox

 

It needs refining slightly, but on the whole set-up seems to work very well and the induction noise is noticeably less.

 

There are some pictures here, here, here and here.

 

As I say, and as can be clearly seen, a little tidying and refinement is required!

 

Adam

[SLR No.77]

Jules, the wire mesh industry is on our doorstep! Might be worth speaking to The Mesh Company and just going for a simple cut-out

 

Stu.

[John Vine]

Quoting juleslid: 

John, I seem to remember I used to get something around 35 mpg in normal road use. I've done 2 tests with the roller barrels, getting 30 and 32 mpg. That was in ordinary road use too, but it can guzzle a lot more when being hammered properly round a track! Smiles per mile have increased though...

Thanks for that, Jules. I must have a right foot made from depleted uranium as I've averaged only 27.5mpg over 32K miles, although that does include trackdays. The best I've achieved is 35.6 (on a gentle D-road tour across France), and the worst is 13.8 (on track). I typically get 30-32 for normal road use.

 

JV

[paul seymour]

Roller barrels is the best money i have spent on my 7, i too have a s v with a larger fuel tank but when out with the penn 7s who mostly are s3's we seem to run out of fuel at the same time so yes we do use more fuel with this upgrade.

That is very interesting to me re a cut out too and wonder if a cut out like a csr has on its nose cone would help.

Any thoughts on that idea or is a cut out to the bonnet the way to go.

Thankyou, Paul.

[juleslid]

Thanks again chaps.

Adam, that's a great bit of modding you've done. Don't think I'll go the pressurised airbox way, the huge Pipercross foam filter on mine is 41cm lomg, 14cm tall and about 10cm deep. Thinking about the surface area there, I would need an immensely wide tube bringing in the air that it could use at full chat. And the filter is already up against the bonnet!

John, must admit I'm not a regular consumption checker. I've normally bothered after extended, gentle road driving when I think I'll get a good number! Never checked it on a track day as I don't want to get tearful in front of the chaps...

Stu, thanks for the heads-up about the Mesh Company. Didn't know they existed, got some good ideas from the website.

There's still plenty of time before I destroy my bonnet for ever (I'll do the job when I take the car off the road for winter) but now tempted by the idea of simply using a mesh vent from CBS, such as the ALIVNT4 on p237 of issue 20. Placed on the left side, close to the front of the bonnet, I think it will allow much improved breathing, without allowing too much water in (which might have happened with my earlier idea of aluminium louvres facing the "wrong" way). Painted black or body colour it should look fairly subtle (car is AM Racing Green).

Jules

[AdamQ]

Jules, I understand your point, but remember that a lot of that surface area that you've got on the foam filter is taken up by the foam that's tying all the little air gaps together (IYSWIM!). Mine made 210.5 bhp (the 0.5 is obviously tremendously important!) on the rolling road with the arrangement shown (and with the nosecone on) - exactly what it's supposed to make as it's running Raceline 210 camshafts ...

 

FWIW ...

Adam

[andygoodliffe]

Jules - intriguing following your post. I'm currently looking at all the options after my Jenvey fit. How ever not being a lard arse I've got even less space than you in my s3. Currently I'm just running pipercross sock filters and I know they are pants. Something needs to be done but what?

Simon at Reverie ltd has been most helpful, so may pay him a visit over the winter months..

Have you got the saw to your bonnet yet?

 

[juleslid]

Hi mate, just had a look at the Reverie website, was unaware of their work, looks like some nice stuff. Was that where you got your fancy new wings from?

As you can see I had lots of good advice about getting air into the throttles, but will probably opt to keep things simple by retaining my huge Pipercross foam filter and putting a grille on the side of the bonnet alongside it. CBS have a fairly neat one 250mm long which shouldn't look too blingy once painted black or AMR green.

Latest thought: there could be a bit of a laminar airflow over that section of the bonnet. Wondering if breaking up the flow with a pair of those carbon blades on the side of the nose would make it easier for air to be sucked into the throttles. Just another excuse to put off cutting into my immaculate bonnet for a bit longer, basically!

 

[andygoodliffe]

Morning. My wings were from Simon at Meteor Motorsport - very helpful chap. The new wing stays were from Carl at Sevenspeed - also more than helpful.

Would have really thought with your motor being an SV you should be able to get a decent cold air intake kit sorted without chopping into your bonnet. I suggest sending a picture of your set up to Reverie. They have excellent knowledge of set up space required and what's available. Got back to me within 30 mins late on Monday night. Impressed.

[juleslid]

Cheers Andy,

I dare say I could fit an airbox into my fatboy engine bay if I put my mind to it.

But I like the induction noise I've got too much. So that's it!

A (very neat) hole in the side should make it even louder...

Those wings look great, but I've got a set of Titon harnesses on the way, so may have to put such things off for a while.

J

[andygoodliffe]

So you've already cut a hole then I take it and the harnesses must be for the impending crash - I hope you've gone for six point. I have nearly gone for six point so many times, 4 point seem inadequate these days.. Big speeds = big crash. If you don't crash your not trying!

[john aston]

Best upgrade I have had on my R400-the difference is extraordinary.I simply do not believe it is only the quoted 10 or 15bhp or whatever; it feels at least two or three time times that. Fuel- no real difference to my surprise- gulps it on track , sips it when touring gently , enjoys a drink when touring briskly.And the noise- sweet baby Jesus...

[John Vine]

Quoting john aston: 

Best upgrade I have had on my R400-the difference is extraordinary.I simply do not believe it is only the quoted 10 or 15bhp or whatever; it feels at least two or three time times that. Fuel- no real difference to my surprise- gulps it on track , sips it when touring gently , enjoys a drink when touring briskly.And the noise- sweet baby Jesus...

Thanks for that, John , you've convinced me. Not that I really, under the skin, needed any further encouragement. I've been corresponding with James Gibson recently, and plan to fork out the necessary moolah in the Spring.

 

JV