Adding Jenveys and airbox to SLR...gains?

[jimmyslr]

I am booked into see DVA to put Jenvey DTHTBs and a Bernard Scouse airbox on the car. This is in place of my "standard", swan-neck, TBs on my SLR. I have an Emerald, verniers (timed properly by Dave last year) and the normal SLR 4-2-1 cat bypass.

 

There are a couple of reasons for this; 1 - "upgraditus", it just sounds like fun, looks shiny and should be more power / better throttle response and 2 - the airbox should improve (ie reduce) noise a bit and hence get me back on Goodwood/Bedford (already have Raceco, but still just over limit when giving it some stick).

 

Presumably many have been here before...what gains (oh, please let there be some) might i see? Do i need to get into things like trumpet length or any other such cleverness?

 

The plan would be a trip to Dave Walker for a proper rolling road session and then I'll leave the car alone (honest)...well at least I will after I've fitted one of those clever looking Freestyle diffusers and a MOG seat.... Will it never end

[V7 SLR]

Sadly...

 

I've done it and I don't think you'll find any gains. The Jenvey's will give you marginally better throttle response, but not massively. You will need loooong trumpets too. The Jenvey's are much shorter than the TB's you've currently got.

 

The airbox definitely quietens things down a bit but if you later change to 1227 cams in conjunction with a head-job, you may find it limiting. You need to be pushing 220bhp for that though. I saw definite differences with it on and off last time I was at Emerald.

 

Unless you're chasing the last ounce of power, the SLR engine is best left with just the Emerald and properly timed verniers. It works well, is very strong and reliable. Mine is also all of those, and yes it gives a bit more grunt, but it's a lot of time, money and effort to get there (which I thoroughly enjoyed).

 

I'd go so far as to say you almost certainly won't find any differences until you pop a set of 1227 cams into a properly sorted head.

 

Your first reason for doing this, "fun" is one not to be overlooked. It *is* fun. Very entertaining to do and if you're struck by upgraditis, ask Dave to give you a price for a Winter head job which includes the porting, valves, gasket set and reassembly (unless you want to do it yourself - recommended). Then you ought to be chasing R500's but with a much more useable power range.

[jimmyslr]

Now that really doesn't help in discouraging me from ongoing "tinkering" and "safety upgrades" (the old stalwart of all reasons for spending big sums on the car rather than the wife, house, upcoming offspring etc) 😬

[frankyknuckles]

thread hijack (sorry!)

 

V7 SLR - does this mean that a set of well setup Verniers on a standard R300 will produce performance gains?

 

www.R300.net

[V7 SLR]

Don't really know much about the R300, but I suspect so. Gains are fairly minor, although noticeable. The type of gain is the "it should have been like this to strt with" type, if you see what I mean...

[martinwhitcher]

frankyknuckles,

 

The answer is YES! the standard cams can be out by quite a lot .

 

Speak to Dave, but it will be worth it!

 

Martin

 

MW 51 CAT

Superlight No.171

[frankyknuckles]

Cheers, I've emailed Dave and will try to speak with him on Monday. Thanks

 

www.R300.net

[donkey kong]

franky ,you beat me to a reply!!!!!! 😬 BUT do let me know what dave says on monday please ,I'm feeling a bulk buy coming on ............................

 

Always driving with a can of WHUP-ASS in the car!!!

[gavinp]

James

 

My MOT woes are well known, and the reason, after advice from Nig. that I got myself an Emerald and a day with Dave on the rolling road. The result - 204BHP and 153lbsft. With swan neck TBs, 4-2-1, and Raceco. Nig. has also persuaded me not to do much else for now, except for maybe verniers. I am a very happy bunny and recent outings at Brands GP and Snett (last Thurs) show I have a bit of a goer.

 

My problem is still noise. Stupidly I booked Goodwood with RMA in Oct, and I am trying to get back to Bedford. Now the looks of my car have been outweighed by safety and performance (SL cage etc.) I don't care about cutting a dirty great hole in the front for an air box.

 

Nig., anyone, any views on what airbox to go for assuming keeping the Swan necks, and whether I will need a re-map? Will noise come down that much - compared to the Noise Killer acoustic foam I already have to reduce induction noise?

 

(Sorry, second half of my post here is a slight hijack but hopefully all adds to the discussion)

 

cheers

 

gav

 

Superlight R #41

[V7 SLR]

Do you have a hole for the induction in your bonnet? I don't and have never had induction noise issues, although my exhaust has come close to the limit on a couple of occasions.

 

I doubt that there is an airbox for the original TB's because they're so long and wouldn't really give you any room under the bonnet to fit it.

 

Oddly enough, moving to the Emerald and verniers (at the same time) changed the sound of my car quite significantly. It became a harder-edged sound, and yet I reckon it was slightly quieter, although I can't imagine how that's possible with more lift on overlap thanks to the verniers.

 

I reckon if induction noise is your enemy that you're onto the right road with your accoustic foam.

[gavinp]

I think the foam does a great job, and now that I have fitted and road tested (at Snett) a manual overide switch for the fan, complete with cool ultra bright blue LED (thanks Chris W for the help), I don't worry too much about the extra heat kept in.

 

My Raceco is great, apart from Titanium is not as tough as I expected and a few fast corners at Brands (with a passenger - not that fat) and the speed humps at Bedford's entrace, have conspired to knock a hole in the back of the bl**dy can! Expensive hole!

 

g

 

Superlight R #41

[frankyknuckles]

do let me know what dave says on Monday please

 

I spoke with Dave Andrews, he recons that the supersport cams (that are in the R300) are always badly timed. He recons that an additional 15lbs/ft of tourque can be gained (11% more than standard) from adding verniers and setting the timing correctly along with better throttle response and driveability. You may not necessarily get more power, but the above gains sound great

 

Your looking at £294 fitted.

 

He does check the cam timing on your car before fitting, ie, offering you the choice to fit them or not if the cam timing is not badly setup from the factory.

 

4 hours work.

 

www.R300.net

[V7 SLR]

I might also add, that even if you can time them yourself, Dave has made a set of brackets to hold the dial gauges (he uses 3 at a time). This removes any flex that you will find when using the standard magnetic stand to hold a dial gauge. Not only that, few people have 3 dial gauges. It takes me ages with my single dial gauge and mag stand to sort out TDC, then one cam's measurement, then back to TDC and to the other cam's measurement... etc... etc. It's a laborious business. Dave's done it at least 2000 times more than me (and I did it a lot of times last year) so he can get a repeatably accurate result with little pain.

 

Well worth the money.