airbox on an SLR

[gavinp]

I would appreciate any suggestions for an airbox on the VHPD. As ever, trying to bring the noise down, so any feedback on noise reduction would be useful as well.

 

thanks

 

g

 

Superlight R #41

[Jason Plato]

If you have the old style swan neck throttle bodies then you cant buy an airbox off the shelf to fit .

 

You could make one fit if you are willing to cut a hole in the bonet for the box to poke out of .

 

A small reduction in noise can be had by glueing a section of felt on the underside of the bonnet facing the airfilter .

 

Simple answer is to go to noisier venues

 

Lotus 7 Club Speed Champion 2003

South Wales Area Organiser

C7 TOP

[jimmyslr]

Gavin

 

I've been thinking the same over the last few weeks and have concluded that it's either a hole in the bonnet or different throttle bodies. The latter sounds a bit drastic, but look at it like a silver lining; I quite fancied some DTH Jenveys anyway! They are nice and short so a normal airbox will fit (Bernard Scouse job), plus they will liberate another 10 bhp by doing away with the convoluted swan-neck design of the original ones. It will be quieter and faster - not bad!

 

There seem to be no neat/easy answers from my research.

[gavinp]

Bernard Scouse job 🤔

 

Superlight R #41

[jimmyslr]

Gavin

 

I mean an airbox made by Bernard Scouse. Have a look at DVA Power website for references/pics and a link to Bernard's website (Auto Tecknix I think it's called). Suffice to say it won't fit to your existing set-up without a hole in the bonnet. Neither will the Caterham solution, which is designed for the R500 and its throttle bodies.

 

DVA's website also has the Jenvey TBs that will be finding their way onto my car in a few months time!

[gavinp]

Dave, isn't there a slight fire risk with felt 😬

 

Superlight R #41

[gavinp]

Jimmy, so with the Jenveys you can get an airbox to fit without cutting holes? Might need to follow your lead on this, especially if I fail Bedford on the 24th ❗

 

 

Superlight R #41

[V7 SLR]

Opting for Jenvey's in place of the swan-necked SLR TB's will not liberate any more power. I'm convinced that my original swan-necked TB's were fine well up to 220bhp. The advantages are in that the throttle plates are closer to the valve, making throttle response much crisper.

 

I made very many changes to V7 over a long period (haven't finished yet) and each time I have checked the results on the Emerald rolling road. The single biggest change I noted was the change from MEMS to Emerald. That in itself brought about a far crisper throttle response. Then changing the camp ulleys to verniers brought mid-range traction and "driveability" to the mix.

 

When you change the ECU you will notice a change in throttle sound. I kid you not. Then, when you change the pulleys to verniers (these are THE first changes you should do to an SLR, even if you go no further) you will notice yet another change in throttle sound. Deeper and more "motorsport" if such an word exists in that context.

 

I now have the full DVA/Emerald package including Bernard's airbox, and I'm not convinced that my car is any quieter than before. I never had a hole in my bonneet, and I still haven't. The damn thing is still very loud.

 

You're welcome to talk to me about changes if you need an opinion. I now have the following spec above the standard SLR spec:

 

*arrowright*Full porting job, courtesy of DVA

*arrowright*1mm larger valves for inlet AND exhaust (not sure whether there is anything to be gained from larger exhaust valves except that I ditched the standard Rover valves for Paul Ivey wasted stem ones).

*arrowright*1227 cams (don't believe people who say the car is harder to drive as a result. Mine's a perfect shopping car if I so choose).

*arrowright*Jenvey's, including airbox (the standard trumpets are too short though. I think I'm going to engineer a much longer trumpet "solution". They need to be at least twice the length).

[yankeedoodoo]

What is the current thinking on the subject of length from the head to the end of the trumpet? How many inches is optimum? And where is the performance gain most noticeable? Would anyone care to shed some light on that subject? Thank you very much ❗

[jimmyslr]

V7

 

From earlier threads I was under the impression that losing the rather tortuous swan-neck did give a power gain; I had a feeling that DVA had said something similar, but don't quote me. All hearsay so I would very be interested in a chat.

 

I have the Emerald and verniers, again courtesy of Dave. I think I know what you mean re sounding more "motorsport". It's something you can hear in the mid-range.

 

If you drop me you number and when you're around I'll give you a call to pick your brain

 

James

[oilyhands]

I've converted 7 or 8 SLR/VHPD engines from the older style TBs to Jenvey DTHTBs, mostly they have gained horsepower although it's not as much as 10BHP, certainly they have all experienced a much better idle, razor sharp progression and much improved throttle response.

 

Nigel's original TBs had undergone some fettling on the manifold both at the TB end and the head end which would have brought some improvement to the original setup so he may not have seen quite so much of a clear gain.

 

The airbox kit is available from myself or from Bernard direct and now has the option of longer (90mm) trumpets which pick up the mid range torque.

 

Oily

[jimmyslr]

Oily, I will definitely be in touch. It's probably a project for late May / June. I am loathe to mess with the car until after my Europe track trip in early May.

 

James

[Big Brother]

I don't want to hijack Gavins thread but I have a question thats bugging me.

 

Would an airbox have any (positive) effect if it was fitted to a car running carbs?

 

Steve

 

Se7en-Up!

Not going to you know where with you know who in 2004 😬