Jump to content
Click here if you are having website access problems ×

Trumpets (42mm dia.) to suit Jenvey TBs


Smithy77

Recommended Posts

As above, looking for some adjustable trumpets but may also consider fixed length 90-100mm (or longer and can be cut down).

My car is going for a mapping session on the rolling road next week. I am currently burrowing a set of adjustable trumpets from a friend as my old fixed length trumpets are too stubby at about 45mm long. We will have a play with trumpet length on the rollers and will determine the best length. After this I will know exactly what length I require, but just thought I'd ask around in advance to see if there is anything lying about...

Thanks

Edit: Updated with trumpet length required

Link to comment
Share on other sites

Excellent! I bought the car with a 4-1 exhaust and it was last mapped at emerald with a massive flat spot in torque between 3000-5000rpm. It had the effect of a turbo kicking in at 5K rpm. I've since swaped the exhaust for a 4-2-1 VHPD/SLR exhaust, fitted a lightweight flywheel and burrowed these adjustable trumpets. It produced the best result with 95mm trumpets and I've gained 5-10bhp peak and 10-15bhp in the midrange. Totally transformed the car, and the torque curve is now a near symetrical gentle arc!!

Link to comment
Share on other sites

Without the air box and just twin filter socks it's quite a bit louder and throatier. Suffice to say I won't be using the airbox unless a trackday noise limit dictates!

I only saw back to back BHP curves with the airbox. I think you can assume the effect on torque is relative to the effect of power.

I used JKM in Portsmouth. Emerald recommend them for emerald mapping in the south, but worth noting JKM's dyno under-reads relative to Emerald's by about 5%

Link to comment
Share on other sites

  • 2 weeks later...

Sounds like an excellent result Pete - what's peak power now? 

Previous owner (before me) had the same experience with the airbox (when the car was mapped by Emerald) hence why I never ran it with the airbox (I also liked the noise!).  I did 4-5 trackdays in the car like that and never came close on noise limits, so you should be fine for induction noise. 

Link to comment
Share on other sites

Hi Neal, Pete is away for a few days so might not reply. I'm the one who came down to yours with him when he came to test drive it. From memory it was making 187.2 bhp on the rollers. Pete took me out for a spin in it a few days ago. All I can say is ... bl**dy h**l it's quick!
Link to comment
Share on other sites

Pete does jokingly miss his turbo-like torque curve the car had previously. But he says that it's a totally different engine with smooth power and dollops of mid-range, ideal for road use. Think it made 155lbft peak in the end. A 4-2-1 manifold, longer trumpets and remapping has made a huge difference, combined with all the work Andrew has done to the bottom end to stop it from exploding.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...