carb trumpets

[swedge]

does the length make any difference to anything?

[John]

It does on higher hp engines so i've been led to beleive. It alters the torque pattern.

[paul james]

I don't think it makes much difference when you have a filter covering them, as that changes the airflow. So I suppose it depends on what type of filter you go for, a foam type that covers the trumpets completely, or those fine metal mesh covers that just sit on the ends of the trumpets. The amount of space in the engine bay will dicatate the size of the trumpets to an extent, have them too long and there won't be much of a gap between them and the firewall - assuming you haven't cut it out. I guess something like 40mm trumpets will be fine, but I'm no expert.

[Bean,]

Longer trumpet's give better torque. The more highly tuned the engine is the bigger the difference. And as said the choice of filter will also have an effect.

[swedge]

http://img.photobucket.com/albums/v308/iliketherain/torquecurves.jpg
http://img.photobucket.com/albums/v308/iliketherain/powercurves.jpg

[MK999]

Short answer yes.

Medium length answer it depends on the engine spec, exact flow rates RPM etc.

Long answer is about 5-6 books long with a few different opinions thrown in.

[Jeff16v]

Not much Space with DHOE For long ones, unless a firewall chop is in order. I like the idea of cold air feed where the heater fan is.

[swedge]

ill be running r1's

[Stuart]

can you even get different length trumpets for them?


easiest answer is try different ones on the RR you are setting up on..... better to try on the road though imho

[swedge]

i dont think you can get ones specificly for r1's but the openeing of the carbs is 45, so if you get trumpets as clost to that as possible and fit some grub screws in to hold in place

[Stuart]

grub screw down the intake sounds fun lol

[swedge]

plenty loctite on there and it wont budge or even some silicone hose would do

[C612DNM]

Longer ram pipes improve low end torque while shorter ones are better for balls out revs / horsepower.
The length also affects the affliction know as stand-off. Full radius are better than cheaper ordinary trumpets.

There are some other designs tested by Dave Vizard back in days when pictures were in black & white.

Trick engines run variable length trumpets.

Your main issue in the Nova engine bay is the bulkhead. Ideal length on a 1300 peaking at 7000 worked out to be 70mm, but that was too long. I had to compromise with 40mm rams on 40's that only left 15mm clearance to the bulkhead. You can suffer resonance problems at different points up the revband by having the trumpet too close to the flat surface (bulkhead) that can manifest as weak spots or rich spots.

It's never just so simple as bolt on and go.