Which trumpets?
Author
Discussion

dbv8

Original Poster:

8,676 posts

250 months

Monday 19th January 2009
quotequote all
Ive decided to forget the credit crunch and spend a little on the plastic ahead of this years events.

I run a Chimaera 450 and use nitrous at the drag strip.
I removed the exhaust and plenum this weekend. I have removed the pre-cats and will be semi-sleeving the box for a little more growl.
I am fitting a thermal gasket under the trumpet base and a 12mm spacer under the plenum.
I already have a smooth elbow between the afm and plenum but will be ordering a smooth pipe through to the filter.
I want to fit flared trumpets anfd see Act have metal ones for £199 or carbon fibre for £249. Are the carbon fibre ones much better? These are standard 38mm which i think will be fine for my set-up.

Any thoughts or advice appreciated before i make the call.

spend

12,581 posts

281 months

Monday 19th January 2009
quotequote all
Get your die grinder on the base and save your money wink

dbv8

Original Poster:

8,676 posts

250 months

Monday 19th January 2009
quotequote all
spend said:
Get your die grinder on the base and save your money wink
On the base?
You talking about port matching to the inlet? confused

spend

12,581 posts

281 months

Monday 19th January 2009
quotequote all
tongue outhew:! you have to remove the trumpets in the oven, rather than replacing with different ones just grind a radius into the base - its called a flared TB famous from the Taraka conversion. You can do other things once the carbide burrs are spinning but thats another story wink

450Nick

4,027 posts

242 months

Monday 19th January 2009
quotequote all
Tim is actually a really helpful bloke and won't try and sell you anything you don't need. I'd give him a call and ask him to explain the difference between the alloy and carbon trumpets. Regarding the blended base argument, Tim has done extensive testing on this and I'm sure will explain the difference, and show you some dyno graphs of trumpets vs blended so you can choose. Basically, the shorter the trumpets the more top end bhp you can achieve due to Helmholz resonator tuning, whereas the longer the trumpet the more low down torque you can achieve. Each is at expense of the other however, so all trumpets are a compromise, I can't remember what Tim's are tuned for but I believe it is upper/mid torque. The Taraka blended bases tend to give around 5bhp at the top end, but they drop a fair bit of torque across the rest of the power curve. For drag racing, I would have thought you'd be after more torque so trumpets would be the way to go.

Hope that helps smile

dbv8

Original Poster:

8,676 posts

250 months

Monday 19th January 2009
quotequote all
I agree with retaining the torque (bhp sells cars torque wins races).
I was looking at the flared trumpets as i think they would help in the more even distribution of the nitrous. I use an injector in the inlet elbow and dont want to go the 'direct port' route this year. I should be able to use 150 bhp of nitrous by 1 injector and get a fair share to each port.

As for working with burrs ive already found and sorted shortcomings in the exhaust manifold flanges. The cylinder heads look like they could use some work but that will be done next winter.