Tb Size And What Power They Are Good For.......

[maxi 36 1 Cars]

Right, heres the question.

 

In the quest to find my missing BHP (big cc huge spec gti6 lump- est 260-270BHP made 241BHP 181Ibft-202BHP@wheels) I have had a custom manifold made by maniflow, which im sure will help things out a lot. However, every other similar spec and power engine seems to be running 48mm TB's as opposed to the 45's im using. Can anybody see any great benefit in changing?

 

Im sure I have heard 45's are good for up to 260BHP???

 

Enlightenment?

 

Cheers chaps,

Maxi

[Baz 421]

I can't see it making a huge difference tbh mate. There was a good article/report by Dave Walker about different body sizes somewhere, i just can't find it!

Edited June 12, 2010 by Baz

[crf450 0 1 Cars]

45mm TB's are definitely good for at least 270bhp.

[sideways danny 0]

I dont think you're missing any power really. That's a fantastic figure, probably on a more realistic dyno than others. I've heard huge figures, been in cars and been seriously underwhelmed. Cars that have claimed 240-250bhp I've seen be very much improved with better ECUs and mapping, and make far lower figures than before. Dont believe the hype. Mi16s dont make 270bhp

 

45s should be perfectly capable of what you want, remember air speed is also important. A well designed tapering inlet tract will give far better results than just bigger throttles.

 

Having said that, I am going to be using 48s on my car, because i got them stupidly cheaply. Using 42s on another build and very confident it will make the targets we've set or breaking 200bhp.

 

 

Where/what dyno did you have it tested out of interest?

Edited June 12, 2010 by sideways danny

[Rippthrough 98]

They'll be fine at that sort of power, provided the rest of the inlet tract is matched properly, switching to 48's might get you, oooh, about 0.2bhp extra.

 

They don't start getting restrictive (as in in the order of a couple of bhp, nothing you'd really notice) until about 300bhp+

[maxi 36 1 Cars]

Thanks for the replies chaps!

 

Danny, you are preaching to the converted mate, I couldnt agree with you more. So many wanky dynos out there claiming silly power figures.

 

Just for the record it was mapped by Chris Todd @ torque of the devil couple of years ago, then tweaked a year ago.

 

I would like to see 250BHP out of it this time and be around the 200Ibft of torque mark.

 

Maxi

[sideways danny 0]

Chris knows what he's doing, very good mapper. Did a supercharged viper there with him a couple of years ago. He wont have bulls*itted you on power when i worked at Omex, he was one of the only recommendations we made externally. Now I would send people to K-tec (KTR-sport) as Andy who i worked with at Omex is there. Chris is a very close second choice.

 

I think for torque you'll be hitting a brick wall. It's an NA 4 pot afterall, the only way you'll really get more horsepower (peak numbers) is if you make gains right at the top of the rev range. If you want the car to be faster, concentrate on midrange gains, that's where you'll be using the power to get you to the higher rpm. Probably going to be clever cam choice and trick timing to achieve that.

Edited June 14, 2010 by sideways danny

[maxi 36 1 Cars]

Chris knows what he's doing, very good mapper. Did a supercharged viper there with him a couple of years ago. He wont have bulls*itted you on power when i worked at Omex, he was one of the only recommendations we made externally. Now I would send people to K-tec (KTR-sport) as Andy who i worked with at Omex is there. Chris is a very close second choice.

 

I think for torque you'll be hitting a brick wall. It's an NA 4 pot afterall, the only way you'll really get more horsepower (peak numbers) is if you make gains right at the top of the rev range. If you want the car to be faster, concentrate on midrange gains, that's where you'll be using the power to get you to the higher rpm. Probably going to be clever cam choice and trick timing to achieve that.

 

 

Been going to Chris now for years, first made contact with him when he was at PE and to be honest, wouldnt think of taking a car anywhere else. As you say, Omex recommend him personally.

 

Lest see what happens this time around.

 

Maxi