Straight cut v helical on centri.

[Veteran]

So was having a discussion with a mate that straight cut are more efficient and produce less heat. So basically you get more power out of a straight gear centri. He reckons the difference is negligible.
Apart from sounding wicked, what’s the opinion on efficiency ?

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[Jackson1320]

So was having a discussion with a mate that straight cut are more efficient and produce less heat. So basically you get more power out of a straight gear centri. He reckons the difference is negligible.
Apart from sounding wicked, what’s the opinion on efficiency ?

I would not think that there would be enough difference in efficiency to effect someone’s decision. Also straight cut gears rattle and sound like they are grinding themselves to dust at low rpm’s

 

[illtal]

I would not think that there would be enough difference in efficiency to effect someone’s decision. Also straight cut gears rattle and sound like they are grinding themselves to dust at low rpm’s

I agree, It's probably negligible, if any on a street car. The noise would drive me bat shit crazy though. It's one of the reasons I didn't think about a PC when I was looking at boost. Didn't know at the time there was a "quiet" option.

 

[Jackson1320]

I agree, It's probably negligible, if any on a street car. The noise would drive me bat shit crazy though. It's one of the reasons I didn't think about a PC when I was looking at boost. Didn't know at the time there was a "quiet" option.

If anyone has the straight cut gears and doesn’t want to hear the rattling/grinding noise. If you pulley down the procharger to about a 3.7 or smaller the grinding/rattling noise goes away 99% of the time. sometimes with the 3.7 you have to bump up your idle rpm. But if you go 3.6 3.5 the noise will go away without needing to change the idle

 

[Nctong01]

Negligible. In all honesty I like the way the straight cut sounded on my setup…am I the odd one out?

 

[illtal]

Negligible. In all honesty I like the way the straight cut sounded on my setup…am I the odd one out?

that shit sounds like a case full of gravel in it on camera. FOOK that.

 

[80FoxCoupe]

F1A94 here (straight cut obviously), and it loud. Everything about the car is loud. Blower, BOV, exhaust etc. But that's what this car is about for me. Its not a daily so it can be loud, its no prob.

 

[illtal]

F1A94 here (straight cut obviously), and it loud. Everything about the car is loud. Blower, BOV, exhaust etc. But that's what this car is about for me. Its not a daily so it can be loud, its no prob.

In that case it's not a problem I agree.
But I have a street car though.... It's a consideration when riding down 75 ,85 or 95 for 7 + hrs.

 

[Mach1soldier]

I have straight cut and honestly never notice it except at idle when standing in front of car.

I guess if you have factory exhaust you might notice.

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