ATI Harmonic Dampner
 

So I've been searching the forum of a thread about this product but there doesnt seem to be one so I guess I'll kick things off. I'd like to know from those of you with experience (total newb to tuning here) how will the 10% underdriven aspect affect the car? Will I need a tune because of it or not really since these only affects the accesory belt? Any and all constructive information/ advise welcome, just please dont troll, thanks!







http://www.atiracing.com/products/da...dam-subaru.htm
this is the link for the product and heres a pic too

Different manufacturer, same idea:

http://www.ft86club.com/forums/showthread.php?t=89734

I looked over that thread, the concept is similar but that pulley isn't Under driven or if it is, they don't state it anywhere. I am interested in knowing how this Under drive will affect the car so that thread can't help me.

The ATI pulley is not an underdriven pulley.

Will it help on a stock engine? Likely not.
Can it hurt? No.

Would it help on a monster built high HP car? Likely yes?

Will you feel a difference if you replace the stock pulley with a lightweight aluminum pulley? No.

This was quoted from that link I posted:




Subaru BR-Z Super Dampers
http://www.atiracing.com/images/bline.gif

ATI's Super Damper (Part # 918482) for the Subaru BRZ and Scion FR-S 2.0L boxer engine is designed for both street and high performance racing applications. The new aluminum-shell, steel-hub damper features a 10% underdriven belt drive that works with the OEM belt set-up. It's a direct fit replacement for the stock OEM unit and is better capable of handling a wider variety of driving habits that owners will put their new cars through. OEM dampers are optimally tuned to a narrow band of perceived normal driving conditions and do not perform well outside of those limits. The ATI Super Damper can handle any engine speeds and driving conditions that get thrown at it to better protect your engine. ATI Super Dampers provide balanced dampening of torsional crankshaft vibrations through all RPM ranges and exceed SFI 18.1 Safety Certification for competition use.

Why would they say it's Under driven if it isn't?

You sir, are not correct. The ATI IS an under drive pulley. I contacted them and asked if they would produce a standard size one, and they said a stock sized ATI pulley wouldn't fit. I am supercharged and there is plenty of room for a much larger than stock pulley. I want stock sized so I do not under drive my supercharger. They won't make it!

I stand corrected.
When we talked about these pulleys last year on this forum they were not underdriven at that time.

Maybe they offer it in both types now?

I was interested in a stock sized one due to my supercharger. They said it wouldn't fit and they wouldn't make it. I sent an email to them from their site and that is what they told me. I have one on a mini r53 and it really helped that engine. I was disappointed.

Maybe I am remembering the fluidamper?
http://www.ft86club.com/forums/showthread.php?p=2280212

I think so.

I'll be running one this race season with an under driven alternator and water pump pulley as well. I'll keep everyone posted on the results.

I had one of these on my 2zz. Loved it. Was willing to finally go past my 10k rpm limit after some rigous data logging. Pro tip. If you see a race team running a non sponsored damper over the free sponsored damper. You can bet its a better part.

crazyfrenchbiker: can you tell, where you got underdriven pullies for alternator/water pump (guessing that those need to be larger diameter, on contrary to smaller diameter under-driving crank pulley)? For those i see many bling ones offer lighter weight, but IIRC none was underdriven.

Question: how does the ATI Super Damper compared with the Fluidampr?

I know:

(1) Prices are similar, lowest from $355 to $375;
(2) Fluidampr is slightly heavier at 5.8lv, vs 3.8lb for the Super Damper;
(2) Super Damper is 10% underdrive.

I read from other Subaru forum that the fluidampr appears to be better built, and users seem happy. I didn't not read or heard any user feedback on the Super Damper.


It seems to me the Fluidampr will provide greater damping and (hence smoother engine operation). The 10% under-drive of the Super Damper should yield a little more power without creating additional vibration.

Based on the above, am I correct to assume that for street driving, the Super Damper may provide more fun; but for tracking or race, the Fluidampr may be more suitable for high-rev operation.

I would appreciate if any with first-hand experience with both items could comment and compare these two dampen crank pulleys.