Air Pump removal, Something you need to know.

[Chadwick]

The first thing most people do when upgrading their car is to remove the Air Pump and throw on some under drive pulleys. The problem with this is now the contact patch on the water pump pulley is greatly reduced and most find that they can turn it with their fingers even with the belt tightened above stock tension. What most people then do is over tighten the belt to stop the slipping.

The rotary engine uses hydrodynamic journal bearings to support the eccentric shaft. The way it works is by flowing oil under pressure between the bearing surface and the shaft and basically “floating” the shaft through the fluid dynamic effect. Increasing the lateral load to one side on the shaft reduces how well the journal bearing can do its job of “floating” the shaft and results is metal on metal contact and accelerated wear. Over tightening the belt creates just this type of lateral load.

Pictured below is just one example of excessive bearing wear caused by running under drive pulleys without the air pump and over tightening the belt to compensate. The first picture is of the front bearing on two motors with a similar history. Both ran Mobil 1 10w30 most of their life and were autocrossed. The 99,800 mile motor stayed in stock form until it met its end due to a water jacket o-ring failure. The 66,000 mile motor had the air pump removed and under drive pulleys install around 53,000 miles. It also met its end to a water jacket o-ring failure.

The front stationary gears are in their correct orientation so what you are looking at is the top of the bearing as it sits in the motor. The copper color area is the wear.

http://www.tweakit.com/rx7/b1.jpg
http://www.tweakit.com/rx7/b2.jpg

The next image is of the rear stationary gear bearing. The picture is upside down to the way it installs in the motor so you are looking at the bottom of the bearing surface.

http://www.tweakit.com/rx7/b4.jpg

Close up of rear bearing wear:
http://www.tweakit.com/rx7/b5.jpg

As you can see the bearing wear is exceptionally worse on the 66,000 mile motor and the wear pattern on the bearing clearly shows the extra load applied by the lack of an air pump or idler in its place is the cause.

The only solution is to keep the air pump or replace it with an idler pulley. Currently there are three companies that have a solution available now or in the near future. They are:

Pineapple Racing (http://www.pineappleracing.com/index.asp?PageAction=VIEWPROD&ProdID=146): $179.00 + shipping
Requires removing two bolts out of the water pump housing to install.

http://www.pineappleracing.com/ProductImages/fdidler/Resize%20of%20IMGP2241.JPG

Tweakit Racing: (http://rotarycarclub.com/rotary_forum/showthread.php?t=5627) $142.00 shipped
Bolts to Air Pump stock mounting points
http://www.tweakit.com/rx7/pulley.jpg

Garfinkle Motor Works (http://rotarycarclub.com/rotary_forum/showthread.php?t=2024): Will be released soon. Price to be determined, but estimated below $200
Bolts to Air Pump stock mounting points
http://www.tweakit.com/rx7/garfinklep.jpg

[jkstill]

A worthy mod for those without the air pump.

FYI a local tuner (Portland OR) actually cracked the E-shaft by using too much belt pressure in his personal 600+ HP car.

He probably added the pulley following that.

I would be in on the group buy, but already have Pineapple's kit.

[Brent]

*cough* shameless plug *cough* :D All kidding aside, this is a great product. I had a chance to check it out at the shop a while back. I will more than likely be getting one of these in the near future. Dan and crew(Brian and Andrew) are very knowledgeable... just about as knowledgeable as they come. Dan is one of the few people that I will let work on my car due to piece of mind that it is going to be done right.

[dinosaur]

Dan is one of the few people that I will let work on my car due to piece of mind that it is going to be done right.

When my OE motor "met its end due to a water jacket o-ring failure", Dan was top on my list of builders for that reason. I'm going to get one from Tweakit because they're so close, and he can "supervise" my install.

[proz07]

as far as these go thats all well and good but some of those "idler" pullies may get in the way of peoples single turbo's. so im kinda curious if anyone has a replacment waterpump pulley that has ribs in it to run the belt around it instead of on the back of the belt? wouldnt the ribbing give you the extra "grip" you need to prevent slippage at the correct belt tension?

z

ya sorry guys i thought about this one for like ten minutes before still posting it and then did anyway....oops

BUT i do have a picture on my home computer that has it run exactly this way so maybe he has a different impeller or is just waiting to blow his motor i wish i could post it here as the rest of the setup is pure track...

[David Jerome]

as far as these go thats all well and good but some of those "idler" pullies may get in the way of peoples single turbo's. so im kinda curious if anyone has a replacment waterpump pulley that has ribs in it to run the belt around it instead of on the back of the belt? wouldnt the ribbing give you the extra "grip" you need to prevent slippage at the correct belt tension?

z

It would run the water pump in the opposite direction ;)

[AzCamel]

i would love one but it seems that with the GT42 i have little to no options when it comes to this, the only one that i think might fit ix the pineapple one, it seems small but im still not sure it will fit.

[hades]

I have a question: Don't most people remove the air pump to make room for piping or a single turbo?

Will Garfinkle's kit allow for this?

Thanks for the post this is really good info.

[Chadwick]

i would love one but it seems that with the GT42 i have little to no options when it comes to this, the only one that i think might fit ix the pineapple one, it seems small but im still not sure it will fit.

It just depends on how your single is mounted. On Brent's single turbo car there was about .0003" of clearance between the thermostat housing and the turbo :D. None of them would have worked for his.

Dan

[sbrian2]

When my OE motor "met its end due to a water jacket o-ring failure", Dan was top on my list of builders for that reason. I'm going to get one from Tweakit because they're so close, and he can "supervise" my install.

Dean, I think those are actually your 99K bearings in the picture. Your motor was surprisingly nice inside when we disassembled it.

[Signal 2]

I have a question: Don't most people remove the air pump to make room for piping or a single turbo?

It's not just for single turbos anymore. ;)
I still run stock twins, but for me the point of removing the airpump was for (after emissions delete) the room, weight reduction, convenience and looks. It's been said before, but the advantage for an idler pulley is to keep the stock belt in full contact with the waterpump without having to go to an over-sized (under-drive) pulley set. I autoX but don't track. So I don't spend extended periods of time at high RPM and I don't have a need for the under-drive aspect. Same situation for guys that only street their cars. Not to mention the possible issues during periods of heavy electrical loads at idle.

Chadwick's post is just more reason why I'd rather spend my money on a good idler pulley than an underdrive set. Although I hadn't considered accelerated bearing wear, I have personally seen a guy way over-tighten the belt on his under-drive pulley set because it kept squalling at cold start-up. You could have played a tune on the belt, but hey...they were much prettier than mine. :D

[dinosaur]

Dean, I think those are actually your 99K bearings in the picture. Your motor was surprisingly nice inside when we disassembled it.

Great. I won't change my driving habits then.
redline, here I come :driving:

[Chadwick]

Great. I won't change my driving habits then.
redline, here I come :driving:

lol!

[RedX7]

I just put my name on the GB for your idler pulley. Can't wait for this to go through!

[TRISPEEDFD3S]

hey they look like it could fit with a single on the tweak it set...

[Chadwick]

hey they look like it could fit with a single on the tweak it set...

Really depends on how the turbo is mounted and how big it is. Had a little brain storm starring at the front of a motor this weekend and think I have an idea for one that will work for a single.

Dan

[TRISPEEDFD3S]

Get err done Dan! Make it fit with an A Spec GT35R long runner kit. Haha!

[hsitko]

That is pretty amazing. I was talking to rob at pineapple racing about this a couple of years ago. Its actually why i bought his air pump elimination kit. He was telling me that he actually had one that broke the front of the eccentric shaft clean off because the person tightened the belt so much! Man some people huh? I'm surprised that greddy designed their "kit" the way that they did. Chadwick, pat yourself on the back for designing a part with more forethought and a better design than the famous greddy. You might want to contact them and try to sell them your design. Just saying.

[Ranger]

Wow, thanks for the info all. I have the G'reddy underdrive kit on mine...came on it when I bought it. After I got my car back from being stolen and had the motor torn down, I was told that the eccentric shaft was trashed. I heard that was very uncommon, but I guess I know why now. What's this talk of a group buy for an idler pulley? Also, since I have the underdrive kit, how hard would it be to switch to an idler pulley?

[Brent]

http://rotarycarclub.com/rotary_forum/showthread.php?t=5627

[Doc-1]

This is a lot of good information here!!!!! Thanks guys

[Chadwick]

Group buy for the Tweakit pulley will end on Jan 15th. Get it now while it is cheap.

http://rotarycarclub.com/rotary_forum/showthread.php?t=5627


Dan

[Garfinkles Motor Works]

The pulleys are ready for my idler, I should pick them up Wensday .My design will work for cars with twins .Dans design will work for cars with some single turbo set ups and twins .

[Chadwick]

Here is the prototype of the single turbo version of the kit we test fit today.

http://rotarycarclub.com/rotary_forum/attachment.php?attachmentid=4011&stc=1&d=1232845929

http://rotarycarclub.com/rotary_forum/attachment.php?attachmentid=4012&stc=1&d=1232845929

The pulley will look like the pulley in the original kit; we just used the alt. pulley for fitment.

Here is a picture of the pulley kit that is shipping now. I polished mine and will offer polishing of the kit for an extra $25. If you want yours polished let me know before they ship.

http://rotarycarclub.com/rotary_forum/attachment.php?attachmentid=4013&stc=1&d=1232845929

Thanks,

Dan

[TRISPEEDFD3S]

VERY NICE! How much is the single version and it will fit with a seq twin setup right?

[Chadwick]

VERY NICE! How much is the single version and it will fit with a seq twin setup right?

Thanks! Group buy price is $178 brushed finish or $200 polished, shipped in the US. Sure it would work with twins or single, but the twins version cost less.

Scroll down to Tweakit Racing in the vendor section and there is a group buy going on.

Dan

[proz07]

so the single version uses one of the waterpump studs for mounting? is that right? only reason i ask is my studs are just long enough for the nuts on them much less a bracket too?
z

[Chadwick]

so the single version uses one of the waterpump studs for mounting? is that right? only reason i ask is my studs are just long enough for the nuts on them much less a bracket too?
z

It mounts to the bottom bolt, a new longer bolt will be provided in the kit.

Dan

[ObliqueFD]

Chadwick, have you compared bearing wear on engines with light weight flywheels? I would think you would see similar results.

I plan on picking up your idler pulley sometime after I get my auto to manual swap done.

[sbrian2]

Chadwick, have you compared bearing wear on engines with light weight flywheels? I would think you would see similar results.

I plan on picking up your idler pulley sometime after I get my auto to manual swap done.

Both sets of bearings pictured were from cars with light weight flywheels.

[proz07]

It mounts to the bottom bolt, a new longer bolt will be provided in the kit.

Dan

cool what about a belt does it come with a belt? or will i have to get my own and whats the length for the single version?
z

[sbrian2]

cool what about a belt does it come with a belt? or will i have to get my own and whats the length for the single version?
z

From the group buy thread:

This is now an official group buy for the single turbo design kit. Price will $178.00 shipped in the continental United States for brushed finish and $200 for polished. The kit will not include a belt. The instructions will include the common size needed for stock and under drive pulleys.

The reason I'm dropping the belt from the kit is there are just too many combinations of pulleys for it to be cost effective for me to provide them. Plus if it doesn't fit, you still wind up going to a local auto parts store or wait for me to ship a different size.

If you are outside the continental United States, send the $178 ($200.00 polished) and I will send you a PM if there are any additional shipping/fees once I have a chance to check rates.

[Chadwick]

cool what about a belt does it come with a belt? or will i have to get my own and whats the length for the single version?
z

It does not come with a belt, I have found that there are just to many versions of pulleys that people are running to try and keep up with all the possible sizes. The instructions will include the belt size for standard stock and under drive setups.

Thanks,
Dan

[proz07]

got it sorry i missed that part. ill be in contact once i verify where my single will end up sitting when installed.
z

[Garfinkles Motor Works]

Dan .I have some of my design Idlers ready ,as you know they are for the cars with twins . They will use the stock belt and adjust like stock .Chad will post pict soon .Both of your designs look gooood . Do you have any picts of your rats nest.

[jinxtacy]

I know this is kind of grave digging, but I was wondering if there is any long term feedback on these idlers pulley kits and if any are still in production. Looking to get a kit ASAP. Thanks!

[Garfinkles Motor Works]

I have them ready to ship. It will work with some single turbo setups .My pulley has a double row bearing so it will not twist out of plane .The brackets are steel and will not flex and is fully adjustable Has any one with my idler had a failure ? Let us know .

[Garfinkles Motor Works]

I have idlers ready to ship ,they have double row bearings so they do not twist out of plane .The brackets are steel and will not flex .The unit is fully adjustable .If any one has had a failure let us know . See my venders section ,Garfinkles Motor Works .

[sbrian2]

The Tweakit kits are still in production and the single turbo kit will fit all applications and we still offer the original twin turbo kit as well.

[Signal 2]

I've had David's (Garfinkle) pulley for 2 or 3 years now with no issues.

http://i1126.photobucket.com/albums/l608/Sgtblue/GarfinklePulleyInstall009Medium.jpg

[Doc-1]

Just ordered one myself