Smaller s\c pulley and right sized belt

[dingo]

Gents:  As Winter approaches, I have a project that may produce some net HP increase.
I've already posted pictures of the new exhaust.
 
You can see from the attached photos that the serpentine belt used to drive ancillaries including the s\c is too narrow
by one groove.  It runs on all pulleys at the outside retainer.  Alignment is OK, but it's just too narrow. 

I think it creates stress. (at least in the writer) and possbly on the bearings in which all these pulleys run. 
In contemplating a wider belt, I contacted pulleyboys (If I was in Australia now, that would cause an uproar)

The nominal ID of the s\c pully installed here is 3 inches.  We're going to try a 2.8 inch ID one, or if wildly enthusiastic a 2.6 inch

(nah ! )

OK, so 2.8 inch ID plus the correct width serpentine. 

This one has dynoed at 254 hp at the wheels with the stock exhaust.
No dyno tried yet for the new exhaust fitment.

Has any other US Honda s\c 300 owner taken a look at their serpentine belts lately?  Are they skinny like this?

[dingo]

How it looks at the crank.  Brammo tells me:

The supercharged Honda belt length is 47.375 inches

[silver]

Dingo, that is weird that it would they would fit it with a belt that was shy on width.  I know that Bottoz' has a custom pulley set up on his ecotec, and the pulley that is on the supercharger now has one extra rib, so even though this has nothing to do with the honda, his car has seen no malfunctions due to the belt not fitting fully on the supercharger pulley (it still is the correct width for the rest of the setup which is why there's no need to change it on his.)

He did see gains by reducing the size of the pulley but since the ecotec has such an issue with heatsoak, and the locked ECU, he's using a smaller pulley than the 300hp original one came with and he's getting about the same power as the original 300 pulley...his ECU is programmed for the 230hp and he's got 220hp at the wheels.

hopefully some of this will help you on your quest...most importantly, as long as you can tune your ECU and avoid heatsoak I'm sure you'll see safe and remarkable results.

[dingo]

Maybe I'll even crack 158.4 foot pounds torque ?
Hold ON !  Hondata ECU is the fully programmable one, so I'll try this slightly smaller pulley first without map change and take it
back to dyno folks and see what has transpired. 

This time, I'll be :
wearing my platform driving shoes,
plus the shims I put under the throttle pedal and also
(surprise surprise) those gains I got by taking up the throttle cable slack. 

Yes, truly a low tech series of HP gains.
The Exhaust and s\c pulley will benefit somewhat. 

Keen to find out.  Cut the conjecture, drop the hammer. 

OK, I got carried away, I guess.

[CalScot]

Standard Honda Pullley is a 7pk (seven ribs) Running a 6pk on a seven ribbed pully is no problem by the way. It will last a little less and as long as it is not slipping, it's not an issue.
Try "Belts for anything"  http://www.beltsforanything.com/site6.php
This is where I got the funky size for my Honda Rotrex kit.

[dingo]

Thanks for the observation.
That's what Brammo had offered too about the 6 rib one being adequate.

The belt was slipping for a short time while I was trying to video a bit of the startup and revving for a
YouTube posting.  Maybe the belt was cold.

I would feel better if it was right sized.  I'll check with local shops first than try belts for anything if unsuccessful.  Thanks, Peter.

[CalScot]

Dingo,
It' should'nt slip, cold or not. That tensioner on the Honda is a beast. If it's slipping, change the belt!
Your belt size will be 7PK 1203mm,  (assuming the belt was measured wiith the tensioner on at least 50% retraction on the spring) Something the factory should be able to get right, right?

[dingo]

Ah, but it was squeaking.  That was the first I'd heard it.  So all the better to swap it out.
I am pleased that the belts can be installed as it all passes under the right engine mount.
Yes 1203 mm is equal to 47.375 inches.
With a slighly smaller pulley, I'm planning to stick with the 1203mm length belt, but go up to 7 peak.
I'm hoping that with such a modest change in pulley size, that I wil not create any adverse effects.
There's no heat exchanger \ intercooler and the boost will be ~ 5% increased only, so the injectors should cope fine.
A little bit here, a little bit there. Might add up to something useful and it keeps me amused.

[CalScot]

Dingo,
The S/C has a seven PK pulley, right? I forgot to ask that.
By the way, 7PK belts are not typical in these auto applications, so a good belt supplier will cut an 8PK down to a 7PK on a special cutter, so expect that as a matter of course.

[dingo]

Yes, 7 Pk = peak,  not counting the retaining flanges on outer extremes of pulley.

[CalScot]

The outer flanges are are different and can't be used I don't think, at least not on my S/C pulley.
The Rotrex S/C pulley is an 8PK. The Honda a 7, as noted before.
One final thing you will want to check is how Brammo mounted your S/C. Make sure they did not use a 6PK because the S/C is out of alignment with the engine belt path and the only thing to fit was the 6PK!
I hate to say it but there is a good chance they did that. Hope I am wrong!

[dingo]

Alignment appears to be OK. 
The belt is running at the outer edge of all pulleys and the inside of each pulley, not covered by belt is showing
by the same amount. 

[maverick1]

Dingo, since you have the Honda Atom why not just pick up a Rotrex kit and be done with it. With that kit you can have anywhere between 350-500hp and have the cool sound of a jet turbine.
If I had known what I know now, I would have opted for the Honda Atom.
Live and learn.
Cheersâ?¢

[CalScot]

[quote="dingo"]
Alignment appears to be OK. 
The belt is running at the outer edge of all pulleys and the inside of each pulley, not covered by belt is showing
by the same amount. 
[/quote]

Dingo, your in luck. Must be the clean living

[quote="maverick1"]
Dingo, since you have the Honda Atom why not just pick up a Rotrex kit and be done with it. With that kit you can have anywhere between 350-500hp and have the cool sound of a jet turbine.
If I had known what I know now, I would have opted for the Honda Atom.
Live and learn.
Cheers™
[/quote]

Mav,
I love my car but the whole mega power thing is a double edged sword. For example, I would not drive my car across country like you did unless I could line up high octane gas along the way (100 typically). If I run too lean, it's BOOM, and that line is very fine. My car is not as reliable as yours because it's on the edge! That extra adrenalin rush comes at a price which is more than just the $$$'s.
I think there is a lot to be said for more conventional NA engine upgrades in conjunction with moderate boost as opposed to just mega boost, which can be like grabbing a tiger by the tail in a never ending spiral of modifications.
I am trying to mitigate the reliability issue by the current round of upgrades it's now getting. Maybe I will be succesfull in getting mines tame enough to satisfy all of it. Maybe I will eventually end up with two Atoms. The current beast for the track and a new 300 for trips to the grocery store.  Only time will tell.

[dingo]

Calscot,  I think you're double checking at some stage, but I thought I'd bring it up again in case. 
Sump baffle.
Then Mobil 1 0W 30 I think it is. Same as for Porsche 997.
and Redline 75W 90 gearbox oil.  None of these steps are going to gain hp, but may contribute to lopngevity \ less wear.
The baffle is an absolute must.