[cjperformance]

Well.... unfortunately, there's a massive problem with belt slip. It threw the belt... and split it in half lengthwise to boot. That was $23 well spent!

I really don't think there's an alignment problem. Checked 3 times.... And I can clearly see things go to heck in the log.

BUT things looked amazing right before it happened.

First run got up to 11.5 psi, then it plateaued and fell off. The follow up run only got up to 7 or 8 psi, then the belt gave up the ghost. So I guess I probably fried it on the first pass and things went downhill from there. Was mainly watching the lambda on my gauge and didn't notice the boost drop in the log until the belt came off.

Someone mentioned belt slip earlier in the thread, and some potential remedies. I'll have to go back and review for notes, but gotta get that under control before I can do anything else meaningful.

At 11.5 psi, though I'm hitting some DI IPW limits. It's tuned rich up there by quite a lot (about 8% rich) because I've never been up in that area of the MAF, but I'm not sure even if I lean it out if it's going to be in the safe IPW zone.

So the solution obviously is the increase the % port either across the board, or at least in that area so I can drop DI %.

[Joshinator99]

Originally Posted by cjperformance

Well.... unfortunately, there's a massive problem with belt slip. It threw the belt... and split it in half lengthwise to boot. That was $23 well spent!

I really don't think there's an alignment problem. Checked 3 times.... And I can clearly see things go to heck in the log.

BUT things looked amazing right before it happened.

First run got up to 11.5 psi, then it plateaued and fell off. The follow up run only got up to 7 or 8 psi, then the belt gave up the ghost. So I guess I probably fried it on the first pass and things went downhill from there. Was mainly watching the lambda on my gauge and didn't notice the boost drop in the log until the belt came off.

Someone mentioned belt slip earlier in the thread, and some potential remedies. I'll have to go back and review for notes, but gotta get that under control before I can do anything else meaningful.

At 11.5 psi, though I'm hitting some DI IPW limits. It's tuned rich up there by quite a lot (about 8% rich) because I've never been up in that area of the MAF, but I'm not sure even if I lean it out if it's going to be in the safe IPW zone.

So the solution obviously is the increase the % port either across the board, or at least in that area so I can drop DI %.

What brand of belt? I found out the hard way about cheap belts… I’d stick with Gates or Dayco in my humble opinion.

[cjperformance]

It was a Gates. WAS....

I might need to go smaller. After some looking theres quite a bit of tension difference in a small amount of movement on that tension arm.

Belt is pretty warped. Thinking that has to be caused by slip and overheating. Might try smaller belt, and maybe one of the Gates green belts. Supposed to be better gripping.

After it warped from heat, guessing thats when it threw off.

[Joshinator99]

Where in the tensioner travel range was it running (before breaking of course lol)…? If the tensioner is not at least 2/3rds tight then that’s not tight enough IMO.

[grampa_ss]

If the crank pulley is stock size, then
I used Bando 8pk1615 for the 3.9/3.7 pulley
and a 8pk1601 Gates RPM belt for the 3.5 pulley.
Never shredded a belt

[cjperformance]

Originally Posted by Joshinator99

Where in the tensioner travel range was it running (before breaking of course lol)…? If the tensioner is not at least 2/3rds tight then that’s not tight enough IMO.

Ill check as soon as i can, but it was close to the old position. I marked the old location of the tensioner with a pencil before i swapped pulleys. The new pulley/belt combo had the tensioner about 1/4 inch lower than the old combo. Thought thatd be close enough, but the old belt had probably stretched.. so maybe the new belt stretched quite a bit and got loose enough.

[cjperformance]

Originally Posted by grampa_ss

If the crank pulley is stock size, then
I used Bando 8pk1615 for the 3.9/3.7 pulley
and a 8pk1601 Gates RPM belt for the 3.5 pulley.
Never shredded a belt

Yeah, stock PC crank pulley. The belt i used was a Gates 8pk1619 (actually K080635 part#).

I'm wondering if you have the auto aduster tensioner, or the manual one where you can control the tightness?

Im going to see if i can get a slightly smaller belt to work. Im going with the idea that the belt stretched enough during the first hour of operation to loosen the tension. I played with the tensioner a lot by hand and even a 1/4 to 1/2" of movement seems to have a lot of impact on tension. So if the new belt started out with the tensioner a 1/4" lower than the old belt, then even if it stretched just a little, i think would have a big impact.

That belt worked fine on my first couple of runs the first day up to 6,100 rpm and 9.5 psi, but fried when i bumped shift points to shift at 6,600 and 11.5 psi.

Dumbass me didnt open the hood between the first day and second day. I might have been able to see whether the belt stretched any after that first day. Or see any side wear on the belt.

If im still slipping and tossing belts after that, then ill have to look at alignment again i guess.

The only thing that is causing me any doubt is the stock pulley had a washer between it and the shoulder of the shaft. I checked and measured what i thought was an adequate amount and decided the washer should stay there with the new hub/pulley assembly, but now having doubts. There were next to no instructions for putting the new pulley on.

[cjperformance]

In the meantime, while i sort out the belt issue... something i came up with to help with MAF adjustments:

I found out the reflex log contains a lot more data than what you choose to put on the graph. If you export the log from the reflex to a csv file, you can selectively export MAF values paired with Lambda Corrected % values. Using some spreadsheet magic i was able to sort and average the correction values by the MAF x axis values defined in both the E92 and Reflex. It spit out a set of percent corrected by MAF x axis increments very close to what youd see on a MAF EQ Error Ratio chart in HPT.

Interestingly, the values it spit out for average adjustment at specific MAF ranges were very close to my custom PI-MAF table in HPT... which is essentially an EQ Error % table, but hardcoded to get the pct difference between actual lambda and my desired .82 lambda. Needs to be tweaked still to discard non-WOT data, but i can manually copy the ranges I need. Since commanded lambda in the E92 is skewed due to pulling PE to supplent the MAF for tq mgmt reasons, i can no longer use commanded EQR vs Actual EQR, thus the hardcoding to .82.

I think the fact that the wideband has to read downstream before the reflex can make adjustments still allows the EQ Error Ratio process to work. Ill have to try few iterations of adjustments this way and see if it allows things to get dialed in in a reasonable way, and see if the correlation holds as i get closer to ideal.

I did my last round of adjustments this way, but the belt issue really invalidated any data i collected.

[cjperformance]

Ordered a K080630. Should be about 1/2" smaller than the last belt. We'll see how that fits. If it seems like it is working size-wise, I'll probably try to get the HD version (green belt), or maybe a Gates RPM belt. Sounds like the RPM belt would be a good idea.

Not expecting to use the standard belt for long, but it was cheaper and faster to get and try for sizing purposes.

[grampa_ss]

Originally Posted by cjperformance

Ordered a K080630. Should be about 1/2" smaller than the last belt. We'll see how that fits. If it seems like it is working size-wise, I'll probably try to get the HD version (green belt), or maybe a Gates RPM belt. Sounds like the RPM belt would be a good idea.

Not expecting to use the standard belt for long, but it was cheaper and faster to get and try for sizing purposes.

My tension adjustment is manual. If you go with the RPM belt, remember…the belt has no stretch. Do your research on adjusting it. You just barely snug it up. Exact opposite of the standard belts.

[cjperformance]

Originally Posted by grampa_ss

My tension adjustment is manual. If you go with the RPM belt, remember…the belt has no stretch. Do your research on adjusting it. You just barely snug it up. Exact opposite of the standard belts.

I have a spring loaded tensioner.

[laynlo15]

You should just barely be able to get the belt on, it should be that close to running to the end of the tensioner. I'm saying should be a tight fit.

[cjperformance]

Originally Posted by laynlo15

You should just barely be able to get the belt on, it should be that close to running to the end of the tensioner. I'm saying should be a tight fit.

Got it. The K080630 should be here today. We'll see where that puts things.

Tried to do things scientifically by calculating the difference in pulley circumference and multiplying by the % of wrap, but in hindsight i should have erred towards the tighter side. The theoretical difference was 1", which would have been the 63.5" since the old one was 64.5".

The K080630 will be a total of 1.5" smaller than the original belt.

There's another belt increment down from this one too, a K080626... another 1/2" smaller if this one doesnt work out.

Ill probably drop shift points a little again, do a couple tests, and check the belt more often this time around. Seems like last time it probably fried right away after the first pull.

Im glad i marked the pulley location before i took the old pulley and belt off. It has been very helpful to have that reference.

[laynlo15]

You can buy an Lt5 tensioner from Mike.