KR Trouble with 3.6" SC Pulley

from: https://rivperformance.editboard.com/Series-II-Engine-Transmission-f4/Cats-downpipes-etc-p16052.htm#16052

To the topic... hooked up the LS1M and went for a drive in gauge mode, just observing KR and IAT. Cool here today, IAT's were at about 60deg, ambient of 50. With my current mods, I'd expect to be able to run a 3.6 w/o any KR, but that just isn't the case. After the 3.6 install, I saw 5-6 peak KR without even going WOT. Now with the PEM, 3" DP and hi-flow cat installed, it's not any better. I actually pushed closer to WOT, and hit a high of 8deg of KR.

So yes, I need to get some tuning work done. Think I've found someone local that's willing to do some tuning for me, on a regional W-body board. Seems the most recent software release from DHP doesn't limit what vehicles it can be used on, he says. Thinking maybe next spring will try to get together and try to sort it out.

I should also Seafoam thru the brake vac hose before winter arrives, who knows if it's ever been done before.

Dave, this just appears more abnormal to me the more I read. Did you ever scan with the stock SC pulley? 8 deg KR should not be happening, no way, no how with your mod level, especially in cooler weather. Either it's not real, or something's wrong.

We need to find out if there's a problem somewhere that's been overlooked. Can you scan for MAP? If we knew how much boost you're pushing when you get that KR, it might be easier to tell what's happening.

Just for the heck of it, I'd go fill up with some premium from a gas station in another town. I know you said you used the same station every time. I doubt that's not the problem, but you never can be too sure.

Fuel filter been changed lately? I would like to see how your LTFTs look during a drive.

Aaron, I had a blip of KR with the stock pulley that was under 1deg. New AC fuel filter back in May or June. K&N is pretty clean. New AL605's in the spring. Very few stations here carry 92 even, most are 91. I can drive across the river to Moorhead and run some 100 unleaded too. My tank is around 1/4 right now, and I have some running around to do today. Later on I'll go over and shoot for a 50/50 mix of my current 92 + the 100.

I'm going to try to log a scan tomororw with KR, MAP, IAT, LTFT, MAFF, TPS, etc. I believe I can do 10 parameters at a time. What other specific ones should I get? I still need to get my LS1M software installed on the new Dell though. Had to buy a $36 USB to S/P adapter for the PDA hotsync cradle... I agree completely, there's no way I should be seeing this level of KR, if any. I do think it is real, as I see it right away on hard acceleration, not with tranny shifts.

1998 Riv wrote:

I do think it is real, as I see it right away on hard acceleration, not with tranny shifts.

Does it just spike and disappear or does it go up as you keep accelerating?

maybe spiking due to your boost bypass valve being too "low" (flash kr)

it appears to increase as I increase throttle, rather than simply spiking. Hard to be certain though, as I'm only watching it in gauge mode while driving. I will try to log a good scan probably tomorrow. Right now I'm on the way out the door to do a Seafoam treatment.

Jason wrote:

maybe spiking due to your boost bypass valve being too "low" (flash kr)

I'm not familiar with this issue, can you elaborate?

some people have experienced flash KR when doing the free boost bypass mod (where you unbolt the 2 bolts and lower the cylinder to the max).

Jason wrote:

some people have experienced flash KR when doing the free boost bypass mod (where you unbolt the 2 bolts and lower the cylinder to the max).

Yeah, I haven't seen any good reasons to do that mod.

The local guy with a DHP has offered to load me a DHP file tomorrow if we can get together at the Street Legal races. Don't know which file, aren't there like 1.0, 1.5, etc? Any reasons I should NOT let him load this???? At least I'd get the trans shift changes, 180 fan settings...

if he has a DHP and can help you it's version 1.5, which isn't really anything spectacular. It has some nice transmission features and torque abuse stuff, but it really isn't a performance bin. I see no reason not to upload version 1.5, but don't expect much KR reduction or performance gains.

Also, don't we need to make some other changes with our Rivs in order for the transmission changes to actually function? DHP site says they only work with vehicles with the Perf Shift button. I think Aaron had to modify something else for this, or maybe I got this info from Gary Hollands' tuning site....

I wouldnt' be expecting a lot from the DHP file, but it should help with cooling, I have a 180, but no fan turn-on changes made. Also I believe it richens up the fueling? Can't hurt either, I suspect I may be running lean. We'll see, not even sure we'll get together at the races. Will be TONS of cars there today, in conjunction with yesterday's car show.

does the guy have a riviera 1.5 bin?

So far all I know is he has the newest software which allows tuning on all the L67 cars. I need to get into the details with him IF we can get together at the races. His comment yesterday on another board was that he could load a DHP file for me, that's all.

The DHP 1.5 BIN is programmed to work with a Riviera PCM, but the values are not specific to us. I think they are generic values used with every 1.5 BIN they send out. I'm not sure, but that's what I think. I saw only slight differences installing the 1.5 BIN. To get true changes in performance, you have to modify the shift tables, and the MAF tables for fueling. There are other methods for tuning as well.

I have the shifts programmed with Perf Shift on all the time. You don't need a Perf Shift button if you just copy the values over the normal tables, but you can't turn it off. Personally, I wouldn't want to. If you want these values, I can send them, and you could enter manually, or am more than happy to send a BIN file already set.

But for the Kr problem, you should really have the tuner to yourself, imo. It's very unlikely you'll resolve a fueling issue in one shot. Best results come when you tune, then scan, then tune, then scan... I've probably tuned my fueling 20-30 times so far. Every little mod, change in temperature, or octane can make the need to optimize.

When you scan, try to capture the following parameters:
1) IAT
2) Throttle %
3) RPM
4) Timing ADV
5) A/F Ratio
6) LTFT
7) 02(sensor 1)
8) MAFF
9) MAP
10) KR

Also, if you can log: MPH, BAR Pressure, Coolant Temp, Gear... it's nice to have, but not required.

Didn't get together today at all. I had decided not to have this guy do anything anyway. Next spring I may look into a buying a PCM for the Riv.

Aaron, I agree totally about doing the tuning myself, but that just ain't gonna happen. There's a world of difference between being a 20-something single guy, and being a 40-something guy raising a young family. I just don't have the time and energy to devote to that. I need to do some serious searching for someone who can work on this for me, like Gary Holland. He's too dang far away though, as is Intense.

BTW, no chance to log any scans this afternoon. After I got home from racing the 68, wife had to devote several hours to work, so I had kids to take care of. They didn't stay at the track very long, turned out the real race cars were just too loud for my 2yr old's ears... On the bright side, I got a new PB ET and 60' with the GS. Turned a 15.38 with a 2.18 60'. I think it's time to put a street/strip cam in it, but what it really needs is some decent gearing. The 2.56 rear just doesn't cut it at the track.

(only 10 parameters at a time with the LS1M)

AA wrote:

........ or am more than happy to send a BIN file already set.......

That would be too freaking cool... then to find someone to load it. Turns out the guy I was going to see today lives about 80 miles away.

As for the KR issue, I also need to double check to make sure the pulley I received was in fact a 3.6. Hadn't considered that could have been a mistake by PFYC also. Worth checking though.

Understand about tuning. It's not for everyone. It's not for me either as I'm finding out, yet I still try with moderate success. I will find an older BIN that has all the goods without too many fueling changes.

Good idea to measure the SC pulley!

Yeah, I would imagine your current fueling setup would be a bit much for my mods.

I mention the pulley size because I remember a guy on 3800Pro.com had KR issues that he shouldn't have had, checked his pulley and it was like 1-2 sizes smaller than he ordered. Now I would assume that 3.6 would not be measured at the outside diameter of the pulley. Hard to measure diameter at the grooves, maybe I'll ask PFYC what the outside diameter is for their 3.6 pulleys.

Aaron, did you originally buy a Riv specific PCM from Intense? Or did you go straight to tuning your stock PCM? I thought someone got a Riv PCM from them. I don't see our application on the website.

Measure O.D. on the pulley for correct size.

I never dealt with INTENSE for PCM tuning. I still have my OEM unit, reprogrammed with PowrTuner. Didn't much like the idea of physically swapping out the chip anyway. It's buried in the dash, so it would seem a little more difficult than a GS or GTP that is under the hood.

Our application falls under "custom" from INTENSE, which is $250 last I checked. Doesn't make much sense when you can have unlimited tunes for $390. Plus, the support of DHP forums is invaluable, imo.

1998 Riv wrote:

I mention the pulley size because I remember a guy on 3800Pro.com had KR issues that he shouldn't have had, checked his pulley and it was like 1-2 sizes smaller than he ordered. Now I would assume that 3.6 would not be measured at the outside diameter of the pulley. Hard to measure diameter at the grooves, maybe I'll ask PFYC what the outside diameter is for their 3.6 pulleys.

That happend to someone on here too. Got a 3.25" pulley instead of a 3.4" I believe.

AA wrote:

Measure O.D. on the pulley for correct size.

I never dealt with INTENSE for PCM tuning. I still have my OEM unit, reprogrammed with PowrTuner. Didn't much like the idea of physically swapping out the chip anyway. It's buried in the dash, so it would seem a little more difficult than a GS or GTP that is under the hood.

Our application falls under "custom" from INTENSE, which is $250 last I checked. Doesn't make much sense when you can have unlimited tunes for $390. Plus, the support of DHP forums is invaluable, imo.

Very good points on the PCM vs a PT. Didn't realize custom was that expensive! I also didn't know ours was buried in the dash, certainly something to consider. I was going to have Ed Morad get me a 98 Riv PCM, guess I'll have him send $$ instead for my OEM cat. Ok, time to go measure the pulley...

Ok... the PFYC 3.6 pulley measures a hair OVER 3.75" OD. I'll contact them and find out what I need to measure to confirm the size they sent me.

I did log a couple scans at noon today. Will load them on Scan Depot tonight and post here. Looked at the log file on my Palm though. I did 0-90 runs and saw a max KR of 5.0. This logged at 43.5mph, 93% TPS, and 3273 rpm. KR started at 21mph at .78, and steadily rose to the 5.0 at 43mph. From there is steadily dropped down to 2.5 KR at 60mph, 100% tps, 3893 rpm. From 60 to 90 mph, it came back up to around 4deg and was in that range mostly.

Sorry if that info is garbled, I can't load the scan here at work. So, no sign of the 8deg I saw a few days ago, but still high at 5.0. All I've done since is a top end clean with Seafoam yesterday. That certainly could have helped a bit, but I did not get a HUGE smoke cloud, so probably didn't have a real filthy engine.

Ambient was 70, IAT probably around 80. ECT in the 190 area. Boost topped out at 9.12 near the end of the run.

As much as you've been running WOT, I doubt it was that dirty. Still, doesn't hurt to try.

Why not change the plugs to Autolite 104s? You're due for a plug change anyhow after the Sea Foam job. Gap to .058"

Is LTFT locking in at zero when you go WOT? Did you record MAFF, A/F and O2? If you can list those values, I can do a rough custom fuel tune to the BIN before I send it to you.