Manual Boost Controller Recommendations?

[Tom]

Wow just read that chip tuning thread. Wild & impressive

Post #12 - it appears that the tables for the modified chips have LESS fuel in the 3000-5000 rpm range than the stock chips. Did you mix the tables up?

If the cycling valve has been removed and different boost control is used (MBC etc), the stock-chipped KLR overboost protection no longer protects anything, correct?

Post #55: no cat cars didn't come with an O2 sensor? Is the only function of the O2 sensor emissions-related? I thought the regulation of the AFR in closed-loop is helpful for reliability, fuel economy, perhaps driveability (accompanying for wear over time). Is there any advantage other than emissions for keeping the O2 sensor plugged in?

In the most recent posts, discussion revolves around return-to-idle ; return-to-throttle. I can tell I need to re-solder my boards as the car will start jerking / bunny-hopping more often, esp at the low-rpm off-throttle ; on-throttle and "creeping" in traffic speeds. After a re-solder, all this diappears

More than ever I wish I kept the cycling valve. I am very happy with stock boost and I only got rid of it because it was showing bubbles (leaking) at the electrical connections when testing for vacuum leaks using pressurized air

New ones were quite pricey vs MBC and in my limited knowledge coupled with all the boost hype, I ditched it, only to try and dial in similar max boost as stock; I got rid of a sophisticated electronic control for a cheap plastic knob

Now that I understand things more, I kinda want it back, but I've since removed all the mounting and they are NLA anyway.

I run the A-Tune chip with both a ball-and-spring on the wastegate feed line (a la Lindsay Boost Enhancer) AND the MBC--one helps boost build sooner and the other protects for overboost (I understand the ball & springs are not as reliable in overboost protection)

But I guess I have lost all the subtleties of the KLR and its various fine-tuned controls over airflow...

Stock Man Dan

Thanks. Post #12 is accurate. Those are two common aftermarket chips. I imagine the factory added lots of fuel in the max-torque range for safety and the tuners pulled a little out for responsiveness in that range.

As a practical matter, using an aftermarket boost controller negates the KLR protections -- I 'think' it may still generate blink codes inside, but with no effect on anything. @johnb would be best to confirm that the blink codes are still there.

There were so many variations around the globe, I hesitate to say there was never a car with O2 sensor and no cat, but generally they went together. Although the sensor may have been added to preserve the cat, to your point, the sensor and closed-loop system have all the benefits you list. Absolutely beneficial with or without the cat, in my opinion.

You shouldn't need to routinely resolder the DME. If you continue to get cracks, I'd suck out as much of the old solder as possible in case it's compromised and be sure to use a good 63/27 lead solder like Kester.

Re the cycling valve -- the longer I own this car, the more I see the wisdom in the stock parts. I do love my Profec B though... It controls max boost, but also spool speed so you can have it hit as hard or soft as you want.

[danmartinic]

Could be I am using wrong solder.. I have zero knowledge here and I just used something I bought at an audio/video repair place long time ago

It says "Rosin Core Solder" on it

Last time lasted 7 years of DD so that's not too bad

I am surprised there is little vibration isolation in that mount (nevermind passenger foot stomping lol)

[johnb]

Wow just read that chip tuning thread. Wild & impressive

Post #12 - it appears that the tables for the modified chips have LESS fuel in the 3000-5000 rpm range than the stock chips. Did you mix the tables up?

If the cycling valve has been removed and different boost control is used (MBC etc), the stock-chipped KLR overboost protection no longer protects anything, correct?

Post #55: no cat cars didn't come with an O2 sensor? Is the only function of the O2 sensor emissions-related? I thought the regulation of the AFR in closed-loop is helpful for reliability, fuel economy, perhaps driveability (accompanying for wear over time). Is there any advantage other than emissions for keeping the O2 sensor plugged in?

In the most recent posts, discussion revolves around return-to-idle ; return-to-throttle. I can tell I need to re-solder my boards as the car will start jerking / bunny-hopping more often, esp at the low-rpm off-throttle ; on-throttle and "creeping" in traffic speeds. After a re-solder, all this diappears

More than ever I wish I kept the cycling valve. I am very happy with stock boost and I only got rid of it because it was showing bubbles (leaking) at the electrical connections when testing for vacuum leaks using pressurized air

New ones were quite pricey vs MBC and in my limited knowledge coupled with all the boost hype, I ditched it, only to try and dial in similar max boost as stock; I got rid of a sophisticated electronic control for a cheap plastic knob

Now that I understand things more, I kinda want it back, but I've since removed all the mounting and they are NLA anyway.

I run the A-Tune chip with both a ball-and-spring on the wastegate feed line (a la Lindsay Boost Enhancer) AND the MBC--one helps boost build sooner and the other protects for overboost (I understand the ball & springs are not as reliable in overboost protection)

But I guess I have lost all the subtleties of the KLR and its various fine-tuned controls over airflow...

Stock Man Dan

Thanks. Post #12 is accurate. Those are two common aftermarket chips. I imagine the factory added lots of fuel in the max-torque range for safety and the tuners pulled a little out for responsiveness in that range.

As a practical matter, using an aftermarket boost controller negates the KLR protections -- I 'think' it may still generate blink codes inside, but with no effect on anything. @johnb would be best to confirm that the blink codes are still there.

There were so many variations around the globe, I hesitate to say there was never a car with O2 sensor and no cat, but generally they went together. Although the sensor may have been added to preserve the cat, to your point, the sensor and closed-loop system have all the benefits you list. Absolutely beneficial with or without the cat, in my opinion.

You shouldn't need to routinely resolder the DME. If you continue to get cracks, I'd suck out as much of the old solder as possible in case it's compromised and be sure to use a good 63/27 lead solder like Kester.

Re the cycling valve -- the longer I own this car, the more I see the wisdom in the stock parts. I do love my Profec B though... It controls max boost, but also spool speed so you can have it hit as hard or soft as you want.

Correct on the KLR - it will still provide most if its knock protection (via timing), which is by far the most important thing. It's pretty easy to get the car to run without the KLR, but if anyone thinks they should do this because they are not using it for boost control any more, that would be a big mistake!

It will still monitor conditions for blink codes. I actually don't think it has any way to detect the CV valve being disconnected, I can't remember right now. In theory you could get high/low boost blink codes if you have a different boost curve from the one the KLR tries to track, but in practice it's not likely, because the tolerance is very high.

I would say the biggest risk to having non-stock boost control is that if the KLR detects a problem with the knock sensor system, it'll trigger a blink code but you won't know. On a stock car you'll know because you'll have very little boost. Modified cars should have a light for blink codes in my opinion.

I do think the O2 sensor always went hand-in-hand with the cat. I'm not sure the O2 sensor helps with anything else. If you have problems with vacuum leaks or whatever, the O2 will mask them in steady state, but I'm not sure it would be fast enough to react to transient conditions. I'd rather know about the problem and fix it. It's not like newer cars that have trim tables - those trim tables change the baseline fueling so they have their affect instantly, and so they really do compensate for leaks and such.

It's pretty easy to activate the non-O2 maps on a US car if anyone wants to see the difference. You just connect a 1.8k resistor across the altimeter connector IIRC. The O2 part throttle map is rich, and is pulled back to 14.7:1 by the feedback loop.

The non-O2 PT map just targets 14.7:1 directly. Idle and WOT are the same. Also the non-O2 PT code path has acceleration enrichment at all temps. The O2 setup only has it when cold. Once the O2 sensor kicks in, any accel enrichment would be fighting against the closed loop. They all get some enrichment from the overshoot of the mechanical AFM anyway. I don't know if there's a difference in driveability. My car has the O2, currently no cat, but it's also not running quite right so my tests are not much use.

Also @danmartinic prepare to kick yourself...the cycling valves all leak a little from the connector, even new out of the box!

[danmartinic]

Modified cars should have a light for blink codes in my opinion.


Also @danmartinic prepare to kick yourself...the cycling valves all leak a little from the connector, even new out of the box!

Long ago, I made a blink code light: a 12v LED with ends to fit the diagnostic port. Never got it to light up no matter what I did. What am I missing?

They all leak like that??

I was just into my early thirties.. excited to buy this car.. living on Rennlist threads... and of course I'm gonna make it even better thanks to exciting new technologies like plastic psi regulators and silicone tubing

[johnb]

Modified cars should have a light for blink codes in my opinion.


Also @danmartinic prepare to kick yourself...the cycling valves all leak a little from the connector, even new out of the box!

Long ago, I made a blink code light: a 12v LED with ends to fit the diagnostic port. Never got it to light up no matter what I did. What am I missing?

They all leak like that??

I was just into my early thirties.. excited to buy this car.. living on Rennlist threads... and of course I'm gonna make it even better thanks to exciting new technologies like plastic psi regulators and silicone tubing

You can induce a blink code easily by unplugging the TPS. You should see the blink codes below 1500rpm. You might have to exceed 1500rpm once to get them to trigger, I can't remember. But other than that there shouldn't be anything to it.