The LNF and the boost controller.

[mkriebs]

Anyone ever ran the combination?

I am running one i made, and its just being a whore to tune. One second its boosting much farther than I want it to, the next second its boosting like I want it to (24 psi), then the next second its running 21 psi. I don't get it.

I feel like the computer is learning down the boost controller. I don't know why it would do this, or is it not doing it? I have overboost and underboost turned off, have my DAL's dialed in decently, not where I absolutely want it, but its still a work in progress.

Also, the VE airflow spikes to like 67#'s. Why is this? Is this my turbo overspooling?

I'm stumped. I have it back to my latest tune right now cuz I am too much of a chicken to blow something up, lol.

Well then... I would add a tune, but for some reason its not uploading to the site...

[Iam Broke]

VE is calculated by the pressure drop across the throttle body. If the ECU is forcing the closing of the throttle plate, it'll increase the differential pressure and the VE airflow. What is the MAF and throttle position doing when this happens?

Just a thought, I never tried a manual boost controller here.

[mkriebs]

The TPS is normal, and the MAF is normal. I am stumped. It seems to happen when the MAP tops out... but not every time. The MAF and VE pressures when its not spiking are phenomenal. IDK...

[Iam Broke]

Well the VE uses the 2 MAP sensors to determine the differential across the throttle plate one in the cold side CP (high pressure side) and one in the manifold (low pressure side) so if one of them is saturating on a spike, I suppose it would cause a very high differential thus showing a large flow. Might be getting close to failing from overpressure spikes.

In Instrumentation we use an orifice plate or another primary element to develop a delta P to calculate flow. Differential pressure increases at the square of flow and all that rot. They use the throttle body restriction. If either the high or low pressure side goes flaky, there ya go...

[mkriebs]

See it doesn't happen until the MAP tops out at 255. So... that makes sense. Since its seeing one side get a ton of pressure, that it technically cannot read. Hmmmm... wonder if this is something I should worry about...

[Iam Broke]

Mine barely taps 255 kPa when I go WOT so I don't see the saturation you do. With all your boost one may be topping out (cold side CP) and the other isn't, showing excessive flow. If it dies altogether, my money is on the cold side CP MAP sensor.

[mkriebs]

Gotcha.

So... how red should my turbo get?

[Gimpster]

Not uncommon on any of my turbo cars for the manifold, turbo and o2 housing to be a nice cherry red after a hard pull.

Can you clarify if you're running the MBC alone, or using it in conjunction with the stock boost control solenoid? Curious because on other cars I've seen people do that sort of schtuff.

I have an ooooold GReddy Profec B Spec 1 I'd been toying with putting on my car lately.

[BackyardTurbo_FTW]

^I have a E01 in the attic and Ive been in the same debate LOL!

[Iam Broke]

Gotcha.

So... how red should my turbo get?

You know, I've wondered about that myself. Steel starts to emit light above 1200*f from what I remember at the mills. I suspect our manis are cast but what ever...

When I see cat est. temps of 1850f at 125 mph I wonder how red that sucker is glowing.

I digress but I had an old 84 Fiero I was fixing up for my daughter and I had a dist. oil leak. Had to pull the EGR valve off to pull the dist. to replace the seal. WHen I put it back together I had the EGR cocked on the mani and a bad vacuum leak. That sucker started up, ran up to 4k rpm. I went back to look at the engine to see what's what and the mani was bright cherry red, next to the firewall, wire looms smokin' HOLY SH!T thought I was going to burn the house down by the time I got it shut off. That mani was folded up steel sheet.

They were known to blow up from running out of oil, not catchin' on fire though. They had a 3 qt oil pan on the iron duke before the recall. Get a qt low and BOOM!, there goes a rod. I had a front plate that said Fire Hazard.

[BackyardTurbo_FTW]

1850? Holy crap! On a full 4th pull my max is 1650.

[Iam Broke]

I was running .90 Lambda the day I saw that on the racing fuel blend. No KR at 17*

I richened it up to .87 last night to see how it does. No sense to burning everything up.

2 ranges colder on the plugs for a month now and I pulled one this morning for inspection, looked perfect.

[mkriebs]

Not uncommon on any of my turbo cars for the manifold, turbo and o2 housing to be a nice cherry red after a hard pull.

Can you clarify if you're running the MBC alone, or using it in conjunction with the stock boost control solenoid? Curious because on other cars I've seen people do that sort of schtuff.

I have an ooooold GReddy Profec B Spec 1 I'd been toying with putting on my car lately.

I am running it on the stock boost control solenoid. Just using the MBC to control the pressure going to the wastegate. This way, I can tune the DAL's in HPT to get what I want. Just, if you do it, start out with very low DAL's and work up from there. Lol. Right now I am running a peak of 25, and it slowly works its way down to 21-22 at redline. It pulls very hard, but I am definitely not going to run this on the street much.

[BackyardTurbo_FTW]

I did the .030 welding tip as mentioned by BTF in another thread and WOW....Getting 25-26 spike and holding 23 to redline, NO dip in boost AT ALL!!! Highly recommend it, will cost you $10 but getting it on there was a real BITCH!!!

[Iam Broke]

Too bad we can't access the tables we need. It'd be a lot easier.

[BackyardTurbo_FTW]

This is a mechanical version of doing the same thing. Also very similar to what a manual boost controller does

[Jaxon]

Link to the welding tip?

[BackyardTurbo_FTW]

Its the limp limp be gone thread.

[Gimpster]

Yah, I've started to think the highest request on the list (maybe even before fuel) should be full control over the BCS duty cycle.

Wifes workin' tomorrow, guess I have a little project to do Sure hope this thing still works because its been off my other car for like 4 yrs. I'm hoping since its an EBC it can keep that boost up till redline, and if not I'll shove a couple washers under the WG and see if that helps. I think its way easier to jack the car up when fiddling with the WG. I ran a homem ade MBC on this car for quite awhile until buying HPT.

The ole welding tip trick is kinda neat, lot of RX7 guys do that.

[mkriebs]

AHA! Thats the trick I was looking for! I asked rick what it was, because I couldn't find it again, but he never got back to me about it. Did you adjust your DAL's at all? Might be something for me to try. the MBC I made is not consistent enough. One second it will boost 21, the next it will overboost to 30. I don't like it. It happened tonight and I heard a pop, now whenever I boost over 10psi I get crazy knock. Gonna have to investigate further tomorrow.


So, just a tip like this?