OK - need some assistance here people. I've recently replaced the fuel system in the 242 (new pumps all around - thanks Dale and Jim for the pumps and bung tool respectively) as well as new fuel filter (Bosch this time). Running a 740T in tank pump into a new K-Jet pump (still have the accumulator). The turbo is the TDO4HL-15G. Stock wastegate and manual boost controller (the ball check valve type). Exhaust is 2.5".

Here's what it does now - start up and other silly things are gone with the new pumps. That's been nice. I'm still getting some weird behaviour in 2nd gear that I just don't understand. I was out scouting locations for field work this morning running around some back roads and decided to do some hard pulls to see what was up. From a dead start (all systems warmed up from 60 km drive) it will pull hard in first gear to the redline. Then shift into second and it falls flat. I can't describe it, but it seems to loose power. Then in third, we're back in the game again and it's not a problem to rev it out to redline. Redline in second is weird. I react to it by shifting. It sort of seems to go lean on me.

I don't know what boost spike would feel like.

Could this be wastegate related (like it's not building boost)? I can't watch the gauges/road at the same time. It's probably time for a dyno session.

Thoughts.

What style of MBC do you have? Pull it out and see if that fixes the response. I don't trust those things to properly vent the wastegate when you shift, especially when they get cruddy.

It's a Yoshifab one simple bleed with a ball/spring arrangement inside. I'll pull it today and test it. I'm lining up for a dyno pull in the near future to see if the AFR's are OK.

Removed the MBC - in second gear, I still got 11 psi. So something's not right. Talked with Matt and we figure I'm getting boost creep at higher RPM (again, 1/2 shift at 6500 RPM). I wonder if the wastegate actuator is adjusted properly. I'll have a look this week and see if I can figure it out. Not a lot of really good information on how to do things like adjusting that WGA. If it's leaking a little, then I may not be getting it to open up all the way, causing the boost creep. Either way - somethings not right. I do have a spare 15G to fix up if this isn't fixed soon. I don't really want more turbo for this car so maybe a stock rebuild with larger wastegate is what the doctor ordered.

So wait, you're hitting 11psi but it's falling flat on its face? Like over boost and fuel cut or just no power like the intake is getting sucked shut? The sucking intake doesn't make sense if the other gears are fine though. A boost spike causing fuel cut would likely be worse in third gear as well so that's odd.
I forget are you LH 2.2 or 2.4?

It was falling flat before I removed the MBC - it still doesn't like to pull as hard in second as it does in first or third. This could be related to a wastegate that is misbehaving. It has fuel cut on me for sure. It does seem worse if you hit redline in 1st. Can the intake get sucked shut (is the cobra collapsing? I'm on 2.4. Still have to check to make sure my wastegate is adjusted properly...though I have to be honest and say that I've never adjusted a wastegate and don't know what I'm looking to do.

Just hook up the waste gate to a pressure source, bike pump or shop air regulated down to 5-10psi and see what pressure the actuator starts to move.
Intake could be sucking shut if you're using the original hose system. Stick a piece of appropriate pvc in there to rule that out.
Still the fact that second gear is worst is odd. Hitting red line will obviously give you problems- ignition will cut out as its designed!

Here's the wastegate tester I put together.



I then managed to get the wastegate disconnected which is no mean feat given it's location on this car. Can't see anything. Then after watching the IPD how to adjust your wastegate video on Youtube, I set about adjusting it. It had a ton of preload (like 4 or 5 turns) it''s sort of hard to know how many because I was working completely blind and trying to count while adjusting it was slightly pointless. It was more than a shaft's length out of position and had to be stretched a lot to get it on the wastegate arm. IPD claims this will cause spikes.

So I adjusted it to where it will basically just fall onto the shaft, put it together and tested it and it starts to open at much lower psi (like a few pounds only) and is fully open by what looked like 6 - 7 lbs on my gauge. I put it all back together and went for a drive.

I'm not 100 % sure it's fixed, but boost is now at a rock solid 5 psi and it didn't drift through several 2nd gear pulls. It's not what it was at 10 psi...but it was more linear and it was the same every time - even when I bounced it off the rev limiter. I also was reasonably convinced that it was more linear coming on boost. It hit pretty hard before and several of the instructors at the autocross noted the "exponential" power delivery of the previous set up.

So I'll have to put the MBC back on (this is also the advice on 15G's from TBrix...adjust to 5 psi - install MBC and turn up the wick). We'll see if that has the problem licked.


I'm off to the dyno next Thursday and will report back with numbers.

Well, we've learned a few things. I reinstalled the MBC and without changing anything it was only giving me 7 psi...odd, with the preload this was 12 psi. One thing that I did do was to change the size of the lines supplying the wastegate. They are an in between sort of size and I had gone with the larger size and lots of clamps. So I ditched that stuff and replaced it with hose that fits the MBC that I could jam onto the compressor and wastegate. A few little spring clips (it's only a few psi...it's not going anywhere) and I took it out for some tuning. Initially it felt lean under boost again as I was dealing in the wastegate to the desired pressure. After sitting in a few regions of the map off WOT (which is different in LH 2.4 as it's open loop) to help it figure things out fuel wise and it started running pretty well. I'm not convinced we're fixed, but boost pressure is solved. That's fine. The car needs to learn more so I've got to show it some boost for the next few days and LH will re-map things for me. Hope this is case closed - I race on Sunday and I need to return to the 122.

Noice

I'm reposting this from TBrix...

So I just got back from the dyno...I've been having tune issues and just couldn't track it down without gathering actual data. This is a reasonably long story, so I hope you can stay with this winding tale. First, the details.

B230FT (H-beams, squirters, you get the idea). 9:1 SCR.
530 Head (larger valves, stiffer valve springs, 3 angle valve job, ported)
90+ exhaust (also ported and ceramic coated)
Mitsu TDO4HL-15G - (also ported and ceramic coated)
Stock 740 Intercooler.
Bosch 42lb (440cc) "Green Giant" High-Impedance Injector (Bosch 0 280 155 968).
Ceramic coated stock intake manifold.
LH 2.4 running TLOA Chips (Gold ICU also chipped).
New O2 sensor, new CPS, New pretty much everything.
Manual boost controller from YoshiFab - set so that we're all in at 10 psi. Wastegate without the leak is 5 psi and recently adjusted properly.
New K-Jet main pump (new)
740T intank fuel pump (new).

So as I've been auto crossing, I've noticed (as has everyone around me) that from time to time the car lacks power, it snaps and pops like it's on the rev limiter (at like 4.5K rpm) seems rich as heck. Then, for whatever reason it would come alive and behave brilliantly. Lots of power all the way to the rev limiter. You just don't know which car you're going to be driving.

I adjusted the wastegate and changed out the fuel pumps to cure some other issues, but the tune problem hadn't gone away. It was "better" but not "right" and certainly not consistent. We only have one dyno in town, and it's booked pretty heavily...so I've been waiting to get on the thing to find out what the heck's going on.

Well, today was that day - WHOA, we got trouble people. So the first 5 pulls were aborted due to it behaving very badly. No point in rev'ing it over 4.5K rpm...even the office lady came out to see if anyone was actually getting shot. These pulls were in either 4th or 3rd gear.

They look like this (warning - these are hard to look at they are so ugly).



Don't worry about that little return dangle - it's meaningless. AFR's are PIG RICH...like in the 9's rich. We do this 5 times. Same results. We try to ease it up to 5K rpm and then roll onto redline. No dice. Same junk. Look at the AFR's just going FAT.



Then we tried to just see if it would behave in 2nd gear...and mg::omg::omg: we get this pull.



WTF is going on here. Here's the comparison.



No one's complaining about the pink line (that's the second gear pull) - making 208 WHP with 208 lb/ft torque (lower than the nonsense pulls).

Thing is, we can't get it to do that pull unless it's in the lower gears. So why? Also note the AFR's are ROCK SOLID. The AFR's were measured in the tail pipe, so are not quite right.

Seriously...has anyone seen this? What am I changing NOW? At first we thought that the injectors were just too big? Why does it work right sometimes and not others? Is LH 2.4 done?

Just for fun - here's the vid.
[url="https://youtu.be/2S1zQzhOldo"]https://youtu.be/2S1zQzhOldo[/url]

You have non-chipped ECU/ICUs, right? I had a TLOA 2.2 evu and hated it.

To me it looks like you're hitting the knock sensor and then started enriching the mix. With those monster injectors it just goes overboard.

That intercooler is just crap, BTW. It'll heat soak in an instant, and in 3rd & 4th gear it has lots of time to misbehave. When the car is moving down the road it's probably keeping cool enough to run better.

You've got a combination that none of us have tried, I'd try running stock computers first but that might bring other problems. Maybe stock injectors (they'll handle 200hp and a bit more) and see what that does. Maybe deal with that IC because you really do want to before long.

You'll get it.

The funny part is the 2nd gear pull was the 6th pull. So why is it gear related? The only difference is how fast it moves the dyno (it spools the dyno faster). Got the knock thing and fuel dump is for sure. I could upgrade the IC next year...it wasn't that hot...and we could touch the IC pipes/hoses without issue.

I could look for a new set of computers. I don't have a spare set. Easy to find. Easy to change. Don't feel like running it in the last race like this. I've run some estimates for injector sizing and I'm not that far off with these things at 42 lbs/hr...could be a little smaller, but some calculators say 40 lbs/hr with 90% duty cycle at 250 crank HP (which is what I'm at...give or take).

If it pulled like the pink line in all gears, we'd be done. Athal was thinking boost spike.

I was thinking that in 2nd it would accelerate the dyno fast enough that you wouldn't overheat whatever was getting overheated. And math be damned, Athal made a little over 200 on the dyno on LH2.2 and pretty stock injectors, I don't recall what they were, might have been browntop 35 lb/hr. I made 185 on stock 29 lb/hr with a teeny tiny turbo and a completely stock motor and I wasn't running lean, so I'm pretty sure you don't need 42s for 208.

The thing is, it's not that fine a line between running perfectly and running like crap, normally. These things are pretty robust and not that sensitive to a few knock events or degrees C.

One thing that just occurred to me: your vehicle speed sensor. Is it getting some noise in that circuit, or is the signal from the speedo cable thingie somehow not quite what the ECU wants?

Edit - I hadn't taken a close look at the overlayed graphs. Athal's got a point: your torque curves are miles apart. Wastegate for sure. I assumed you were watching the boost gauge while the runs were happening, but no?

Without being able to log boost it was hard...my first thought went to injectors as the AFR's went rich and we hadn't seen a good pull. Then when we did get a good pull (still a hair rich) I was pretty confused (as was the dyno guy). Then we thought heat - but it really wasn't heat soaked. Then we tried rolling past the RPM threshold before getting on it (so a pull from 5K to 6.5K) and it did the same thing. Then we tried a foot down, but not WOT tug and no difference. So that's leading me away from fuel and back to wastegate. The only other thing I changed was the recirculating valve spring and diaphragm. It's just the upgraded IPD stuff. I don't see that being an issue.

Gotta keep pealing back the tune issue. Frick.