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Discussion Starter · #1 · (Edited)
My Seq TT BPU tuning adventure

My current mods are in sig. Right now I am just data logging and gathering information about my set up before tuning the AFR with my EMB. Being that I just passed smog with my RT cat + second cat in place and I personally dont track the car (also saw some penguins dying in some Antarctica documentary), I have decided to keep them on and not hassle with midpipe (oh, and save the world). That being said, my set up isnt technically BPU. My goal in this endeavor is to identify any weak links, and get the proper AFR for maximum fun.

With California 91 octane, I am shooting for 15.5-16 psi max here. I am first trying to see if there are any issues with my sequential system and wastegate weakness

STREET LOG link

Based on the logs, I see ~12.3 psi before transition and dropping off to 9 psi during transition then hitting ~15 psi. Should I be concerned about the drop off in boost? I will do another mityvac test to make sure my sequential system is not leaking but just wondering if others have an idea where the drop off can be coming from.

Secondly, I will also try to log to higher RPMs to see how my boost holds up and whether I need to put the wastegate spring mod back on.

Any feedback would be great. Thanks

Tsung
 

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That drop in boost in transition is normal/expected. Basically some of the exhaust energy is bled off to pre-spool the 2nd turbo, and that's what causes the drop. You can reduce or eliminate that drop at the expense of additional wear and tear on #2, so not really recommended..
 

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Discussion Starter · #3 · (Edited)
Uploaded new picture logs after putting on my wastegate springs. I now require less duty% on the ebc to get to the same peak boost. What I notice on the 2 logs that I rev to 5k+ rpm, the boost peaks at ~4300 RPM to 15.3/15.9 psi then immediately fall back to around mid 14s. I assume I need to play with the ebc gain feature that kicks in 1.5 seconds after active boost. OR I need to take off my spring mod and reduce my boost spike....

A very weird phenomenon happened on one of my logs where I put it in manu OD off in 3rd and floored it in low RPM: The transition seem to happen at ~3200 RPM rather than the usual 3800-4k rpm. Any way to explain this one?

lastly, I am pretty set on my pre transition boost to be where is it now (12.5-13psi). Looking at the AFR in open loop in pre transition, at 12.5-12.9 psi, should i be looking to lower the AFR to ~12.0 instead?
 

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Discussion Starter · #4 ·
After much inconsistency with peak boost using wastegate spring mod, I had taken it off and reverted back to using hallman mbc. Now I understand my peak boost characteristics to be ~13 psi pretransition. Post transition 14.4 psi on 2nd gear, 15.8 psi on 3rd gear.
 

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Discussion Starter · #5 ·
Having understood my boost characteristics in MBC, I have moved back to electronic boost controller from innovate SCG-1. due to the 4psi dip I get in transition and also multiple factors that cause boost controller to be out of duty cycle during transition, I have picked 5.5 psi as the scg-1 spring pressure. At 40-48% duty cycle yields me my target boost of 13.5 2nd gear 15ish psi 3rd gear depending on weather conditions.

After much research into maximizing BPU on SF and talking to members, the biggest limiting factor at BPU is the pump gas at 91 oct. being OBD1, it's impossible to know about timing and knock. Was looking into meth/water injection systems but ultimately need to be able to log timing and knock.

took me some time but I have 2 threads here that will point those looking for obd1 datalogging in the right direction.
http://www.supraforums.com/forum/showthread.php?962402-obd1-scanner-for-timing-and-knock
http://www.supraforums.com/forum/sh...s-from-a-NON-OBD2-ECU&p=12371914#post12371914

Being able to log timing in low framerate, I saw my third gear pull at 15 psi peak yielded 13 degree timing. Very far from the 23 degree that is supposedly full timing. Also see my AFR to be around low 10s. Next step is to look into meth injection and see if I can gain timing back.
 

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If I were you id buy an obd2 ecu and actually tune the car....with race fuel blend of ~100 octane
 

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Discussion Starter · #7 ·
My supra is a daily driver and driving around town in 100 oct is not very economical. having the water meth, I will only be using it in those moments where I am on boost. makes a lot more sense to my application. I just ordered from AIS and got some billet aluminum attachment which is going to make the install to the stock intake very nicely. Cant wait!
 

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Discussion Starter · #8 ·
http://board.tercelonline.com/viewthread.php?tid=40439

Update! I have had my meth injection system installed but the pressure switch was quite inaccurate so Rodney from AIS just sent me a new one and it's on its way. While I wait, I found the above link that used emanage blue to activate the meth injection! Now I am quite excited and will see where this leads me!
 

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Discussion Starter · #9 · (Edited)
I have since been able to use my meth injection through Emanage Blue to activate and also have 10% reduced MAF output to the ecu when injecting through EMB Auxilliary output. Current set up: dual 6GPH rated nozzles activated at MAF >= 4.00V @4k RPM or higher boosting to 16 psi. AFR is in the low 10s. I do see 4.00V MAF as early as 37xx RPM @13 psi and dialed it on on the activation point. Will see how that effects the AFR.

Planning to bump to 17-18 psi before looking to lean out to 11.0 AFR. I might get a tank of race fuel and do a few runs without meth to see where the true AFR is. I think it is inaccurate/unsafe to run pump with elevated boost and clamped MAF output. Ideally, I'd also like to get the OBD1 reader set up so I can look into the timing, but the homemade connector only worked a few times in a row and now has stopped to work completely.
 

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Discussion Starter · #10 ·
Dyno run picture here
This is my first dyno run, and I notice the distinct difference that I cannot keep a steady boost level on the dyno vs on the street. I believe the fans used in the dyno were badly positioned / not strong enough. I ended up having to turn the gain to 30% just to keep the boost somewhat level on the dyno. I did not happen to have a working obd1 datalogger and decided to keep my boost at 16 psi, 10.8-11 AFR, and this is my results.

It's not a big number but I learned a lot about gaining power through AFR tuning. I am also stoked to see my stock run of 10.8 PSI netted me 290. pretty healthy numbers for a stock auto.

I have a 3" straight midpipe that can replace the oem 2nd cat and I am wondering how I can gain 30-40 RWHP that people are claiming. I am already seeing some random boost spikes when I run to 17 psi, so wouldnt my limit still be at the octane level? Perhaps the bigger diameter straight pipe would create faster spool, less pressure and therefore less heat and some more level of safety from detonation? Some more info on DP with pump gas would be great.

future plans: higher meth concentrations to suppress knock/detonation and up the boost, If still not getting more pull then putting the straight midpipe would be next.
 

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The dyno will not load the engine the same way the street will, which is why you need more duty cycle to achieve the same target boost. As for the midpipe -- do you still have the big precat in place? If so, gains from the midpipe alone will be somewhat minimal if that big precat is still corking the system. Get a full catless downpipe and you will realize significant gains. Irrespective of the mods (to keep it simple) boost will still be octane-limited.
 

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Discussion Starter · #12 ·
this was done with both random tech hi flow cat and the stock 2nd cat. It is california after all. I am still happy to see the numbers being that it was 91 octane and water meth can allow 16 psi without a problem.
 

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Discussion Starter · #13 ·
I was unable to run high boost than 16 psi due to very weak wastegate which was weaker than the ebv. Using my EBC at such low spring pressure caused boost spikes from normal 17 psi with 19-20 psi spikes. Thankfully, the SCG-1 has boost cut. I have since installed 3 springs to the WG to created a mechanical boost peak of ~13 psi pre transition, ~14 psi post transition. Theoretically, the WG reached opens at 14 psi and ebv opens at 13 psi. After much tinkering with the EBC, I have got the boost to not spike today while going to 17 psi! It feels so good to be in control of the boost again. Played with the AFR and got it do 10.7s from 10.3s and I can feel the extra horses running.

Very exciting stuff for me and will continue to bump up the boost and maybe another dyno when I have it all dialed in.
 

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Discussion Starter · #14 · (Edited)
WELP, I hit the obd1 lean spot. when I boosted to 18psi, I would see the lean spot in the early rpms from 3700-4500rpm, but it was not very obvious. After comparing multiple data points throughout the year, it showed the pattern. At first I thought my meth water system was not consistently injecting and my emb MAF clamp was too aggressive, but it turned out that meth injection was working and lowered my afr overall and did not show the wider rpm lean condition the obd1 ecu inherently creates. talk about being 12 years late to the party... Good thing I have emb to add injector duty cycle and will see how effective it is. Next step would be finishing up my ATF temp gauge and go to the track and put down some times / get new dyno numbers.

Side note: after getting all the oil leaks fixed and having a catch can on the intake side, the EBC has been able to control boost pressure without any random spikes. perhaps the oil was getting into the solenoid and making it inconsistent.
 

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Discussion Starter · #15 ·
Back to tuning with methanol injection and currently have boostane enhanced 97 octane fuel. with the extra safety net of 97 octane, I was able to lean out the fuel from stock 9-10 afr to 11.5 in stockish boost level of 13 psi no meth. then I pushed it to 18 psi, but i can tell that the octane was not enough as timing dropped to the 12s.

Turned on my meth/water spray and pushed it to 19+ psi. the AFR seems to drop to low 10 high 9s. timing was actually gaining with each run currently to 18 degrees. I did notice a lean spot that popped up from 10.2 to 10.7 AFR then back down to 10 from 4650-4690 RPM. I was thinking what could cause a blip like this on the wideband. is it a misfire since I am running high boost and pushing water and methanol into the cylinders?
 

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Discussion Starter · #16 ·
added fan to transmission cooler and had my ecu reset in the process. tested it out again yesterday and found some good results.
boostane enhanced 97 octane, meth/water 63% 15GPH activated at ~13psi.
19+ psi 10-10.7 AFR triggered hesitation / possibly blow out misfire.
18-18.5 psi 10-10.7 AFR ran smooth out to 5+K RPM without any miss / hesitation. timing from stock ecu gave me 18-19 degrees.

I think my current IK22 plugs and .032" gap is too wide for the 19+ psi. I will run the set up in 18 psi some more to confirm
Next on my agenda is dial back on my boostane dependence and lean out some more to ~11:1 AFR. this way, more of the fuel is high octane rated methanol and lower excessive 91 octane fuel in the system.
Failsafe wise, my SCG1 innovate boost controller does a complete duty cycle cut out exceeding certain AFR, I plan to incorporate it with my emanage blue to add fuel in those conditions.
 
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