TailHappy

Went out and dynotuned the car this weekend after recently installing the PFC. The base mod maps were absoultely spot-on for my car. I guess the high-flow Bonez cat and the street port effectively negate the built-in richness safety factor. I didn't have to make any adjustments at all to get high 11's from 3000 up at 12-13lbs boost. Final corrected numbers were 287rwhp and 246rwtq. Not to whine, but that's sort of a rip since they subtracted horsepower for the correction, but my stock IC was heat soaked at 50C, so I don't think I was truly benefitting from the cooler temps! Actual hp was nearly 300.

If anyone wants, I'll scan in the graphs sometime and post them.

skotx

I always like to see graphs of other people's dyno runs, so post em up if you can. Was this on a Dynojet or some other type?

-Scott

TailHappy

Yup, a Dynojet. I'll try to scan them in tonight or tomorrow, then.

Badog

I think 300+ RWHP is but a upgraded IC away.

TailHappy

Oooh, I just peed my pants over the last comment...

I agree though. 50C is hella hot. I have some friends that are running FMIC with similar mods that have broken well into the 300's and are seeing intake temps that stay in the 20s. I haven't been all that impressed with the acceleration up to this point (I'm just jaded), but I went out last night while it was cool and was very amazed at the difference with intake temps hovering around 30. First cool day we've had since I installed the PFC. I was convinced my boost must have gone too high but it only showed a peak of 0.72 bar, with injector duty of 81% and knock of 40. That oughta be about perfect!

Sorry for taking so long to post the charts. I'm really hoping to get to them tonight....

TailHappy

Oh yeah, and for the record it looks like a totally heatsoaked stock IC results in intake temps of 72C. I found myself waiting in line in a parking garage for nearly an hour, and that's where it finally peaked out (with the radiator fans on high, coolant temp of 88C).

TailHappy

Learned something else, too, while I was at the dyno. After my intake temps had crept up while idling, he recommended I lightly blip the throttle at 2500 rpm. Due to the increased airflow, the temps went down a full 10 degrees in just a couple of minutes!

SPOautos

Did you happen to check your egt's during the run???

STEPHEN

TailHappy

No, I don't have an EGT gauge and the shop didn't either.

nocab72

TailHappy - Becareful checking your PFC MAX setting to read your peak boost. My PFC MAX setting is always lower than I see the boost gauge hit. ie I'll see the boost guage hit 14psi and the PFC still only read a max of .9bar.

Not sure why it happens this way...can anyone explain? Does the PFC lag and miss the spikes?

K

Badog

Good point. I take that forgranted since I use the AVC-R for boost. There is a WIDE margin between what the two show for peak.

TailHappy

I read a thread that argued that the difference between a gauge and the PFC is the difference in gauge and absolute pressure. In other words, one reads on a scale starting with 0 pressure and one reads a scale that starts with atmospheric pressure. Thus the 1-2 psi difference. Most of the time I've been keeping an eye on my boost gauge and they've been corresponding well. Never seen my gauge go above 12 (which is where I want it, PFC reads about 0.72), where there for a while before I got the PFC it was spiking to 14 at the transition. I think if you keep an eye on your duty cycles, intake temps, and maybe even knock, you should be ok.

I'm posting the dyno sheets tonight, for real!

skotx

What do you have your boost set at, and are you using the PFC as your sole boost controller?

I have boost set at 0.8 on the PFC and it'll peak in the low 0.7s, but my gauge will show 0.9. So I'm apparently overboosting, which is fixed by adding backpressure or porting the wastegate.

It's well known that your PFC boost and gauge boost will most likely not match. Regardless of why, is it safe to regulate boost with the PFC alone? Does anyone see their desired boost level (not PFC peak) on their boost gauge?

I need to run some tests when I put my midpipe back on... emissions test time.

TailHappy

I initially set my boost based on the advice I had seen on the forum, but then I had a friend recommend some interesting changes. Instead of setting your target number for the level of boost you want and then playing with duty cycles to get it to actually get there, he recommended setting the target high, and then the duty cycle low. Unexpectedly, the end result is boost that reaches peak quickly, but then stays rock solid unlike the spiking I was seeing from high duty cycles. I'm going from memory, but for 12-13psi, I think I'm set at 0.85 and something like 66% for the primary and 0.85 and about 64% for secondary (I'm shooting for the 0.7 - 0.75 range, and my peaks haven't been higher than 0.73 so far). I'll try to remember to check the settings on the way home. Bottom line is the car is feeling MUCH stronger set up this way. Give it a try and let me know what you think (start with low duty and work your way up so that you don't overboost!!!).

As far as "overbooosting", it's difficult to tell. It's arguable that what the PFC says is the more correct number since it's reading what the engine is actually seeing. We have this magic "12psi is safe" rule, but it's not clear where. Personally to be safe, I don't like seeing more than 12-13 on my boost gauge, backed up with safe duty cycles, A/F ratios, and low knock readings. With a stock IC, 1-2 psi doesn't buy me much of anything and isn't worth the risk.

And now (finally) the money shots! ...

TailHappy

This was the dyno sheet that came with the car when I bought it. It was using an XS programmed ECU, stock cat, and a stock flywheel. I think everything else from my sig up above was the same. Unfortunately there's no A/F ratios, but the car smoked at redline, so it was probably rich. Boost was set at 12psi according to my gauge.

TailHappy

This is my latest sheet. As I alluded to above, I added a Bonez hi-flow, a 9.5lb Al flywheel, and the PFC with the base mod maps. The runs were all done in 4th gear. On the advice of others, the boost was adjusted so that it would build up properly given the lack of load from the dyno. Unfortunately I don't remember exactly what they were set at, but the boost gauge never went above 13psi and spent most of its time at 12. As noted before, intake temps stayed in the 40s and approached 50C.

I think it's interesting to see how much smoother the new curve is. The transition area was pretty funky originally and the old boost spike is very evident in the torque curve. Unfortunately, I don't know what the cat was responsible for vs what the PFC did, but obviously the two combined resulted in some nice gains! Not to mention all the little things the PFC affords (not the least of which is the total disappearance of my very nasty 3000rpm stumble and constant stalling at idle!). I love the PFC (and don't regret not waiting for the AEM)!!!!

spyfish007

I'd be happy with your HP numbers with your mods. Your AF sounds good too. Side note: sometimes boost creap is incorrect tuning ....search the forum if you want to know more.

TailHappy

Thanks spyfish. The guy at the dyno was impressed that an RX-7 made it through without breaking . Are the low end A/F ratios ok? I noticed they're high, but I've seen others like that. On the street I never floor it before 3500 or so anyway since it seems to close to lugging. But I am getting stumbles down there (closer to 1500-2000 range) when shifting or revving. I've been playing with the acceleration enrichment to try to fix that. It's worst when the engine's cold.

Also worth noting is the wideband was shoved in the tailpipe, so my cat was probably cleaning things up a bit. Otherwise I'd be a hair nervous about being that close to 12.

forcefed1

hey TailHappy, what did you think of teh shop you were dynoing at?
I was looking at going there myself about 1.5 hrs away
were they able to give tuning advise?
how was the price.
maybe you should PM me since it;s out of this thread. any chance you want to mee there next time and I'll do my car too?

spyfish007

I think it looks good overall. I think I need to to clarify what rpms you make say 7 lbs of boost. 12.5:1 would be good for 7 lbs of boost trailing to mid to high 11s at full boost. I've taken lots of fuel out of the accelerator map to get it to smoth out. If it is only tip in I'd stay away from adjusting the inj map ... which it sounds like you got it down.

Oh yeah, if you have stock twins I'd say have fun at 2200 rpm, etc ... that is the awesome part about the seq response. I used to stop it at 2500 all the time. Nothing like low end torque!! If you aren't going to use it, then get a single turbo or go non-seq. There are plenty of times I miss that seq mode.

spyfish007

Oh one last thing. I think you should spend some time tuning the car at the transition. You have a nice dip there. Some might say that can't be tuned out ... I say whatever. There are many, many things you can adjust: precontrol rod length, pills, duty cycle, transistion point(thanks datalogit), fuel, and ign timing that can smooth that out.

Wade

iTrader: (1)

Tailhappy:

You're right, the PFC reads absolute pressure, that is why the display is almost always a little low compared to what you see on the boost gauge (it depends on your altitude).

Stock ECU and Power FC run a bit lean below 3500 RPM. This is common but still problematic for some cars. I know of two cars that will knock at full boost and low revs (one is practically stock, one is fully modified). I richen my own car up a bit down there to prevent it. It still isn't a good idea to lug the engine as it will eventually result in knock. Flooring it at lower RPMS is different than lugging it around.

You should wideband your car with the probe before the cat sometime, you might be surprised how much richer your programming actually is. You may be in the 10's. Regardless, the cat will only cause the reading to be leaner than actual so your a:f is at least safe (if not optimal).

Wade

TailHappy

Thanks for the replies, guys. As far as the transition, it really doesn't feel nearly as bad as it looks. I'm probably apt to just leave things well enough alone!

I'll probably add a little fuel around 2000. I feel it surge lightly when cruising at a constant speed, especially if the AC is on. But knock looks great. I autocrossed this weekend and it never got above 30. I have seen it hit 100 before, so it's not just that the sensor's insensitive in my case.

TailHappy

A couple more things for anyone that cares...

First, I finally got around to checking my exact boost settings. They are:
Pr 0.85 64%
Sc 0.85 62%
Again, I generally see 0.70 as a peak, although if I take it all the way to redline, it'll peak out at 0.73. However, setting it this way seems to make it come on stronger and stay steadier vs setting the targets lower and the duty cycles higher.

Also, I used PIM to ADD a little fuel in the 2000-3000 range and it seems to have improved throttle response and surging as well as the little bobble on shifting. Still have a stumble with quick throttle at idle, so I still need to mess with those enrichment numbers some more...