Disappointing Dyno Runs Today

[cdssolara]

I brought my car in for a dynotune today. The shop I went to used a Dynojet. The best I could get was 246.1 fwhp and 242.1 ft-lbs. Not bad numbers, but considering that I just got Jim@ForeignAffairs heads installed along with a 7 psi pulley, I was pretty disappointed. Last year, with a 5.5 psi pulley and my current Apexi WS catback, I ran 246.6 fwhp and 232.9 ft-lb. This was also on a Dynojet, by the way, so I should be comparing apples to apples. At least I got some gain in the torque. Maybe that explains why the car feels stronger, even though the numbers don't back it up.

The main problem seems to be the fuel delivery. I was running lean the whole time, even with S-AFC adjustments at +25% from 3000 rpm up. When we tried to go higher, the ECU couldn't deal with it and retarded the timing. The lowest that my air fuel ratio could get to was 13.5:1, which is too high. I don't know if just getting bigger injectors will help. I know Ericsol has been using a product from Split Second to control the timing, so maybe that is the way to go. There is some good news, though; it doesn't appear that I had any problems with the knock sensor.

I'm sure headers and a new Y pipe will help, but the fuel delivery seems to be a bigger issue. At this point, the additional boost from the 7 psi pulley would appear to be wasted. I'll keep you posted as I research this further.

[Mole]

oh man.. bummer. and you think the fuel is the issue?

[cdssolara]

Freeing up the exhaust would help, too, but the fuel delivery definitely seemed to be a limiting factor.

[EricSol]

I have tried 7psi and it didn't make any more hp so I shelfed it and I am concentrating on making hp at 5.5psi. I tuned a 6psi Camry yesterday with Jim's heads, AFC and injectors and it was at 240fwhp with a safe 12.5-1. What I found intresting was it was pulling some timing here and there leaving me to believe that even with lower comp that 5.5-6psi is it for our CA 91 piss gass.

The Split Second unit can adjust thru anything and does timing thats why I switched when the Afc couldnt adj. enough to get my a/f right. Raise your pressure with Jim's free mod b4 spending $ on the SS.

[cdssolara]

I have tried 7psi and it didn't make any more hp so I shelfed it and I am concentrating on making hp at 5.5psi. I tuned a 6psi Camry yesterday with Jim's heads, AFC and injectors and it was at 240fwhp with a safe 12.5-1. What I found intresting was it was pulling some timing here and there leaving me to believe that even with lower comp that 5.5-6psi is it for our CA 91 piss gass.

The Split Second unit can adjust thru anything and does timing thats why I switched when the Afc couldnt adj. enough to get my a/f right. Raise your pressure with Jim's free mod b4 spending $ on the SS.

I had Jim do his fuel pressure regulator mod when he installed my heads, so that is already a done deal. I was reading some of your old posts on SC3 about pulling timing on higher boost and higher S-AFC settings, so now I've had the same experience. At this point, I'm not sure if I should focus first on fuel delivery, exhaust mods, or just try the SS unit. Any recommendations, since you've done all three?

[EricSol]

The s/c and exhaust are the 2 best mods I have done, the other stuff is there to support the 1st 2. Just for your own info; I am staying at 5.5psi even after the heads, I just don't think we have the fuel to support any more boost and I am tired of running race gas.

[cdssolara]

Thanks for the feedback, Eric. I will probably think hard about going back to 5.5 psi myself. I only went to the 7 psi because Jim thought it would work OK with his heads. By the way, I got a CE light today, so I may have knock sensor problems after the dyno run. I seem to have lost some power, so the ECU seems to be pulling timing. I'll have to find someone with an OBDII scanner to confirm it's the knock sensor again. I had Jim replace my earlier one because it was having the usual problems.

I may be placing that header order sooner than I thought.

[EricSol]

I'm getting ready to send 3 systems to the coaters so if you want one it should be in stock.

Heres a compression ratio calculator, about 1/2 way down the page. Play with it and see what you come up with, I did and think at 9.4-1 I'm staying at 5.5psi.

http://www.fbody.com/calc.htm

[cdssolara]

That's an interesting calculator. At Jim's claimed 9.4:1 CR with his heads, a 6 psi pulley gets you under what the SC with stock boost would give you. So you think that even that is right at the limit of safety?

Re: that Camry that you were tuning that was still getting timing retard...Were you determining the timing retard via the SS?

I'll be getting back to you soon regarding the headers, and possibly the exhaust. I understand Jim has been in discussion with Jose about a quieter muffler. Anything happening with that?

By the way, which color for the headers is closest to stock? Since this will have to pass a visual, I'd want it to look as inconspicuous as possible. Jim Damman's header looked really nice, but the color made it obvious that it was aftermarket.

[cdssolara]

I got an OBDII scan yesterday, and it looks like I blew knock sensor #1. The good news is that the #2 sensor, which was replaced earlier, didn't blow. I guess that means that the replacement sensors that Toyota is selling are less sensitive than the OE units. The bad news is that I'm going to have to go through the expense of having the #1 sensor replaced. Obviously, I should have replaced both of them together, but hindsight is always 20/20.

I think I'll also be ordering the JP Performance headers. I haven't decided yet if I'll stay with the 7 psi pulley or go back to 5.5.

[SC V6]

what did it say when u blew it? Just tonight I was driving my car hard, and the check engine light came on, then when I floored it, the car turned the trac off, off completly.. I got home and checked it, and it said Bank 2 Knock Malfunction.. I turned it off, and put my fuel up some... it hasn't come back on, and I was drivin pretty hard again... whats the deal?? my fuel was perfect... only thing was it was a little too rich at lower rpms... so I turned it down some more on the low, which is why I think it went off.. whats the deal?
thanks
Scott

[cdssolara]

what did it say when u blew it? Just tonight I was driving my car hard, and the check engine light came on, then when I floored it, the car turned the trac off, off completly.. I got home and checked it, and it said Bank 2 Knock Malfunction.. I turned it off, and put my fuel up some... it hasn't come back on, and I was drivin pretty hard again... whats the deal?? my fuel was perfect... only thing was it was a little too rich at lower rpms... so I turned it down some more on the low, which is why I think it went off.. whats the deal?
thanks
Scott

The first time I got the CE light, which was almost a year ago, I got a code P0330, which is the bank 2 knock sensor malfunction. The light would go on and off periodically. I was never really sure if the sensor was blown, although I suspect it was not. I think that my car was running right on the edge of being too lean, and on certain occasions I would push the car a little too hard, and the knock sensor would send the signal to the ECU and it would retard the timing for a short while. The light would usually go off after a couple of days, and sometimes wouldn't come back on for weeks or even months.

When I got the heads from Jim@FA, I had him install them and also replace the #2 knock sensor, as well as replacing my 5.5 psi pulley with a 7 psi pulley. Things seemed OK, and the car felt like it had noticeably more power. Jim had warned me that after 5000 rpm, my exhaust system would probably not be able to clear all the exhaust gasses because I had the stock manifold and Y pipe, along with Apexi WS catback. He recommended that I get the JPP headers, at least, and felt that their catback would be a good investment, too.

As it turned out, he was correct. When I got the dynotune last week, the car did great till just under 5k rpm, and then the CE light came on and I got timing retard. This happened on every run, even when the fuel was adjusted. In every instance, the A/F ratio never got below 14:1. The CE light was turned off by disconnecting the battery, so when I drove off I had no timing retard. The next day, I got the CE light again. It turned off this morning, and I seemed to have all my power back. As an experiment, I tried to push it again, and at 5200 rpm, the light came back on.

The code I got this time was P0325, which is the #1 sensor. From what I understand, it is easier to get the malfunction in the #2 sensor than in the #1 sensor. I guess this means that the the replacement sensor is less apt to malfunction than the OE sensor. I'm not sure if I need to replace the #1 sensor, but it seems like it would be a good idea.

Bottom line, though, it seems that the 7 psi pulley just causes our cars to run too lean under max boost. In my case, I thought maybe it was due to my stock injectors and need for headers. Scott has both, as well as the cylinder heads and he's getting the CE light, too. In his case, his A/F ratio was 12.5:1, which is good. So, even then there is detonation and ignition retard. It's beginning to look like 5.5 psi is as much boost as these cars should get.

[shidosha01]

[quote="cdssolara. It's beginning to look like 5.5 psi is as much boost as these cars should get.[/quote]

I've got the Jp Headers and Exhaust. SAFC II and 6lbs. pulley ready to install. I thought 6lbs. with 93 octane in my area should be fine.

[cdssolara]

[quote="cdssolara. It's beginning to look like 5.5 psi is as much boost as these cars should get.

I've got the Jp Headers and Exhaust. SAFC II and 6lbs. pulley ready to install. I thought 6lbs. with 93 octane in my area should be fine.[/quote]

You're probably right. I keep forgetting that not everyone is limited to the 91 octane premium we have in CA. Still, I think Scott is able to use higher octane gas, and he seems to be having problems with his knock sensors.

[EricSol]

I ran 5.5 for ever on 94 octane and I still have the original knock sensors. Now that I have lower compression I might try 6 but I don't think 7 will work on 91 and I am done (for now) mixing in $5 a gallon race fuel.