Guru

Installed my RMM intake which has been sitting around since last summer. SInce the filter was shot and I never do get very good results from K&N filters I replaced the K&N with a nice stainless steel Blitz filter. Bolted it on and put it on the dyno with my diagnostic equipment. TO my shock I had to add 25% fuel to the part throttle map and 17% at idle to get fuel correction factors back to stock. I suspect the inner diameter of the RMM intake is bigger than stock which is skewing the MAF calibration and fuel map. I then proceeded to do full throtle runs on the dyno and my Motec wideband showed super lean conditions. The stock GS400 runs very rich at 12:1 at WOT. I recorded 13.8-13.3 at WOT. WAY too lean and the ECU was pulling timing and I got knocking constantly. I added tons of fuel and got the AF ratios back to 12:1. Since my old dyno results were done in 2nd gear as opposed to 4th (don't ask I was experimenting) I can not compare results. Everything is now working well and WOT is clean and detonation free. Just one more reason to PLEASE dyno tune your intakes with an S-AFC people or you're asking for trouble. I will check the inner diameters of the intakes tomorrow with a set of digital calipers to see if that was the reason or the stock box was just super restrictive. I've never seen an intake cause that drastic of a change in AF mixture though unless the MAF housing was a different diameter.

bitkahuna

iTrader: (20)

I think the tuning shop I used said 14:1 was the right mix for my GS400!?

Guru

14.4 is perfect mix at part throttle yes but certainly not for WOT. I look also at the correction factor or how much the stock ECU is compensating in percantage scale both in short term and long term fuel trims (you need a special OBD II logger for this). Now one thing I also noticed is that it takes a few seconds for the ECU to go into open loop mode at WOT. This is common on some of the newer ECU's and with no boost is not really a problem. I preloaded it on the dyno and held it for a few seconds to a get a clean open loop reading on the run. Something my Dynapack dyno can do that an old fashioned Mustang or Dynojet can not do. It's rather handy for tuning. I will be changing out the plastic inlet pipe as well soon. I'm making a new one out of aluminum when I have time. I may bolt on my Fujitsubo exhaust as well but I've just been too busy and have to custom water cut the flanges to make my test pipes one of these days.

johnp66

I just put on an RMM intake with a K&N filter and an SAFC-II to go with Borla exhaust and TM plugs. The car was dynotuned at Balance Performance Motorsports in Atlanta and the first run showed WOT airflow at 13.5%, which the tech described as quite lean. The airflow was flat across the bandwidth, just high. The tech said I wouldn't want to run that lean longterm, that stock airflow ratio on most cars was 12%.

He tuned the airflow to a flat 13%, and that made a noticeable difference, especially in torque. But what is the stock airflow ratio on a GS400 and how much should it be pushed? How much can the stock ECU correct with these common after-market bolt-ons, and what is the longterm risk without dynotuning?

Guru

Stock ECU/stock car runs 12:1 ratio and that is optimal. It is 12 parts air for one part fuel, not a percentage scale. It gets richer than that at redline stock but all in all Toyota did a stellar job with the ECU. Bad part is that unlike other cars that run super rich, the Toyota ECU runs it perfect so I would have the dyno guys put the fuel back in to bring it down to 12:1. I am surprised it runs so rich but I also got detonation when trying to run leaner so best to keep it at 12:1 on 93 octane. If you have high octane race fuel you can bring it up to 13-13.5:1 no problem. Other cars I can run leaner like 13-13.5:1 but not this one despite timing being rather consrvative at 21 degrees at redline.
Oh and the reason why it was so high I suspect is due to the larger diameter of the MAF housing tube. I will confirm this tomorrow but I am almost positive this is the reason for it to cause the lean condition. YOu can correct for it with an SAFC but is certainly dangerous if not tuned and certainly not well engineered. We are releasing our first intakes for the WRX next week and we had the aluminum spun to the exact same diameter as the stock MAF housing for this very reason.

johnp66

I saw a significant jump (almost 8hp) when the airflow was lowered to 13. Would I get more going to 12? I read your earlier caution about strapping on an intake without tuning. Realistically, what's the risk running at 13.5 or higher?

Guru

Basically you'll detonate and kill your bearings. Eventually you'll see enough damage to the piston and bearings that you'll need a rebuild. 13:1 is too lean for this car. I got detonation going from 12:1 to 12.2:1 which tells you how knock sensitive this car is depite the mild timing curve. I'm actually surprised you don't have any now but most likely you do and just don't know what to listen for. Most people don't know what detonation sounds like.

johnp66

Dan, glad I got it tuned as soon as I put the intake on. And I'll call BP back to set another visit. The BP tech had another tech listening for knock at WOT and they were confident they heard no knock -- although I wondered how they could hear it over a WOT G4. I have set the SAFC II to the knock monitor and it fluctuates wildly as I rev, but settles back to 0 once I stabilize the revs. But just now the idle showed a reading of one. The SAFC manual says noise will show up in the readings, but I now suspect it's not all noise. Is there a best way to monitor the knock until I get back to Atlanta. Is the knock history reading reliable on SAFC? Sorry to bend your ear and thanks again.

bitkahuna

iTrader: (20)

Wow John - I've never had the knock sensor read anything other than 0. Hmmm...

johnp66

And your airflow is higher than mine? I talked to BP this afternoon and they said the tech would pull my dynocharts and get back to me. No word back, but it was late when I called. I was told they monitor knock throughout the test and that no one leaves their shop if there is any knocking. He said it could be the setup or wiring on the SAFC.

I don't hear anything, no metallic pinging, but then it doesn't knock at low rpms and I probably wouldn't hear anything at higher levels. And the acceleration is terrific - much more torque on the low end and it pulls stronger all the way to redline. By the way, BP uses the Dyno-Jet. I ran the SAFC graphing chart on the way home and it definitely shows low level knocking on acceleration, which I am no longer doing. But it does fluctuate on acceleration. And no doubt the printout I have says afl is 13 at WOT, well above Dan's suggestion of 12. Dan are you using the early RMM intake or the new version? Mine is the plastic version with a heat shield. But I am taking it easy until I get more info from BP.

johnp66

Talked with BP just now and they insist this is noise causing a false reading on the SAFC II. They said my WOT was 12.6, not 13. I was confused because the graph is a straight line 13 to 6k, and the slight trailing off didn't look significant at the time. On closer examination, I can see that it's in between 12 and 13. They've tuned other GS4s, including a supercharged version -- and they have another SC scheduled for tuning. There are several references to knock and noise in the manual. Paul, my SAFC was clipped, not soddered. Sam said it would be easier to work with when I install the SC down the road.

Guru

I have a metal RMM Intake. It has the velocity stack and then the MAF adaptor with the heat shield. Now keep in mind different widebands sometimes do not correlate with one another so as long as you're not pinging, leaner is better but from my experience you can not go any leaner than stock AF ratio on the GS400. It does get a tad richer at high RPM's and you can make the AF flat across the board to get a bit more power. Also, remember that you have that time delay before it goes into open loop mode so make sure your lo throttle settings are giving you a proper mixture as well.

johnp66

Dan, I definitely do not hear a ping -- and you can bet I have had several people helping me listen for it. Wouldn't predetonation show up as a jagged power curve on the Dyno-Jet chart? Seems like I remember reading someone questioning a ragged Dyno chart regarding a test of TM plugs, which I also run and believe in strongly. My point isn't the plugs, but the irregular power curve. Wouldn't predetonation result in a brief but sharp drop in power that the Dyno would plot? My chart deviated from trendline no more than 5hp from across the chart. -- john

Guru

It may or may not show up on the chart as jaggedness. THat is not the correct way to measure. Best way is with headphones and a mic near the stock ones. Roller dynos are not very sensitive so it is difficult to see small changes. My Dynapack dyno has no roller so is far more sensitive than the old fashioned rollers style dynos.

lexusondubs

iTrader: (9)

is this only on the gs 400 and how will this have a effect if any if i put a rmm intake on my gs 300 thanks shawn