Apexi-Neo Tuned and Dynoed Today 3/6/09
03-19-09, 01:59 PM
#31
Lexus Champion
i have tuned LOTS of hondas on dynojets (this is my first lexus...ive spent the lst 16 years tuning and building hondas) and in my experience, there is very very little difference between a dynojet and the street. (if the dyno is setup correctly) i allways tune for 13.0-13.5 for n/a power on the dyno. i have tuned just shy of 100 hondas and have not had to retune a single one of them after dyno tuning. maybe im lucky, but i would like to think otherwise 
So, tuning a 3000 pound Honda to 13.0 or 13.5 will be stressed more and therefore tend to show problems such as detonation from too hot of spark plugs or a mediocre injector or many other possible problems. Tuning the 4000 pound (street weight with driver) Lexus is less stressful and less likely to show problems. Therefore my advice is go slightly richer on the heavier vehicles especially since the small gain in peak power is really only bragging rights and comes with an extra does of potential trouble.
When a dyno pass is made the car is slowly brought up to speed in the gear intended to be used and then a pull is made. It is then usually unloaded and even turned off while that pulls data is reviewed and possible changes made. This allows for just a few seconds under full load.
On the OTHER hand a street or track run takes 15 to 30 seconds of full throttle/load operation and temperatures tend to get much higher which definitely effects the detonation threshold of the engine.
Hondas also are usually designed for higher than 6300rpm operation whereas that is the fuel cut on the GS4xx. The Lexus rods, pistons and rings are arguably not as strong as the Honda that is engineered in some cases to 8000rpm (or more).
Comparing the "success" of tuning Honda engines is arguable as well. No insult intended but the "goal" of most Honda owners is usually more aggressive and the "lifespan" expectancy shorter than the Lexus owners. What is the average mileage lifespan of a tuned Honda engine driven by a young aggressive driver??? With NO rpm limiter and a manual transmission? How does one judge the long term durability of a Honda tune?
Also, 5-10hp is MORE of a percentage and MORE important on a 150whp engine moving a 3000lb vehicle than the same power change on a 250whp engine moving a 4000lb vehicle. The Honda engine is also LESS expensive if it breaks. The risk reward is totally different between these two engines.
Regarding my original statements I said "MAY" be too lean and be "CAREFUL" and listen to the engine as well as use quality fuel. Still EXCELLENT advice... even for Hondas!
Doing some quick searches to locate some Lexus dynos with A/F ratios turned up this from the IS-F forums. Stock ratios from 12.5 down to 10.8.
Power tuned gives a momentary bump to 13.6 with most of the rest below 13.0. Not claiming this tune is perfect just a quick example showing the stock ratios are fairly rich.
Worth noting that the dangerous torque peak area on this engine (5000rpm) had factory tuning at 11.8 and the tuned number at 12.6
03-19-09, 02:30 PM
#32
Lexus Champion
I guess we can agree to disagree. In my previous post I wasn't suggesting running at 14.7, all I was saying is that is complete burn, hence the reason I mentioned tuning for a 13.5 or so ratio. I personally haven't seen any Lexus vehicles that have dynoed at 11.0 (avg across the board) factory, MAYBE hitting it at a couple of spots for a split second but not what I would consider enough to say the car is tuned for 11.0.
I agree running rich is safer but I don't think the OP would be over the line of safety running a 13.5 ratio and could probably pick up a decent amount of power from 13.0 and still be well within safety margins. The timing margins on a stock Lexus are quite wide and will pull timing before any serious detonation occurs though I highly doubt that there will be any detonation issues running premium fuel.
Either way, IMO there is power to be had and still be well within safety at 13.5 or so.
I agree running rich is safer but I don't think the OP would be over the line of safety running a 13.5 ratio and could probably pick up a decent amount of power from 13.0 and still be well within safety margins. The timing margins on a stock Lexus are quite wide and will pull timing before any serious detonation occurs though I highly doubt that there will be any detonation issues running premium fuel.
Either way, IMO there is power to be had and still be well within safety at 13.5 or so.
03-21-09, 07:00 AM
#33
Pole Position
Thread Starter
Hi Guys,
After the tune i was told that the ECU kept on interfering with the tune.He said that if i wanted he could lean it out a bit more but preferred to keep it as is for safety.He also stated that it would not stay in the gear he wanted as it kept on kicking down when he powered it. Could this be the be the reason why the torque numbers are so way below Nick's (Rock-a-Lex). I am not into street racing but love to feel the power. Its it possible to re-calibrate the Air/Fuel ratio with re-dynoing/tuning ($250).
PS i only use 93 octane fuel.
Clive.
After the tune i was told that the ECU kept on interfering with the tune.He said that if i wanted he could lean it out a bit more but preferred to keep it as is for safety.He also stated that it would not stay in the gear he wanted as it kept on kicking down when he powered it. Could this be the be the reason why the torque numbers are so way below Nick's (Rock-a-Lex). I am not into street racing but love to feel the power. Its it possible to re-calibrate the Air/Fuel ratio with re-dynoing/tuning ($250).
PS i only use 93 octane fuel.
Clive.
03-21-09, 05:19 PM
#34
Clive, the same guy that tuned your car recently tuned mine a year ago. At that time he mentioned that it was a PITA to hold the particular gear he wanted...he must have done about 10 pulls total (at least)- including the initial 3 baseline pulls. The car was on the rollers for about 1.5 hours. Next weekend is The Day for me. I will call Monday morning and make an appointment for next Sat...I don't want anyone to get their hopes up; just in case I only pull 285whp or so. 
I'm hoping it will be higher though, we shall see!
I'm hoping it will be higher though, we shall see!
03-21-09, 06:11 PM
#36
Pole Position
Thread Starter
Hi Guys,
Nick he did say it was a PITA, He did 9 pulls plus the base line.
I wish i could find a cheaper place that can tune the Neo on an automatic for cheaper in the NYC area.
Clive.
Nick he did say it was a PITA, He did 9 pulls plus the base line.
I wish i could find a cheaper place that can tune the Neo on an automatic for cheaper in the NYC area.
Clive.
