#11
|
|||
|
|||
Re: Tuning W/I via Humidity Sensors
Hi,
it means with the current w/m flow the engine starts knocking before I reach the maximum torque as I advance ignition. If I would up the flow, I would at some point not be knock limited anymore. As I would advance ignition triming any further, torque would just drop as peak pressure is reached to early. But there would be no knock. Thing is that I only use a 3l tank. On a track with lots of WOT, e.g. Spa, it only lasts some 15 to 20 minutes. On tighter tracks, e.g. Anneau du Rhin or Bilster Berg 3l last for more than 30 minutes. I am usually not for longer on track within one session anyhow. On the road it may well last 200 miles excluding longer 130mph+ streches of Autobahn driving. |
#12
|
|||
|
|||
Re: Tuning W/I via Humidity Sensors
That's what I don't understand. I am using w/m to not be fuel knock limited. So I spray around 30% to fuel.
Do you think it would be wise to install a 20 liters tank and then increase the w/m flow? Or is really how you want it tuned? |
#13
|
|||
|
|||
Re: Tuning W/I via Humidity Sensors
30% water to fuel or mix to fuel?
I know I have not hit the limit in terms of what I can achieve with w/m injection yet. I am happy then egine does not blow up in first place. :-) It is a Lotus Elise S1, 20l is not really usefull to carry around. It is a very small and light car. I may consider installing a additional 5l tank for track use. But doing a 5min break every 20 minutes is also nice. Drink, refuel, ... |
#14
|
|||
|
|||
Re: Tuning W/I via Humidity Sensors
Quote:
Presently I am running 18psi on a GT2560R turbo / Toyota 1.5L @ 13.5 AFRs @ 6800Rpm / injecting 350cc post turbo. Now the issue is that I do not know how much the engine could handle more boost with no issues, that's why I tried to make a more efficient tune. |
#15
|
|||
|
|||
Re: Tuning W/I via Humidity Sensors
ww2 engineers did the tests up to 1.5:1 water to fuel.
The slope went always one way. more boost + more water = more power. So there is plenty of headroom from your 350cc jet :-) What engine is it? A 1FZ-NE? Forged pistons? Cast pistons are more often than not the first thing to go sauer. I still suggest to install charge cooling. It combines well with water injection. I have seen intake air temps drop 10-20C max using water injection. More with adding methanol, even more doing precompressor injection. Doing direct port injection, there is barely any IAT reduction, but I can still benefit to a similar degree, if not even more. I have no dyno, so can't tell you in terms of % power/torque. A 10-20C drop is rather little compared to what a charge cooler does. Even a small one will reduce IATs by 30 C or more. The decent ones get you to 10C above ambiernt, so in your case about 80-100C reduction in IAT. That is why I suggest let a charge cooler do the charge cooling and the water injection do the in-cylinder work. They both add to the performance potential. if your current tune is already at best torque, so not knock limited, you only can up the boost to get more flow/power in its current configuration. If your engines knocks before hitting best torque upon further ignition advance, add more water/methanol and try again. Where the limits of your engine build are, you need to do your own research or blow an engine. As you run no charge cooler, you may try precompressor injection. Regarding AFR, I have found that such a "lean tune" provides good power, but generates considerable heat. I have only observed this on track. 12:1 yielded about 85C coolant temp and the 13:1 about 90C on that particular day. Both were with w/m injection. Nice thing was fuel consumption was significantly lower in that session. On the road doing short burst of WOT, it probalby won't matter. temp wise My cylinder air distribution is not that uniform with Nr.1 running a tad leaner. The plenum is not designed for forced induction. The plenum chsmber has a side entry and a uniform cross section along the width. This leads to more airflow at ther first cylinder and less towards the other end. Running the engine at 12:1 keeps them all somewhere around this number. It lowers overall combustion temps and cylinder head and valve temps with it. In your case also turbo temperatures. Riceracer propagates 11.8:1. This is rich best torque. It adds safety and costs barely any power vs. a leaner all out tune. |
#16
|
|||
|
|||
Re: Tuning W/I via Humidity Sensors
Quote:
|
#17
|
|||
|
|||
Re: Tuning W/I via Humidity Sensors
Hi Alex,
you probably inject a mix with high methanol content. That would explain the low air temps. Also your turbo charger seems to run in a really efficient range. I'd still consider adding even a small charge cooler. I use a PWR barrel charge cooler. I barely adds any volume. http://www.chargecooler.co.uk/index....index&cPath=67 Spool time should not really affected by a few liters of volume, especially as you have a throttle body right on the intake plenum. Your turbo is still spinning pretty fast after you press on after gear change. A front mounted one might add a few ms. your turbo pumps out 100 liters per second at 1bar or 200l at 0bar. To fill a charge cooler of 10l of volume after a gear change at full chat from atmospheric to 0.5 bar takes mere milliseconds. From 0.5 to 1 bar an other few more. You won't feel it. You plenum does the same as mine. Air speed drops as air is consumed from plenum intake to the last cylinder. Usually the first one gets the most and the others less. The design itself, e.g. inlet angle and diameter, can change the distribution to a degree. But in general it fits the picture. First one gets the most air and the last the one the least. In my case 1 is lean and 2-4 are about equal . In you case 1-3 are equal with 4 being rich :-) The ideal forced induction plenum with a side intake is either fed by a secondary plenum and a long slit. The secondary plenum having a conical shape with the diameter reducing to 25% of the cross section. The other solution is actually to reduce the cross section of the plenum chamber itself from 100% to 25% at the last cylinder. This way air speed and with it pressure and flow stay uniform across all 4 runners. see: http://honda-tech.com/welding-fabric...folds-3016531/ and: http://www.clubgti.com/showthread.ph...final-cut-done If I ever being bothered I might try it, but space is really tight. |
#18
|
|||
|
|||
Re: Tuning W/I via Humidity Sensors
Quote:
|
|
|