The Rig

iTrader: (13)

In the long hunt for quicker spool i was reading some info and it got me thinking, where does the efficient power of the TD05H run out ? i mean, im running 1.35 Br boost pretty much all the way to 6000 rpm but i can not go past 19 degrees of total timing from around 4k to 6k at WOT full load, now at 1.35 bar 19 degrees is pretty good but it got me thinking, if is the turbo just chuffing in hot air rather than extra air at this Bar at these rpms hence im not making more power just adding hot air ?


If i tapered off from 5k to 1.2 bar maybe id get a couple degrees more timing but would that result in better power than current ?

Don Clark

Have you tried plotting out what you want to achieve on the relevant turbo's compressor map ??

Some useful info here

http://www.stealth316.com/2-3s-compflowmaps.htm

The Rig

iTrader: (13)

Cheers bud, some good info there but a bit mathmaticall complex lol

Havent plotted anything out, just mapped the car for what feels good on the road, it drives fine at 1.35 bar at 5-6k full load but after reading what i did about turbo efficiency it got me thinking am i pushing too much boost top end with no benefit, altho on the road it still feels fine in these conditions but what feels fine and what is fine are 2 different things ha

cheers

Bazil_SW

iTrader: (4)

The empirical way might be to dial back timing a few degrees across the board and keeping everything else the same, adjust boost and log the usual things + volumetric efficiency for a range of psi, then overlay the results. Start 'low' and work up and you'll find that the VE (considered across the rpm range) peaks then decreases again. At the peak the compressor is running most efficiently, and after the peak the compressor is just blowing hotter air that is less dense and more prone to det.

This is how I started tuning my car, using a mechanical boost controller to easily adjust boost and took the average of 2 or 3 pulls worth of data for each boost setting, because my tuning road is not completely flat (part up and downhill).

The other way could be with a thermocouple just before the intercooler.

The Rig

iTrader: (13)

Ok will check some previous logs and see, am i looking at MAF voltage compared to boost load for VE ? ( all new to me this is now )

cheers

Bazil_SW

iTrader: (4)

You can select VE as one of the calculated log items in romraider, otherwise it needs to be calculated from various measurements taken at the time. Best to collect some new data with ve selected or at least the items needed to calculate it. If you Google it or search romraider forum you should find out what's needed.

(But hopefully you can just select it in romraider logger)

The Rig

iTrader: (13)

ok cheers, i dont use romraider so will google whats needed.

after a bit more reading i think 1.35 bar to the redline on a TD05H 16g is fine tho from what others are saying

cheers

bludgod

iTrader: (3)

VE can't be logged directly in ESL - however you can log enough data to get you there if you really wanted too. The compressor map for the TD05-16g should be pretty close to the original mitsubishi one:




TD05-16g Compressor Map


Now if you plot on that *roughly* for your car - lets assume say 95% VE for your engine then you should be able to get a maximum pressure of:
2000rpm / 0.9bar
3000rpm / 1.4bar
4000rpm / 1.8bar
5000rpm / 1.8bar
6000rpm / 1.5bar
7000rpm / 1.2bar

Now - this doesn't take into account a lot of things (like pressure drop across your intercooler, engine VE changing at different RPMs, how much your pressure your particular setup can take, exhaust housing limits, knock threshold of your fuel etc.). This is the "raw" output of the compressor at it's very limit so you then have to scale back to account for the other parts of the system. But don't think of this in terms of a target value - just consider the shape of the boost plot instead. You can see clearly 4000-5000rpm you can make a lot more usable boost than you can at say 6000rpm. So your boost curve on the car would be fairly similar, spool up around 3000-3500 then 4000rpm full chat up past 5000/5500rpm and then begin to taper as you approach the rev limit.

The plot points you can do in excel with a little messing about:




So you can see the compressor map and then the mostly guesswork VE lines on top for different RPM's. So run up the RPM line until you reach the end of the compressor map and that's your absolute/uncorrected limit (for the compressor housing anyway). You can also see that if you drop the pressure a little say 2.3 - 2.35 from 3000-5000 your putting a lot less stress on the turbo and you'll be able to run a lot more timing there.

If you've not read it yet the Garrett page makes it a bit easier to plot points on the map i think:
https://www.turbobygarrett.com/turbo...compressor_map


Anyway, main thing you can take from the above is your boost won't be flat - you'll get a nice flat lump of boost in the middle of the revs, then taper as you approach the limit *or* maintain flatter boost through the higher revs and likely end up sacrificing timing to keep the knock monster away.

The Rig

iTrader: (13)

Cheers bud, as you say, i sacrifice timing to maintain the 1.35 to the redline ( 19 degrees at WOT full load from around 4k to 6k) but it pulls well and at 130 mph ( on track of course ) dont want much more timing lol