Tweaking the car last night and having a dabble at top end boost i got the boost to hit 1.4 bar from 3500 all the way to 6200 but i had to reduce timing from 21 to 19 as had a tap of knock at 6100, no bother so reduced timing to suit.

i noticed i had to reduce the timing at load level 54 (2 load points away from full) as this was where from 5800 the engine load started to lower to.

So my question, as engine load had started to taper off at 5800 even tho was hitting 1.4 bar still (engine load is usually 58 to 60) but was starting to taper to 55 is it worth lowering boost to say 1.2 and increasing timing or keeping as is (reduced timing ) and keeping the higher boost ?

Car didnt seem to run any worse for the higher boost, the TD05 is still within its capability at this level so too much heat wasnt an issue, well, it was as i had to lower timing but car still pulled great.

Just something to ponder over and see what peoples thoughts are ?

cheers

 

Interesting.
My thoughts would be to tapper off the boost at the top end,you're well past peak torque and I would guess at the top end of rpm you will be just blowing hot air with no power gains.

 

Totally agree with what your saying also, hence i thought id try the higher boost right to the redline and see if it changed anything, inlet temps were no higher than normal at that range , the TD05 is still capable of producing the 1.4 bar boost at that level (not so mu h just hot air )

i very very rarely get passed 6000 rpm in 5th gear lol so its not something i test very often but as i say i noticed engine load had tapered off quite a bit from the 58 to 60 at say 5500 to the 54 or so at 5800 onwards even tho was still hitting 1.4 bar , maybe thats showing the point at which boost should start tapering as engne load starts reducing (5800 rpm )

cheers

 

Could it be possible your intake temps are safe but charge temps get alot hotter ?

I want to get a gauge sorted on the I/C pipes to see the differences

 

Ive got my charge temp inside the silicone hose between throttle body and intercooler so it should register if the charge temps were increased , it is hard to monitor them tho precisley when you are concentrating on the road tho ha so they may of spiked and i didnt notice at that specific time etc

I was more intertested to see if anybody had done a run to redline at reduced timing and high boost compaed to increased timing and low boost , if 1 is more proven than the other .

All good intersting stuff tho

 

https://youtu.be/bw54_zeeiL8

worth watching

 

Hmm yeah slightly enlightening but the end answer was I guess whatever suits the car and driving style lol


Thing is when you run say 1.4 bar and then lower it near top end, unless im doing it wrong you can feel the drop in power/lack of "pull" on the car.


I used to drop to 1.2 after 5500 when running 1.3 bar and altho reliable ( even tho it would hardly be at this for long ) it felt flat compared to when on point with 1.4 earlier on etc

 

best way will be to run virtual dyno logs against each other, try a 4th gear run with flat boost and a 4th gear run with tapering boost but more ignition timing.

Assuming your charge temps aren't ramping sky high then the turbo is still happy to produce the airflow but as you can see from the drop in load the amount of air your getting at 1.4 bar up top isn't quite as fantastic as it could be so a back to back comparison is needed to see if there are actually any gains to be had. In the event that both runs are the same then I wouldn't bother with the additional boost - no point in pushing the turbo harder than you need too.

 

Yeah sound advice bud, will do a 4th gear run with the 2 maps but ive not had much luck with virtual dyno software, there doesnt seem to be a WRX to select for a 1995 model, the ones you can select seem to have different final drive ratios or gear ratios etc which throw it all out of whack.

I very rarely go passed 5500 in 5th gear so its a dilema / tuning area i rarely get into , cars tuned more for sprint boost than longevity/continuous of boost lol but it pondered to me once passed this area the sudden drop in boost compared to more timing doesnt seem to have the same in the seat feel to it as the continuous level at 1.4 bar

cheers all

cheers guys

 

I keep meaning to have a play with virtual dyno,I though you could input for a custom car,put your own gear ratio,weight etc?
I might be thinking of some other software tho? Lol

 

yeh you can create a custom vehicle with your own pre-set weight/drag/wheel size/gear ratios etc. and just use that. The reality of it is your not really worried about the actual numbers, just the difference between them so you can pretty much pick any car and compare the two runs to see which is better (assuming you have both runs using the same settings).

 

As above. A MAF sensor can show you whether you are flowing more air mass too (load will drop of course after peak torque but air mass should climb to around peak power), but even then you may find that the loss of efficiency from the ignition retard and fuel dumping required to prevent knock outweigh the extra airflow. Or you may find that it is not repeatable/suitable for heavy use.

Alternatively: If you are not scared at 6000 RPM, the turbo is too small.

 

Air flow is still strong at 6200 as maf voltage is st 4.98

As you say it's probably not a level I'd like to maintain for long and in all fairness never run long or hardly ever at 6k plus in 5th ! Ouch lol