Would you do more timing or boost ?

[gczarny]

here is the question , temps cooled down in my area to low 50's high 40 ' ( Illinois ) and I am getting ready to go to the strip for last time this season , I did some runs on the street ( still tunning my XFI after new build motor installed ) and I noticed that my tune timing even where is set to 18 deg. at 20 PSI it was logged at 21 deg , this is due to the fact that my XFI tune from Cal is adding more timing if the intake temps fall under 80 F ,they did fall to 74 F on these few runs sooooooo........I have 0 knock ,this is 93 octane tune only I am working on at this time so it looks like I could get some more power if I do what ???? turn up timing or use fixed timing and turn up boost , what's getting the JOB DONE MORE BETTER guys ,timing or boost I was reading here that smaller turbos react better to timing and bigger like mine like more boost , is that right for any octanes or we talking race fuel only ? and is it true that the outside air has to be in the 50's to make max power on turbo engine ?

 

[BlackBandit]

There's not a real simple answer to your question. I would say figure out (via math and then with small changes) the most efficient amount of boost to run and then add timing.

 

[gczarny]

There's not a real simple answer to your question. I would say figure out (via math and then with small changes) the most efficient amount of boost to run and then add timing.

well , here is the thing , I only used 93 with alky in the past or race gas on my build motors , the only time I used 93 octane gas only was right after I bought my FIRST 100% stock GN and I blew HG at 21 psi boost ( knock showing a lot ,still kept it to the floor ) , now I am trying to tune this build car /motor with very different set up again on 93 octane only , 20 psi with 21 deg. timing in todays temps show 0 deg.of knock so I would like to push it little bit more since my 76 turbo is not even waking up at this level but I can not do it on the street with my G force meter because I loose traction so it has to be done at the strip , just trying to find out which way is better to go with my set up if anybody tried it ,I know I might be close to the limits anyway just don't want to make 10 runs for nothing going wrong way , thanks

 

[Razor]

You need to monitor performance. Meaning typically its MPH at the track. Then make adjustments that yield more MPH(trap speed)

Some cars you can get 25 PSi and 14 degree's timing. But that doesnt make it faster than 21 PSI and 20 degree's timing.. used as illustration.

There are too many variables in play to say which way.

 

[gczarny]

You need to monitor performance. Meaning typically its MPH at the track. Then make adjustments that yield more MPH(trap speed)

Some cars you can get 25 PSi and 14 degree's timing. But that doesnt make it faster than 21 PSI and 20 degree's timing.. used as illustration.

There are too many variables in play to say which way.

well , I guess I just have to run it and find out that way , thanks

 

[bison]

Monitor your inlet air temps. If its not going up much with boost increases then run more boost. 26psi and 22.75 degrees on mine is about 800hp. The most timing id run is 24. I would run up to 30psi on this engine if i could get it that high. You can remove the timing being added for cooler temps if you want. I doubt Cal has it adding more than about 1*.

 

[3.8vsix]

Monitor your inlet air temps. If its not going up much with boost increases then run more boost. 26psi and 22.75 degrees on mine is about 800hp. The most timing id run is 24. I would run up to 30psi on this engine if i could get it that high. You can remove the timing being added for cooler temps if you want. I doubt Cal has it adding more than about 1*.

I have Cal's XFI program on my car also. I notice that he has at 32degs, 3.00 advance and at 64degs, it is at 2.00 advance then at 90degs he has 0. I was going over my log when I run it a couple of weeks ago and noticed that my target spark did not match my actual spark. I am glad I read this post, now I understand why my target spark did not match my actual spark at wot.:smile:

 

[gczarny]

Monitor your inlet air temps. If its not going up much with boost increases then run more boost. 26psi and 22.75 degrees on mine is about 800hp. The most timing id run is 24. I would run up to 30psi on this engine if i could get it that high. You can remove the timing being added for cooler temps if you want. I doubt Cal has it adding more than about 1*.

well ,the tune is adding 2 * between 90F and 64F , my runs showed drop to 74F than going back up to 80F , the timing I logged was as high as 21.25* ,that is from base 19.5* ....yes Cal's tune is 18 * at 240 Kpa ..... ,I already bumped to 19.5 * while playing with it , so it is about 1.75 * added , did not feel much difference on these street runs but ....at the dyno my car made 28 HP more just by adding 1 * of timing from 17 to 18 * at 20 psi boost , this is why I am so which way to go from here .thanks

 

[TBSS AWD]

Do Both And Add Methonal Injection.

 

[3.8vsix]

well ,the tune is adding 2 * between 90F and 64F , my runs showed drop to 74F than going back up to 80F , the timing I logged was as high as 21.25* ,that it from base 19 * ....yes Cal's tune is 18 * at 240 Kpa ..... ,I already bumped to to 19 * while playing with it , so it is about 1.25 * added , did not feel much difference on these street runs but ....at the dyno my car made 28 HP more just by adding 1 * of timing from 17 to 18 * at 20 psi boost , this is why I am so which way to go from here .thanks

I just check my base spark, at 240kpa he has mine at 21deg. Wander why there is such a differance? I am running pump gas and alky also. Seems to run great and not knock.

 

[gczarny]

I just check my base spark, at 240kpa he has mine at 21deg. Wander why there is such a differance? I am running pump gas and alky also. Seems to run great and not knock.

I do NOT have alky ON at this moment , this is just 93 0ctane only tune I am working on , Cal's tune was set at 18 * for 20 PSI , He told me it is safe tune and I am seeing 21* at 20 PSI and still no knock at all , I did use 0.060 " Cometics rathert then 0.040 " for this motor build , wonder how much more I can get out of this combo .

 

[GNVYUS 1]

So the first time around you blew the head gaskets with too much cylinder pressure and now you're asking if you should push more than 21 degrees of timing with 20psi on straight 93 octane?

Really, you want to go here again. You've got a killer tune and great inlet temps if on 93 octane you're able to run that cylinder pressure in a full weight GN. If I were you, I'd enjoy the knock free runs and leave the greed for the high octane/alky runs. From here I'd add more boost with that large of a turbo.

 

[bison]

my car made 28 HP more just by adding 1 * of timing from 17 to 18 * at 20 psi boost , this is why I am so which way to go from here .thanks

28hp average over a given range or peak? Adding 4psi boost i used over 15% more DC with six 83 lb/hr injectors at the same target. My alky would be feeding a higher % at the higher boost level too. Boost was worth way more than timing for me. Its not even close.

 

[gczarny]

28hp average over a given range or peak? Adding 4psi boost i used over 15% more DC with six 83 lb/hr injectors at the same target. My alky would be feeding a higher % at the higher boost level too. Boost was worth way more than timing for me. Its not even close.

it was a Dyno run so it was 28 HP in 4000 to 5700 RPM range with peak at 5400 RPM without changing anything but timing by 1 deg....... by the way ,when my HG went at 21 psi and 93 gas only it was on stock GN and I saw knock very clearly over 18 psi up all the time , just dam stock HG would not blow till I cranked it up to 21 psi ,it needed to blow so I had a reason for rebuild without my Wife questioning money spending on something that ain't broken if you know what I mean ,anyway this car is very different animal now with GN1 heads and Precision FMIC however I ran same combo on my Weber stroker short block and still was getting knock at 19 psi up so alky was turned on all the time after that but .....that car had stock ECM with MAF PRO and little bit less of FMIC , I really think today that tunning with Fast is a key to using your combo to the max potential ,so anyway ,blowing things up with what I am using today is out of the question ,got no reason for that car is finished the way I intended :smile: looks like now we talking boost over timing ,just wonder if i should let the tune to do it's timing adjustments based on IAT or changed it to fix timing and try boost only ?

 

[Phoneguy]

Sounds to me like you need to call Cal. Pretty sure he knows what he is doing with the FAST.

 

[bison]

Sounds to me like you need to call Cal. Pretty sure he knows what he is doing with the FAST.

Hes running Cals maps and its working well for him.

 

[Phoneguy]

Hes running Cals maps and its working well for him.

I know that he is running Cals maps that is why I suggested that he call him before making changes to the maps that he set up. I am sure there is a reason that Cal programmed it the way he did.

Bryan

 

[gczarny]

Sounds to me like you need to call Cal. Pretty sure he knows what he is doing with the FAST.

Just got back from little vacation at Door County WI Fall Festival , thanks guys for all the suggestions , looks like this week I will be eable to hit the strip
and test the ideas , will post some more after that , thanks