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Full tune of 68HTA, KSTech 73 MAF, Racer X FMIC and DW750s


LittleBlueGT

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This will detail all of my experiences tuning my latest round of mods. Hopefully this will be beneficial for many out there, and maybe the odd self tuner will have some good advice for me as well.

 

My car before this round of mods (only mods relevant to tuning) are:

 

-AEM CAI

-APS turbo inlet

-AVO380 turbo

-Perrin TMIC

-HFS-5 alky system

-JDM TGV deletes

-Perrin ELH

-Grimmspeed UP w/ 38mm EWG (V-band, recirc to DP)

-TBE

-Base map is a modded COBB base (w/ Romraider) and RT overlay is via ST

 

Today I put in DW850 cc/min injectors. Previously I had stock injectors.

 

Stock latency (in COBB talk, and RR):

 

http://i248.photobucket.com/albums/gg194/littlebluegt/STlatency.jpghttp://i248.photobucket.com/albums/gg194/littlebluegt/Enginuitylatency.jpg

 

You can see that COBB uses something different then ms (maybe ECU direct value). To convert ST latency to ms simply multiply by .64.

 

RR injector flow scale was 520.59 cc/min ST was 5201. This one is an inverse relationship. To convert cc/min into COBB scaling take 2707589 and divide by cc/min.

 

Even though the OEM flow scaling was 520 cc/min, my injectors where flow tested by DW to be about 539 cc/min. Link to details on OEM injectors flow tested. I never did change the scaling in the ECU, as the intake scaling seemed to work perfect. (and maybe we don't completely understand everything that is going on the ECU)

 

My DW850s where tested at 867 cc/min. I did the math and plugged in 3123 into ST. Car didn't like it that much, but it soon trimmed itself out. I ran the inj tab in RR today, and this is the result:

 

http://i248.photobucket.com/albums/gg194/littlebluegt/InjtabSep120091.jpg

 

As you can see (at least with the MAF scaling I was using with OEM injectors) I needed to plug in a lower flow scaling for them to work better. I will be updating how the scaling goes tomorrow. For now I will try the suggested 806 cc/min setting (COBB talk = 3359) and I will leave the latency where it is at for now. (I have a theory about latency, but will share it later)

 

What other changes did I make:

 

Seeing as the stock injectors where about 60% the size of the DW850s, I did a blanket 40% reduction in these tables (all from RR):

 

-Per Injector Primary fuel offset additive (A, B, C, D) I don't know if this is correct, but it is what I did.

-tip-in enrichment

-minimum tip-in enrichment activation

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Some other info:

 

My last few LVs are as follows (LTFT): (keep in mind I rarely flash my ECU, just RT maps, so my trims aren't reset to 0 very often)

 

A

B

C

D

 

-4.70

0.30

-0.50

0.00

 

-4.90

0.30

-0.70

0.00

 

0.70

-0.80

0.60

0.40

 

-0.20

-0.80

0.60

0.40

 

-4.60

-0.80

0.10

0.40

 

-4.60

-0.80

0.10

0.40

 

-3.20

0.20

-0.40

-0.60

 

-2.20

0.20

-0.20

-0.60

 

-1.00

0.70

0.20

-0.40

 

-4.30

1.40

-0.40

-0.80

 

As you can see my trims are pretty constant, and pretty stinkin close. I am pretty sure I will have to recalibrate after the injectors are done. Either way, I will have to do it when I put in the K&N intake.

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Interesting, I will follow along as I'm a newb self tuner.

 

Just curious what made you decide to switch from AVO380 to the HTA68?

 

With 450 cc/min (and indicated 12:1 AFR) of alky I couldn't see the need for bigger injectors.:lol:

 

Seriously, I was able to get about 42 lb/min of airflow out of the AVO380, and I have seen logs (took a stinkin lot of searching, and bugging people) and heard from ones I trust (like Infamous1) that I can get about 46+ lbs/min out of the HTA68.

 

I also have that fancy DIY TMIC on the way (details to follow).

 

It also seemed that the spool of the HTA68 was on par, or very close to the VF series turbos, which is about 200 rpm better then my AVO. I really hope the spool is better, but so far all of the STIs I log locally spool worse then my AVO380, so we will see.

 

I am very sad that it is not a bb turbo, as I really don't want the turbo to die a death due to insufficient oiling, but I will try to prevent that by taking out the banjo filter, and ensuring I have no oil restrictions. In the end, I would have paid more for the same thing, but with a Garret centre cartridge, but it does not exist, yet.

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Good stuff..I never realized you were on stock injectors with the AVO?!

 

Yea, only ran WG boost on pump tune (95% IDC), which I never used. Then on alky I was at about 90% IDC.

 

I didn't need 850s, but maybe, just maybe we will get E85 some day.

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The scatter on your IPW plot is unusually high.

 

I don't know how to respond to that. I know it was running very lean in the upper rpm ranges, and wouldn't even run smooth. It was just a really quick plot to get things in the ball-park. I will do a longer run tonight.

 

Do you use the inj tab, or do you have a better tool?

 

I will also re-iterate (cause I don't think I made it that clear before):

 

stock set-up:

-running inj tab showed my latency to be pretty close, but it said scalar should be about 510 cc/min or even less. Scalar was 520 cc/min, but DW said it was 539. FWIW LTFTs where basically identical with the OEM injectors I had when I bought the car, vs the OEM ones I got from DW that were cleaned and flow tested.

 

now with DW850s:

-running injector tab says 806 cc/min, but DW says 867

 

the difference in both cases is about 6-7%

 

I am not sure why the difference, if others have seen the same (probably not too many run inj tab on stock injectors), and how I should proceed.

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Loaded the changes in for the drive home from work:

 

http://i248.photobucket.com/albums/gg194/littlebluegt/injtab2.jpg

 

Just a very quick analysis.

 

I changed the inj scalar, and I also changed the latencies across the board down by 3%. I have seen some people change latency a flat amount on all columns. I picked 14 volts (as that is what the car was running at. Figured that -0.05 ms was about 3% lower, then changed then by that amount.

 

Tomorrow I will have a nice long drive to examine the changes.

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I have very low confidence in the scaling and latency numbers provided by the injector tab. It gave me a widely varying numbers for the same injectors and MAF scaling - the only thing I did between tests was change the scaling and latency values in the tune.

 

It's useful to verify that the scatter plot makes a straight line, but I think that the actual scaling and latency are best set by AF learning values and WBO2 readings.

 

When I change latency, I scale them all by the same percentage. I'm not convinced this is correct, but it appears to my intuition and I haven't heard any better ideas. :)

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I have very low confidence in the scaling and latency numbers provided by the injector tab. It gave me a widely varying numbers for the same injectors and MAF scaling - the only thing I did between tests was change the scaling and latency values in the tune.

 

It's useful to verify that the scatter plot makes a straight line, but I think that the actual scaling and latency are best set by AF learning values and WBO2 readings.

 

When I change latency, I scale them all by the same percentage. I'm not convinced this is correct, but it appears to my intuition and I haven't heard any better ideas. :)

 

I have heard others say they also have low confidence in it. All I know is that I had extremely consistent results using it on stock injectors. (+/- 2 cc/min, +/- 0.10 ms latency). Of course I also had a MAF scale that was extremely consistent. (Anally so)

 

So far it seems that the results I am getting are equaling the results I had with stock injectors. I will see when I get a longer drive in.

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Why are you still using ST and RR? Do you feel tuning on the road that the RT maps give you that much of an advantage?

 

 

I like ST much better, in fact, I would likely buy it again when I get a new STI.

 

1) every time you load in a new map with RR the ECU is reset, therefore learning has to happen again from scratch, and the biggest problem, the stupid AVCS takes a few minutes to figure itself out (log AVCS next time after a new flash, it will be at 0 for a while) Sooooo, you want to do back to back AVCS runs, OS tuning is a royal pain to get it right, whereas I can do two pulls within about 1 min (different maps)

 

2) flashing a RT map is safer IMO, less chance of bricking an ECU (not that it is a huge deal, but still worth mentioning)

 

3) I have the PLX WB, it works with AP, but not RR. Two shops I have talked to used innovative in the past and hated it, soo many problems, they then switched to PLX and have not looked back. My PLX WB works great, and I plan to continue using it.

 

With ST you really need RR (and ECU flash) to get all the base map parameters right.

 

On all of the ATR maps I have seen, they are good on their own, RR has a few extra parameters, but then ATR has some RR doesn't have. All the ones I consider important are in both RR and ATR.

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I have heard others say they also have low confidence in it. All I know is that I had extremely consistent results using it on stock injectors. (+/- 2 cc/min, +/- 0.10 ms latency). Of course I also had a MAF scale that was extremely consistent. (Anally so)

 

So far it seems that the results I am getting are equaling the results I had with stock injectors. I will see when I get a longer drive in.

 

I was dialing in a set of pretty much unknown injectors, and the fuel tab's estimate of their flow rate varied from around 700 to 900 depending on where I had the scaling and latency set. I was not tweaking the MAF scale around that time. The really puzzling thing is that the scatter plots looked like a straight thin line, which made me want to believe the results... but eventually I gave up.

 

After a while I just set the scaling at 816 (what my injectors supposed to be) and tuned the MAF around it.

 

I can see how it might work better if you had 100% confidence in your MAF scaling in the first place. I'm curious how this goes for you.

 

I never noticed your post about testing the stock injectors until now, but it's interesting. It might explain why my MAF scaling came out a few percent higher than yours when we had the same intake.

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Let me know what latency and scale settings you end up with on the DW850's. I played with both a these for a little while, got things somewhat close and just left them. I'm curious whether you come up with better values than I have. I also have a bit of an idle issue with these injectors that bothers me every once in a while.

 

On the HTA68 front, I'm curious as to your results as well. 46lbs/min is higher than I'd expect out of the turbo, and am curious to see what you can get.

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I did three different (long driving) inj tab runs today. I did get weird results. 667 cc/min, 900 cc/min, along with a normal 817 cc/min.:spin:

 

I am starting to go with NSFW idea of using the LTFTs.

 

I will post up my results tomorrow.

 

I also am getting a bit of a weird idle issue. It is not as stable on/off ac like it used to be.

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