RHD M52/S52 ITB setup

[darbyfam]

Went to the dyno today with Brody from Miller Performance tuning from his office in Canada.



Here is a comparison of the last dyno in March of 2016 and today's dyno. What I take from this is that:


(1) you can't compare the two directly like apples to apples (we all knew that). The first dyno was in March on a much colder and less humid day. The tires I was running today were a bit taller than the ones I used last time.
(2) the previous dyno had always been questioned by those "in the know" because of the crazy torque numbers
(3) the ITBs and port and polish definitely made a change.


I am going to assume that the taller tire and weather conditions made (X) difference between the two sessions. Lets just say it's 10% (27 WHP/25TQ). Yes, this is a made up number with no scientific backing, but it's for explanation purposes only. If you take the assumption and apply it to the dyno graphs (increase today's results by 10% or reduce the last ones by the same number) you will more clearly see where the two graphs differ. The most glaring would be the HP/TQ loss between 3100 and 3700 RPMS (highly disappointing). This delta steadily decreased as the revs increase. At the top end, the delta is completely gone on the graph and if you apply the 10% correction factor, today's results would be more than the last dyno. Given all of this, I am taking away from this that the ITBs robbed me of a good bit of low-end HP/TQ and gained a slight bit of HP/TQ at the top end. Overall, I consider it a failed modification at this point because of this. Had I not lost so much HP/TQ dow low, I would have been much more satisfied.


I am hoping that upgrading to Megasquirt on going Alpha-N (no MAF) will help the situation some but I cannot believe that it will be able to make up that lost HP/TQ between 3100-3700 RPMs.


I am not terribly disappointed. I knew this was a possibility of happening but sometimes you have to be the first to do something just for the hell of it. Also, dyno graphs mean nothing for how I use my car. Lap times tell the tale. I will be back at NOLA on July 19th on the long track and will do an apples/apples comparison on what really matters.

[digger]

you could revert back to old setup and see if you get what you had back? this way you have a A-B-A test. there could be something else at play related to the issues you had.

ive done mods where i lose a bunch of torque and revert back to the old setup but it never brings back the torque and 10 years later i still wonder wtf happened.

the result is surprising, the difference in runner geometry length and area isnt that big enough to cause a 50ftlb loss imo and the specs on the runner length arent far from what they should be.

what do the hp overlays look like when you use roller speed in mph instead of rpm for horizontal axis? does it say the same thing sometimes the rpm pickup is wrong skewing torque

[CoMZ302]

Still have the VANOS? Any cam tuning?

Also, your dyno plot doesn't appear here.

[darbyfam]

The dyno was using roller speed vice RPM off the motor. With the vacuum setup, going back and forth is not that simple.

Still have VANOS and cam timing is TDC.

Dyno plot shows fine for me.

This trip to the dyno was not about getting everything out of it. It was mostly about getting a data point with the ITBs. The tuning isn't optimum (look at AFRs) the dyno setup wasn't optimum (we didn't even hook up a RPM lead). I suspect that the torque curve will flatten out a little once I get the MSPNP and DIYAUTOTUNE does the tuning. I don't expect to get back to a dyno plot like the red plot above (279whp/279TQ) but I do expect for things to be more clean and realistic.

[darbyfam]

I am reserving judgement on the ITBs (as should you) until I complete the ECU install and tuning. In hindsight, I probably shouldn't have even gone to the dyno in the current configuration as I knew we were not going to spend hours and hours trying to make it "right". As it was, I spent two hours on the dyno at hourly dyno costs just to get a look at where we were. It ended up being a bit of a disappointment and a lesson at the same time.

I will make my final determination after everything is tuned right and I get some laps on track. I am getting the ECU installed and tuned on a Thursday, going to Atlanta Motorsport Park on Friday and Barber on Saturday and Sunday. It's going to be a really good overall test of where the car is.

[darbyfam]

Took the car to DIYAUTOTUNE and had MS3PRO PNP installed on the car. Also spent some time on the dyno after install. Car ended up making 304WHP/257WTQ after tuning. The torque curve is very flat and the power extends significantly up the curve with the ITBs. This graph is in 40 hp/tq increments showing the uncorrected numbers.




During the MS3 install we did find that the VANOS and water temp sensor plugs were reversed so the previous dyno plot was without VANOS and without water temp input to the ECU.

After this latest tuning session, I have to say that the ITBs made a significant difference in the way the car feels and pulls. I am sure the MS3PRO helped a good bit as well but I would absolutely do it again.

[Bimmerman535i]

Took the car to DIYAUTOTUNE and had MS3PRO PNP installed on the car. Also spent some time on the dyno after install. Car ended up making 304WHP/257WTQ after tuning. The torque curve is very flat and the power extends significantly up the curve with the ITBs. This graph is in 50 hp/tq increments with the hp curve passing just above 300WHP.

During the MS3 install we did find that the VANOS and water temp sensor plugs were reversed so the previous dyno plot was without VANOS and without water temp input to the ECU.

After this latest tuning session, I have to say that the ITBs made a significant difference in the way the car feels and pulls. I am sure the MS3PRO helped a good bit as well but I would absolutely do it again.

Very interesting! What cams are you running?

I've swapped the oil pressure switch and VANOS plugs before...I couldn't figure out why the car felt weird until a friend caught the error and fixed it.

[darbyfam]

Very interesting! What cams are you running?

Sunbelt Stage 2.

[CoMZ302]

That's an amazing dyno plot. Congrats. I'd love to hear how it sounds.

I will say, you're giving up some RPMs at the top there. (Maybe next build) I'd switch to the solid lifters and run that thing up another 800RPM.

I gave up the VANOS to make ultimate power, and yours is making about 60 more RWHP at 3000 RPM than mine. Of course mine is a 2.8L so that's some of it. Near the top we're much closer; mine goes to 8K.

Congrats, that is fantastic.

[darbyfam]

Video clip of the post-tuning celebration

https://www.facebook.com/19937879725...1855972676268/

[e30polak]

Car could probably make more power taking it to 7500 based on the curve!

I'd be interested to see how these would do an a car with the VAC IP Dominator cams for comparison. I've never seen a Sunbelt Stage 2 car break 290whp, so those ITBs and the MS3 are definitely helping!

[darbyfam]

Car could probably make more power taking it to 7500 based on the curve!

I'd be interested to see how these would do an a car with the VAC IP Dominator cams for comparison. What fuel were you tuned on? What compression ratio? What headers and exhaust? I've never seen a Sunbelt Stage 2 car break 290whp, so those ITBs and the MS3 are definitely helping!

Tuned on 93 octane with stock compression (fully stock bottom end). Running Supersprint euro headers and a "custom" 3" exhaust consisting of a small resonator and a Flowmaster Hushpower Muffler.

[jakermac]

The torque curve is very flat and the power extends significantly up the curve with the ITBs. This graph is in 50 hp/tq increments with the hp curve passing just above 300WHP.

Is it possible that the plot is showing the uncorrected numbers in 40hp/ft-lb increments?

[darbyfam]

Is it possible that the plot is showing the uncorrected numbers in 40hp/ft-lb increments?

Yes. Sorry about the misinformation.

[jakermac]

[TXBDan]

Got damn. Congrats!

[agfx]

Wow that's amazing results! Congrats!

[RSwannabe]

Darbyfam,

Any update on how you like these ITB's a year later? And changes to tune or additional dyno charts you could share? The dyno chart from after the MS3 tune is not showing in this thread.