D-Rob

Good morning, everyone!

I'm just swinging in to share some results we had over the weekend with finally being able to spend a bunch of time with the turbocharged K23A1 platform in the 2007-2011 Acura RDX on the dyno. This car doesn't really get a lot of love, despite being the only current turbocharged Honda available in the USA, and the potential that it holds for a fun driver.

We removed the propeller shaft that drives the rear wheels in order to test on our in-house DynaPack Evolution 3000 2WD dyno in front-wheel drive configuration.

This particular example was tested with only one of our custom intake arms (3" diameter, like many of the off-shelf aftermarket pieces, nothing special at all. This also keeps MAF scaling close to stock.); beyond the intake arm, the car is completely stock. We performed the tuning with a Hondata FlashPro unit.




The car has been running around on a simple street tune for a while, but we wanted to compare the engine in stages, so for initial testing yesterday we returned the ECU to stock. With the ECU on the OEM calibration, the tests produced a best of 189whp / 206wtq, with boost tapering to 8psi at redline. The stock power rating is 240hp / 260tq at the engine, giving us roughly a 20-22% drivetrain loss in FWD configuration on our machine.

Next, the "street tune" file was loaded. The street tune was also done by me using OEM-like timing table curves, and OEM-style VTC tables; we didn't want to get too crazy on the street without knowing how much to trust or distrust the OEM knock sensor sensitivity, so the goal was to minimize knock and up boost, essentially. With this calibration loaded, the results were 218whp / 241wtq, with boost fairly steady at 14psi falling to 13psi.

At this point, we took the liberty of completely reshaping the WOT Lambda Adjustment, ignition timing, and VTC target tables, and also making adjustments to the knock ignition limit/retard tables. Knock sensitivity was left alone, as we found it to be fairly accurate. From Honda (as well as Hondata), cam advance is very limited, with the majority of the calibration never advancing past 0deg (in boost, no cam advance is used). After a few pulls dialing in the new shapes of these tables, we found a BUNCH more torque down low, and fair gains everywhere else. With these adjustments, the results were 255whp / 317wtq, with peak boost of 16psi early on, with boost falling to 13psi up top.



Dotted red = Stock ECU tune
Solid red = Street tune
Solid pink = Final dyno tune

Here's a comparison of stock ECU calibration versus the final tuned version.



I would like to note that all tests were performed within 1.5 hours total of each other, with IAT's monitored closely to keep them consistent in the 120-130deg range. These cars are very sensitive to heat soak with the stock top-mount intercooler when dyno testing. Injector duty cycle was also very high; 97% with an 11.6AFR fuel mixture. Knock count was reduced to "0", also. With both the OEM Honda calibration, and the Hondata reflash, ignition timing is through the roof; they are constantly relying on the knock sensor pull a bunch of ignition timing. By rewriting the ignition tables completely, we have eliminated the over-retard required. Target boost was also turned up as high as the engine allowed; without removing exhaust restriction, no more boost can be made. Because of this, boost does waver a little, making the 'waves' in the torque curve.

I definitely want one now.

Thanks!

- Derek

Dark_Teg

Man those gains are huge! All that torque down low and AWD would make for a fun daily driver.

Andy8

How well do you think the transmission will hold up at these power levels in the long term? Also will the rear differential be able to hold that power long term?

LightningTeg

Front mount, downpipe, and some E85 hmmmm. What size is the turbo and this is through an auto right?

wantboost

iTrader: (2)

Just had to copy the whole post didn't you?

IIRC the OEM turbo is fairly small, after all it was sized for minimal lag and low/mid range torque production. Also remember the OEM injectors are 550cc (I think) so that limits any kind of gains using a 100% OEM setup and certainly isn't enough injector to run E85.

I'd be curious to see what it could do after eliminating the factory top mount intercooler, plastic bypass/blow off valve, airbox, small intercooler piping, and those horrible flexible couplers that like to expand under pressure.

After that I think the next step would be the fuel system and upgrading the factory turbo with at least a larger compressor wheel. Since the factory setup has the exhaust manifold and turbine housing cast as one piece (think R35, SRT4, 335i, etc) upgrading the factory turbo with larger wheels (how large depends on the physical size of the housings and how much material can safely be removed) would be the logical step before moving to an aftermarket manifold and turbo, not to mention the majority of owners looking for more power but not wanting to void tier warranty would likely go with upgrading the factory turbo, mainly for ease of installation and it still looks stock so most dealers wouldn't think twice.

ek9_beast

5 speed!!!!!!!!!!!!!!!!!!........... Auto lol. Yea there's unfortunately no manual option

In case you didn't catch that, it's a 5 speed auto trans so not sure what kinda torque they can hold

Andy8

[QUOTE=wantboost;50477480]Just had to copy the whole post didn't you?

I apologize I was on my mobile and didn't realize I did it until i posted. :-(

D-Rob

The stock injectors are 410cc, and like I said earlier, they're out of fuel at the 255whp level on gasoline.

I'm trying to talk the owner into a set of ID1000's and some E85.

I have no idea how the transmission/drivetrain parts are going to like this at all. My job is to make power.

wantboost

iTrader: (2)

I've found most of the current OEM automatics are fairly beefy. It will all come down to line pressure and how aggressively the trans tries to shift with the new power. Typically you can tweak these values with most domestic transmissions but I don't think Hondata can access transmissions yet.

D-Rob

Agreed.

And you're correct, Hondata gives us nothing as far as automatic transmission controls go.

My Cayenne Turbo experiences these line pressure difference woes; if it shifts at half throttle at the new peak torque, I get a flared shift. Fun stuff. Once again, I have control over the engine, and no control over the transmission parameters.

$amGD3

Good stuff!! Always interested in these cars, I wonder how the used car market pricing is like for em

wantboost

iTrader: (2)

If you have a scan tool and honda software you should be able to access the TCU via CANbus since it should all be linked in the newer cars. It's just a matter of breaking down the control module and finding values that can be modified.

If people have already cracked the new GM and Ford transmissions I find it highly unlikely that we as a collective couldn't figure out the Honda ones. Unless they use some goofy software, code, and complicated protocols only the Japaese love to use just for the sake of being difficult.

Of course there always the good old manual method. If I could find one of those trans affordably in a scrapyard somewhere I would tear it down and see if there's a way to easily shim the line pressure valve body/bypass and other things like that. There still has to be some form of mechanical control as a secondary should the fancy electronics take a dump.

D-Rob

Just a quick update on this:

The car on the street tune previously ran a best of 15.0 @ 89mph.

Here is the latest, with just the dyno tune. We are very close to the stock turbo 1/4 mile record, with probably the least amount of modifications.



We're going to make a catless downpipe/midpipe combo for it, and toss some ID1000's in for some E85, and see if we can crack a solid 13.XX @ 1XXmph.

LightningTeg

Yesssss

Dark_Teg

Faster then my Trailblazer SS....not bad for just a tune.

Geis

It's funny because when I first got into boost and researched it and whatnot i was always thinking 'well wtf buy an OEM turbo setup (on say a hot hatch) when you plan on modifying the car, I would much rather build my own off an na variant '
Then I realized just how much power and how good of a curve the factory setups can have with such simple modifications like fuel system, exhaust and intake.
Just saw a vid the other day of a stock evo(8 or 9?) making a good amount over 400whp with just new intercooler/piping, injectors pump and exhaust (on e85 of course)
Ridiculous spool for the power he was making

wantboost

iTrader: (2)

I'm not sure how much more the stock turbo has left to offer. I can't find much about it in the way of wheel sizes to make a determination.

D-Rob

Another update on this car:

The customer decided to toss a DW65c fuel pump and a set of Injector Dynamics 1,000cc injectors in the car, and we retuned on 93oct again, and on E85. The figures on 93oct were a little lower than the last time we tested, but within 10whp or so. As you can see, E85 helped it out a ton down low (where we were able to up the boost and bump ignition). Up top, the car still won't make any more boost (presumably from exhaust restrictions with the stock downpipe/cats/exhaust).

Solid lines are E85, dotted are 93oct.


Fearing the transmission wouldn't like all that torque, we turned it down to 340wtq or so.

Friday night, he took the car to the drag strip, and broke the RDX stock-turbocharger record, first by running a 13.7 @ 98mph, followed by a 13.68 @ 99mph (his second pass was actually against a Jeep SRT-8, for comparison). The quickest/fastest RDX known has gone 13.67 @ 101mph, with a billet turbo/full exhaust, so I think we've got that covered on the stock turbo after some exhaust modification finally.

wantboost

iTrader: (2)

You're making me want an rdx to daily lol. What are they selling for these days?

jdmunlimited1

How much does something like this cost? Where is your shop located? When can you do this to mine?

boosted98acura

There is no intercooler piping on these. It's turbo-coupler-intercooler-coupler-throttle body. The coupler isn't doing any expanding. And the exhaust manifold and turbo are two separate pieces

wantboost

iTrader: (2)

The turbine housing and manifold are cast as one piece. Obviously the turbocharger isn't permanently attached.

I didn't know that about the intercooler though. Is there any sort of heat shielding underneath the core? It doesn't look like there's a very large air gap between the bottom of the core and the valve cover. Makes you wonder just how efficient it is even at factory boost pressures

boosted98acura

Uh no. The exhaust manifold is aluminum that's water cooled. Everything is separate. There's no heatshielding under the intercooler. It will be changed out for a a2w intercooler before spring.

This is my car btw.

wantboost

iTrader: (2)

I need photos of this exhaust manifold lol. In the press release photos it appeared to be a one piece assembly.

I would also think moving to a different intake manifold would help. They had to come up with a very convoluted design to accommodate the top mount intercooler.

wantboost

iTrader: (2)

After a quick search it's coming back to me now. These had that "variable flow" turbine housing which is basically a housing with two different volute sizes separated by a flapper valve.

That would help explain the massive torque these things make down lol.