neuronbob

I tried something different yesterday. I've been using BP gas from the station around the corner from me for years. Once I emptied my gas tank this time around (and this time, I drove on fumes), I switched to Shell V-Power based on the Top Tier Gas recommendations--it was the only gas provider in my immediate area fitting the criteria.

Wouldn't you know it, the popping is almost gone! I expect it'll take another tankful to truly clear out the old gas, but the sound of near silence is bliss. Further, the car spools up more easily when I press on the gas. I figure I just had a tank of bad gas...come to think of it, this didn't start until the last time I filled up, which was about ten days ago, and that was several days after the exhaust was installed.

Hoping this is the solution!

dragonlord

I've never had the TL run good on BP gas. Shell premium and Speedway work best, Sunoco is all right. 10 days between fill-ups? I wish! Now that the exhaust and intake are done, that will change.

neuronbob

An anomaly, to be sure. I was off for two of those days and I played "garage queen" with the RL, and drove the heck out of our new Pilot.

dragonlord

Oh Oh! Soccer taxi!

gavine

Quick thought on the horsepower issue on the dyno......any chance the A/C compressor was on during the test? With all of the excitement of the test plus the fact that the RL doesn't "advertise" the fact that the A/C is on very well leads me to wonder if you didn't notice that the A/C was on.

That would rob a lot of horsepower from the engine, wouldn't it?

Touge

A/C on most cars takes away about 10-15whp on a dyno

neuronbob

Fair point, but under full acceleration in most modern cars power to the accessories is decreased, is it not, just as it is when the car is started?

As it happens, my climate control was on full automatic, and it was cool enough (48 degrees if I recall correctly) not to require the AC compressor, so I can't say for certain whether it was on.

Besides, the AC compressor alone wouldn't account for a result 20-30 hp less than expected.

Edit: Touge and I posted simultaneously....

gavine

In AUTO mode, the compressor is definitely ON. I'm not sure if the RL's compressor is a variable-load/variable stroke or an on/off type but either way, regardless of the outside temp, the compressor will run.

I wasn't aware that the compressor turned off at full throttle. If it does, that's great but I wouldn't think it would be set-up that way. What if you were on the Autobahn at full thottle on a hot day for an extended period?

Sorry to disappoint but I guess for your sake, as long as you had it on AUTO both times, your measured gain from the mode was still legit.

It's just that the total number on both tests is lower than it should be.

732xghost

iTrader: (1)

can believe those things loose that much power to the wheels.

miner

I can smell a Class Action Suit similar to what Mazda encountered with the RX-8. To advertise 290HP and to get the numbers you are posting is quite disturbing to me.

neuronbob

Good points about the AC.

So far, we have two 2G RLs dynoed on this site, and with similar stock results. Can't be just my car. Miner, 290 hp is at the flywheel and the losses can occur anywhere in the drivetrain after that. Given our n=2 results so far, it appears that there is 35% loss of power through the drivetrain.

I think others who are so inclined should dyno so we can get more datapoints.

In any case, that's one more thing the Honda engineers can work on for the 3G RL.

gavine

I'd bet both of you had your A/C on durning the dyno tests. Like I said before, it's not easy to tell whether or not it's on. I always double check after my wife drives because she hits the auto button and that turns-on the compressor, which is bad for power and gas mileage.

Ever drive a 4-cylinder car with the A/C on. It's amazingly sluggish. The RL is powerful enough that you can't tell it's on but it definitely puts a drag on the engine.

miner

I understand that 290 hp is at the flywheel and that there is loss through the powertrain BUT 35% is not normal - 15% LOSS IS NORMAL.

neuronbob

I certainly can't argue with that, gavine. It is hard to tell whether the AC compressor is on, and it probably was on. The dyno was done the same way both times, so the gain noted is still valid.

miner, your comment is why I'm asking for more data points . We have two cars with nearly the same results on AWD dynos, so I don't think my car has a significant problem. Well, I hope not, anyway. Just like in the scientific and medical world, replication of a result is as important as the original result. If five RLs have similar dyno results on varying (or even the same) machine, the issue is in the design of the drivetrain. IDK much about the RX8 case mentioned above. Did people figure out the true power by dynoing?

miner

Yes, the RX8 case was intiated when tuners started to dyno the cars. The HP discrepancy was much less than we are experiencing. Thanks for your efforts Bob.

http://consumeraffairs.com/news03/mazda_buyback.html

neuronbob

Wow.

You know, Honda usually UNDERSTATES their HP claims (only exception: changing to the new SAE standard). So the case of the RL is a bit unusual. Is it worth a class action, though? Who knows? The RL is not a sports car, so I can't see many people interested in that, but that's just my humble opinion. I'm certainly not ready to lawyer up over this. There's frankly not enough data.

Again, the only way to know whether there's a real issue is if other people go out and do stock dynos. I promise, they won't hurt your car!

Chas2

I am actually hoping to do a stock dyno in the summer and then try a pulley from Touge and dyno again. Will have to wait until July or August when things quiet down a bit. There is a place about 30 miles away in Manassas, VA that has a Dyno Dynamics AWD (2400 whp steady state) quad retarder loading dyno.

The pictures show cars being tested with the hood up and a huge fan being directed at the engine compartment.

neuronbob

I'm going to be in the Boston area at the end of the month for a conference. I plan to road trip it with the wife in the RL rather than flying--about a ten hour drive from here. Why bring this up?

http://www.dentsport.com/?p=189 Time for a second opinion! They have a Dyno Dynamics AWD dyno and boast of the airflow in the dyno room.

So how far is this from downtown Boston? Might actually do it.

dwboston

With no traffic, Norwood is about 20-30 minutes from downtown Boston. It's right off Rt 128/I-95, south of the Mass Pike (I-90).

How much does a dyno cost? I live about 30-40 minutes from there - if it's reasonable I could do it. I haven't done any performance mods to my RL (no exhaust, intake, etc) beyond the A-Spec suspension.

neuronbob

Thanks for the info, dwboston, and thanks for the offer to be an additional data point.

At Buschur, the dyno was $100. That covers a max of one hour. In my case, the runs were done so quickly that I only paid $50 before mods, and $50 after since I was having the parts installed there.

I'll call Dent in the next couple of days to see how much they charge. I hope I have time to do this, though the wife may not like having to be a "tuner chick" during the brief duration of the test.

gavine

Don't forget to turn-off the A/C this time.....PLEASE!

neuronbob

OK, I promise!

Edit: Just spoke to the good folks at Dent, explained our situation and this thread. The dyno costs $100 with AF and boost measurement (the latter is obviously not necessary on our cars) and I scheduled for the week of the conference. I promise (as usual) more pix and a full report.

A note: they use a 60k cubic feet/minute and a 30k cu ft/min fan with another 20k cu ft/min fan that can be focused where needed, so airflow doesn't seem to be an issue.

Touge

Thanks Bob, can't wait for your next update . I think you should be fine for the airflow. Most turbo cars are the one's that need the extra flow. I remember when we dyno'd the wrx, the intercooler when sprayed with water was evaporating almost instantly !. For the RL I'd suggest removing that plastic engine cover to help.

neuronbob

I just came back from the Dent Sport Garage in Norwood, MA. The link to their shop is above. They use a Dyno Dynamics AWD dynamometer.

AC and VSA were off, hood open, lots of cooling. Ambient temp was 66 degrees.

Max HP was 181 at 6000 rpm! Max torque was 172, at 3800 rpm. The torque curve was remarkably flat.

A-F ratio was steady between 10.5 and 11.

Definitely something funny about our drivetrain here. I think I like my original numbers better.

The dyno sheets will be posted when I return home in a few days.

Chas2

Wow, what is going on?! That is a pretty huge difference! Can there be that much loss in the drivetrain? And that is with your mods. I guess that it would be even less without.

miner

Is HP measured at both axles, and, if so, how? 181 hp is even more discouraging that your initial runs. With 15% drive train loss I would expect about 230-240 hp at the wheels. These mmeasurements (with mods) is approaching 35 - 40% loss. My RL does not feel at all like a 180 hp car. I am sure htese guys at the shops know what they are doing but I am completely confused by the outcome.

Jaysmith2000

There's no way this 4000lb car is being pushed around by 180hp at the wheels WITH modifications. Even without the mods this is too low. I'm going to check the Seattle area and get mine dyno'd....

neuronbob

Interestingly, I was told before the dyno that the Dyno Dynamics dynos read lower than Mustangs.

My experiment here is done. I've shown three things: a) It is probably not possible to get an accurate chassis dyno measurement on our car. This car doesn't feel like it's only putting 180 hp to the ground. b) different chassis dynos indeed measure differently. c) The best use of a chassis dyno is to measure gains for mods, and I encourage anyone considering adding power mods to get a pre-mod dyno first for the edification of the rest of us.

I'm not an automotive engineer, so I can only speculate that our drivetrain has something to do with these screwy results. I'm pretty sure the only way to accurately measure this engine's power other than at the flywheel, is to do what the Temple of VTEC did--make the car FWD temporarily.

I can tell you that after my mods, this car has more low end torque, proven in particularly this dyno as the torque peak is pulled down the power curve. Further, in third gear, the car pulls and pulls and pulls, up to above 90 mph. Despite the dyno findings, I can still recommend these mods.

If I opt for the pulley, I'll repeat.

Touge

Dyno dynamics has the lowest reading dyno's out there. Still I agree with the rest of you, this car is almost too smart for the dyno.

allykahn

iTrader: (1)

I am a little confused here and I apologize in advance for the following statements/questions.
From what I understand, hp is measured at the flywheel and wheel hp is calculated with a loss at a given percentage (15-20%). SO...

How can a car misplace over 100hp?
How can "making the car FWD" prove anything?
How can this car really be smarter than the dyno?

I remember a while back when we purchased our Volvo S70 T5 (236 hp) that the "R" cars were advertising 300hp, when in reality it was proved much lower by members in the R Forum. I can't remember the details but I could try to find out if you think it may shed some light.

neuronbob

Your questions are definitely appropriate as I had similar questions when I started the process.

It's not that the car "misplaces" 100 hp. There is always power loss through the drivetrain, especially in an AT car. The average drivetrain loss in an AT car is 15-20%. The drivetrain loss on this model appears to be 35%, a number supported by an AWD dyno manufacturer (Mustang). I agree with this as we now have two cars on this forum with similar (pre-mod) wheel horsepower. The number I got yesterday was on another brand of dyno that is "known" to read lower than the one I had my initial testing on.

I mentioned FWD because this is how the Temple of VTEC obtained a dyno on an RDX. Here's the link. The detached the driveshaft connecting to the rear wheels to accomplish this.

The reason we think the car is doing something to make the dyno less accurate is that the SH-AWD causes the torque on each wheel to vary second-to-second depending on traction available, etc. It has been postulated that on a dyno, the car experiences an "infinite slip" situation that causes the engine to put less power to the wheels. This would cause the dyno to read lower than expected.

Of course, the other possibility is that Honda has pulled a fast one on us, much as Mazda did with the early RX8, a possibility brought up by one poster in this thread.

I hope this helps a little.

allykahn

iTrader: (1)

Thanks for the video link. It was very helpful.

Benush

First Bob, thanks for everything that you have tried, but I have to tell you this story.

I was talking to one of my old racing buddies who fancies himself a true genius when it comes to knowing about all things performance.

I happened to tell him about all your work trying to dyno the car (pre Boston) and all the disappointing results. He said that what you really needed to do was find a ground level or maybe a below ground dyno (no idea what that is but he talked like I should know) and you needed to do a dyno run with one set of wheels on the dyno and the other end up on jack stands so the other wheels could run freely and then repeat with the other set of wheels on the dyno and the opposite end on jack stands in the air. yes, truly, that is what he said. When I tried to explain that the SH-AWD system had all these ways to compensate for tire slip, VSA and more stuff that I really don't know about or how it works, he said that by doing the two different runs and sending him the results he could easily determine the true HP of the car.

Anyway, I just thought I'd give you a chuckle.

neuronbob

Thank you, I needed just that sort of chuckle as I hit the road this morning back to Cleveland. And who's to say I'm not clueless? I certainly don't have a definite idea as to what's going on here.

I'm going to try one other experiment. I'm going to buy one of those Passport GT2 thingies to calculate HP. Car and Driver appeared to think it was pretty good for its cost in a comparo of mobile car performance devices recently.

Good thing about being a modern neurologist is that there's so much new stuff to learn, you never get out of that inquisitive mode, I guess.

Or maybe I should just buy a used Evo or WRX as a weekend car and use that as a project car.

BustedJack

Bob,
Great job on the dyno. I've always wondered how well a RL would do on a dyno. At 191whp from market advertisement of 300, there seemed to be a 36.33% loss of power and less in TQ. It goes to show that Acura hiked up the horsepower and may not necessarily be true to have 300HP.
The mods you've put in shows some significant HP gain at the crank, 13whp is a good amount for just intake and exhaust. This explains why the TL is much faster than the RL when my car was stock and ran against my neighbors back in 2005.
Keep in mind the RL is no slug, it's one of the most luxurious car I've ever ridden.

thanks for the info and good job!

neuronbob

I agree with you, Jack. If you take into account the 35% drivetrain power loss, that whp gain of 14 translates as much as 40 hp at the flywheel. And yes, I understand that it's not possible to be that accurate when converting whp to crank hp before people more technical than me jump in.

I'm catching up with work from my time out of town. I plan to post the curves for the second dyno soon (likely tomorrow).

RL06tech

Not to piss anyone off, but from just looking at the RL air intake it seems that the stock intake is a CAI already! The inlet is outside of the engine compartment.

CleanCL

iTrader: (4)

at WOT, the compressor shuts off. doesn't matter if A/C is on or not.

neuronbob

It's similar with the 3GTL, which Acura also billed as a "CAI", but the issue with that is that the cold air mixes with warm air from the engine at one point, as opposed to using a CAI with no addition of engine air. I am unsure whether the 2G RL's stock intake is similar in design to the 3G TL, but if it is, that would explain some of the HP gain in my dyno.

CleanCL, thanks for letting us know about that!

RL06tech

Maybe its all the cat back!