Dyno for our 03-04 M45 BEAST?

[auditech10]

Actually you get a loss from both, so like I said we are both right.Here read this:http://www.superstang.com/horsepower.htm

[SupraStar]

I read the article and there is NOTHING about horsepower loss from an independant rear suspension (IRS), which is what you said. And you'd really be stretching it to say the IRS is a part of the drivetrain. Is the IRS part of a drivetrain? Sort of...I mean it has a differential as does a solid rear end. And it has axles that ultimately drive the wheels. But when you talk about "IRS", you think suspension before "drivetrain". An IRS equipped car won't lose anymore or less HP than a solid rear end. (both car being in same mechanical condition, obviously)

I'm an auto engineer and used to live at the dyno. I have NEVER heard anyone claim (apart from you) that an IRS is responsible for HP loss. I HAVE seen IRS equipped cars wheel hop badly on a dyno and break driveshafts and axles though. No worries with the M45, as I don't think it could muster enough HP in stock form to cause wheel hop.....

At any rate, I guess we can agree to disagree.

[auditech10]

But you lose power with every moving part and flexible part, correct? Therefore, with an IRS which uses halfshafts which use CV joints compared to a solid rear that has no flexible joints/parts.Id like to see a comparison with two setups, one with IRS and one with solid with the same engine/trans combo and keeping gearing the same. I gaurantee there will be a difference, there has to be.Either way it doesnt matter, but the rear end IS part of the drive train and IS a part of the total loss of power from engine to the wheels.Cheers

[SupraStar]

But you lose power with every moving part and flexible part, correct? Therefore, with an IRS which uses halfshafts which use CV joints compared to a solid rear that has no flexible joints/parts.Id like to see a comparison with two setups, one with IRS and one with solid with the same engine/trans combo and keeping gearing the same. I gaurantee there will be a difference, there has to be.Either way it doesnt matter, but the rear end IS part of the drive train and IS a part of the total loss of power from engine to the wheels.Cheers

Excellent post, this one. These are the types of things that go through my head (and yours too it seems) all the time!

I've only been present for one dyno run which was more or less back to back with the same car WITH and WITHOUT an IRS. The Mustang Cobra guys were having a hard time launching their IRS cars, and when they did hook, driveshafts were twisting (like pretzels!) and halfshafts occasionally were breaking. The easy fix was to install a solid axle from the standard Mustang.

The most noticeable thing was the weight. The IRS was about 90 lbs more, IIRC. On the dyno run, the solid axle car DID make more RWHP, but it was about 3%. Nothing to write home about. You'd think it would be more considering the rotating mass (as you pointed out.) But in this case it wasn't.

Unfortunately, there aren't too many other cars that you can just swap in an IRS easily and quickly and compare "apples to apples" on the same dyno.

If you really want to know more, I could call a friend who works at Rousch and see what he says? Let me know, and I'll see what I can do to satisfy our curiosity.

Cheers.....

[auditech10]

There hasn't been a day in my life when I didn't learn something new. Why quit now?Although very slight, 3% is 3% right. Best Regards

[sr79labrat]

Any new numbers yet?

When you dyno make sure to find out what dyno you are dynoing on....

Cheers, KTW

[Ryansfishn]

I KNOW I'M LATE TO THE PARTY!!

BUT!!
I did a dyno run a little while ago (Feb 2014) on a DynoJet system they had setup on a trailer at a recent car show. Did mine for S&G, knowing I was expecting awful numbers like everyone says. I was HOPING for 250 (my friends and I even did a little overunder bet, and I lost) and when it came time, my numbers were 240.2hp and 279.7tq. On two runs, the second one being best.

I own a 2003 Infiniti M45, with a short ram intake (Spectre conical filter on a custom maf adapter tube) and the exhaust has had the cats (post O2 sensor) removed, as well as the resonators, and the stock axleback muffler removed. It's been converted to true dual exhaust as well, so the only thing I have left are the pre-O2 sensor cats, and my stock main muffler. Car also had 104,xxx miles on it when I did the run, and she's got 105,xxx now. Car has stock open differential, at (I think) 3:15? Don't quote me on that.

I heard the guy after the first run talking to the other guy, but I only heard him say one thing: "Torque converter". Kinda scared me, but I understand these transmissions LOVE SUCKING POWER. And I'd LOVE to get a spare diff case from another M45, and toss in the Z32 300ZX TT LSD internals in there. That brings it all the way up to a (this I DO know) 3.69 ratio.

ALL THAT ASIDE. This particular dyno said 240/280. So....yeah....Still pretty disappointed the transmission is sucking 100HP FROM ME.
I also don't really plan to do any performance anything to her other than MAYBE a different exhaust setup. If I were gonna buy a car for performance I would have gotten a G35S, and would have built it for boost, I bought this car for it's luxury properties and wanted a show car for stance/VIP. But like it was said, my BUTT DYNO says this car friggin moves. I love having some ricer come up to me, thinking, "lolluxurycar" and I take him for a walk.

[Double E]

Better than never stopping by!!

Where in the world do you live that lets you pass inspection that way? (a no inspect state?)

[myother45isalesbaer]

I am very late to the party. Never got the invitation.

But here is my 2 cents. The 340hp is rated under ideal conditions at the crank. To get 210 at the wheels is not bad. These are luxury sport sedans. My op is enjoy it for what it is and don't worry about the dyno or Q mile times. Get a different car if the later are you goals. Just my OP.