LexISguy

Quick question if for instance the primary cats were not installed, would you then gain more HP than with the cats, because of the less restriction? If so with an educated guess how much more power could you squeeze?

Joe Z

iTrader: (10)

Alex, I think you should read this below thread (again) from post #144 and forward.....

Independent DYNO Proven results by "Caymandive" - no BS here!!

^^ He has done a ton of Dyno pulls and pulls down the 1/4 mile track to back up his reaseach..


Joe Z

lobuxracer

iTrader: (2)

No, if you do the cats right, you'll not lose anything. The gains I saw were pretty tiny and I wouldn't call them significant. I'd call adding the cats a total win for everyone involved.

Random does good work. They've been around a long time building high performance cats.

Fapout

iTrader: (6)

Ummm not to argue with you because I realize you know a lot more about the IS-F than I do but doesn't this defy logic considering that torque is related to hp? HP=rpm x Tq(5252)

Are you saying that it reads a completely different toque curve thus modifying the hp numbers to a lower read than normal? I can only see that with some kind of inverted curve. Enlighten me please.

caymandive

iTrader: (2)

DynaPack dynos connect straight to the hub with the wheels off, DynoJets are inertia type roller dynos so I'm sure those two major differences have something to do with it.

Sorry I don't have an answer for you just my own personal observation.

Fapout

iTrader: (6)

I forgot dynapacks connected at the hub. Weird. I would think there would be more loss with dynojets since friction comes in to the equation. It's all good. All observations are welcomed!

JE

iTrader: (1)

Well to understand this you really need to understand what correction factor each dyno uses. Basically when a dyno is designed and built it is calibrated. The manufacturer comes up with a correction factor that is designed to account for these differences such as friction, drag or expansion of the roller as it heats up. These factors that can change from run to run are removed from the calculation by whatever this correction factor number is. I found a really good article that explains this stuff in depth. If I can find it I'll post the link. Google dyno correction factor and you will probably find more info than you want

darbs242

iTrader: (5)

James which dyno type do you think gives the best estimate to how much hp is really hitting the pavement? Rollers, would make the most sense to me.

Fapout

iTrader: (6)

I'd be curious to know this too. I guess this is important but at the same time irrelevant since the amount of HP difference between you and another car would be fixed no matter how it was my measured, not to mention that if your car does the quarter in 12.2 and it measured 350hp on one machine and 380hp on another, what's the point?

darbs242

iTrader: (5)

By the way wanted to let the JE crew know ive put almost 1200 miles on the car since i left with numerous drive cycles and still no CEL, glad I didn't throw in new o2 sensors, great job!

lobuxracer

iTrader: (2)

There's the indisputable truth. A dyno is a tool to measure a change. There are lots of things dynos do well, and a few they don't do well. Comparing different cars isn't one of the things they do really well.

At the end of the day, dyno numbers are bragging rights and nothing more. There are lots of guys with big dyno numbers who don't possess the skills to actually use the power their cars make. The biggest difference between cars and the most important part to mod will always be the nut behind the wheel.

darbs242

iTrader: (5)

Joe, have you considered offering the exhaust with cats, as shown?

JE

iTrader: (1)

Not sure which would be more close to real world wheel hp, it's unfortunately not that simple. I do however know why we chose the dynapack over all the other dyno's available and that was simply because they are the most sensitive and best for R&D testing. (in my opinion) I would also venture to say the most accurate (when measuring gains or changes) not neccessarily the most accurate at measuring actual wheel hp but showing minor dips or fluctuations in power throughout the dyno run. We have been able to accurately measure changes in spark plug gap and minor changes like this. Like the one guy said, it's all about what it does in the real world and the dyno is mearly a tool to help you maximize your potential.....the rest is bragging rights......and darbs, you my friend can definitely brag now!!

Joe Z

iTrader: (10)

Considering it adds another approx. $400 to the price tag.. Probably not...

An IS-F with the two OEM primary CATs still in place, will still pass the basic sniffer test..
(Visual will vary from inspection to inspection)

This solution of adding the Random Tech CAT's, is a great resolution for those IS-F's that plan to run the Sikky Headers..

Best Regards,

Joe Z

JE

iTrader: (1)

Darbs I just wanted to check back in with you and see how everything is running. No CELs? Everything still on point?