Testing of the JCW Exhaust and Intake on ALTA's GP!

This can also be found on our site here!

We’re at it again proving more ALTA PARTS! One question we always wanted to answer was “Do the ALTA parts make more HP than the JCW parts?”. We get asked this a lot as customers are torn between parts they can get at the dealer, and aftermarket parts from us. Our selling points used to revolve around the prices of JCW parts vs. ALTA. Now we have another angle! We can now say ALTA parts WILL make more power than the JCW, at a fraction of the cost. What more can you ask for!

The car we started with was a newly purchased 2006 Mini Cooper S w/ JCW GP package. For those that do not know, this is highest rated HP of any Mini Cooper produced to date (214hp and 184ft-lbs). While this a rare car, (only 415 were allocated to the US) we still had plans to modify it, and make it better.

First off a little history of Mini S’s on our dyno. With a 15% pulley, intake, and catback we would see around 190-195WHP. This is very typical and we have seen with many other Mini S’s. The GP’s averaged runs were under 180WHP, and while these are the highest rated HP Mini’s ever made, the 180 is pretty close to what we would expect it to make (using a 15% drivetrain loss, and 215 engine HP). So naturally getting to that HP should be easy (even with the GP’s bigger than 15% pulley) with our intake and catback installed.

The first step in our quest to prove we make more power is installing the Intake hose. We see about 5whp on regular Mini S’s with 15% pulleys, so I would expect similar on the JCW/GP packages. Sure enough it was pretty close to that. The gains with this part were at the upper RPMs where the stock hose becomes a restriction.



With 4whp gained from just the hose, things were looking good! Now for the part that we have all wondered about making more power than the ALTA Intake. The JCW intake! For those who do not know, the JCW intake uses a slightly different air box than the normal Cooper S. 2 things make it very different, one it uses a cone type filter (although still paper??) and it has a vacuum actuated flap at the back to allow more air to get into the box. The flap is a good way to add power, and not add noise. While the ALTA intake definitely adds some cool Supercharger Wine to you car, the customers that want to keep it quiet may stick with the JCW just for that reason. But we now have another reason or two to buy ours over the JCW.

Reason number one. Cost! The JCW intake system costs well over $400 where as the ALTA intake costs about $260. While more money means more POWER/better materials/cooler looks, in this case, we can prove that 2 of those features don’t work. Which leads to reason number two, More POWER! While the results are not the 12-15WHP we see on a stock Mini Cooper S, the 7WHP, and 6ft-lbs of torque is definitely a repeatable and accurate gain over the JCW intake system. Also this makes me wonder what kind of power the JCW intake makes on over the stock Air box on a Cooper S?? Hmmmmm…………….



So far we are on a high with our gains over the JCW intake system! Next up is another JCW part people buy before they buy our part. The Catback exhaust!! Looking at the exhaust there are a few things to take note of. It uses 2.25” diameter tubing, and were it splits into 2 mufflers it goes to 1.3” tubing. The ALTA exhaust uses 2.5” plumbing through out with no split. So bigger should make more power?? The weight of the JCW system was 40.8lbs, were as the ALTA system is 28.0 lbs. So our save a bit of weight over the JCW, which you would expect with the single sided system. So onto the dyno test. This test was also done back to back, and the car was left on the dyno between run sets.



So while 5WHP and 5ft-lbs isn’t a huge gain, it is more HP than the JCW system, which is supposed to be an upgrade from stock. We see about 12WHP on a 15% pulley car, going to our 2.5” exhaust, so we can conclude that the JCW exhaust might make about 6-7WHP. The exhaust system prices online vary quiet a bit anywhere from $1000 to $800, where ours is $300-$100 less expensive. From this testing of the catback exhausts, we now have 3 things that make our system better than the JCW. Cost, weight, and HP!



This is the final gain we saw with replacing the JCW intake and catback, with an ALTA cold air intake, and catback exhaust. If you are trying to eek out that last bit of power from your JCW packaged car, here is an easy way to get 10WHP. Also if you are thinking of buying JCW parts vs. the ALTA parts, you will see about 10WHP and 10ft-lbs more torque along with seeing more money in your pocket, from overall part costs, and shipping costs.

We have a few more tests we will be doing with our GP in the upcoming weeks, one of those is the ALTA PnP ECU! Be on the look out!!

 

Now this is the kind of product anouncement that we all love !

Great job Adam

Will you be offering a custom dyno tune for the Unichip buyers?

 

I'm curious of your choice of gear ratios there. The GP uses the same gearbox as the 05+ MCS, which has a 4th gear ratio of 4.615. You're number is 4.591 which would actually elevate the HP and Torque numbers slightly.

This isn't the first time you posted dyno plots with incorrect ratios either. Back when you posted the information about the water injection system the ratio was also incorrect there.

So I'm curious, why are you using numbers that don't match the published specs of the gearbox?

 

CmdrVimes
Stuck in Reverse <---

^ What the...? ^

 

If they use the same ratio for all tests, the relative gains are still there...
and, they could have included a screen shot without the input data if they really wanted to be sneaky.

dan

 

I understand that. However, with the ratio they have used for the Alta vs JCW intake test it elevates the torque numbers by approximately 1 ft/lb. While that's not that significant of a difference it still doesn't answer my question.

The gear ratios are published and easily available to anyone who bothers to search for them. So why, given that, do they insist of using a ratio that is different from the published number?

 

Good stuff.

Another dyno comparison I'd be pretty interested in (though I'm not expecting Alta to do it for me ) is the Alta CAI vs. JCW CAI with aftermarket filter. My gut feeling is that the heavy paper JCW filter is the bottleneck in that system... a fair number of JCW owners (self included) run the K&N, UNI or AMSoil filters instead, all of which seem to breathe better... My theory is that the JCW intake with an aftermarket filter would be much closer to Alta performance (especially if you run the Alta hose, like me. But I'd love to see this proven or dis-proven...

 

The way most all dynos are setup is by a relationship of speed to rpm. This creates an internally programed gear ratio. While your ratio number is correct, when we setup the dyno, we used BIM-COM and looked at the RPM. When the dyno and RPMS are correct, it generates its own ratio. While the number can be off a bit, its the same ratio from run to run. The changes in TQ, and WHP are still shown, and still prove that the parts work.

With the potential of constantly changing gear ratios with different years, or models, this is also the best way to setup from car to car. This creates one less way for someone to enter completely the wrong ratio for a different model or year of car. This would have a much worse effect on the overall numbers.

With the Dynapack we can enter an actual number in the unit. Many many other dynos, can't. They only rely on the tach and dyno sync method, which works perfectly fine from run to run as the ratio never changes.

So like we have said many times, its not the peak numbers, or the overall numbers, its the difference between the runs. IF we made our dyno read engine HP, the numbers would be very high, but the difference when installing parts would still be there. That is what is important to look at.

Again, we don't hide anything, there is no trickery, if our parts did nothing, we probably would have shown the changes are minimal, but that our parts are still less expensive.

Good point, and in the future, maybe we will, but again, the overall change is still there. If we enter the correct number, then we wouldn't be talking about this, and we would be talking about the gains.

Not a bad idea, but we do not have one of those to test. I would leave it up to them, to prove their own JCW drop in filter. BUT, while the filter is a hold up, the tube showed great gains, so a combination may work. But there are 2 things that still hold up the JCW intake compare to ours. Forgetting the filter for a moment, the "flap" on the JCW, is still pretty small. Also the stock rubber breather (part that goes from airbox, to plastic wall) hole is very very small. And on our GP, it was blocked off! Even if you unblock it, and leave the "flap" open the whole time, its still not that big of an area to get fresh air into the box.

But either way, the JCW does fit the customer who wants it nice and quiet. Our intake makes more power, but it is louder. I like the louder!

 

Hey thanks Jeff for clearing up any concerns and really great data!

Also, back to the intake, I must make a similar point. If you want quiet then the JCW box, (possible new ALTA replacement filter jeff and I are working on) and the ALTA inlet tube would be the best combination.

Thanks again folks!

 

Very interesting and good write-up. I am just wondering how much larger is your intake hose vs stock diameter. Are there other logical reasons why it made more HP? I am assuming its smoother inner lining creates better flow & air velocity? Looks like it will be my next mod.

 

The ALTA hose is 2.75"ID (stock is 2.5-ish) and a bit smoother. While its only a few HP, its a great way to get a bit more from your intake, and add some color under the hood.