JB4 and Cobb Stage2 Dyno Testing..

[Mike@N54Tuning.com]

I know there has been a lot of interest recently in comparing the output and performance of the JB4 when compared to the new kid on the block (COBB) so BMS went over to the dyno and did some testing, so I thought I would share the results with community as its very topical.

Hey guys,

Headed back to the dyno to retest the Stage2 maps. Since last round I've added CPE downpipes and an OEM N55 midpipe to the car. It's still running the stock intercooler and 135i muffler back, still on 93 octane, etc.

The main purpose was just to test the JB4 map 2 vs. the Cobb Stage2 map. But while it was strapped down for kicks I tested the Cobb Stage2+ map and did a few runs working on a JB4 map 6 to test some "more aggressive" type JB4 settings.

As last time I have tons of data to sort though but as a general rule the Cobb ran more boost, more fuel, and less advance compared to the JB4. The Stage2+ map is definitely much more aggressive with a peak of 18.5psi compared to JB4 map 2's peak of only 14.5psi, but the JB4 runs a lot more advance and is actually very close in terms of power output from 5000rpm+. The range you'll be operating in during a race.

The JB4 map 6 is just something I was playing around with. I was able to get the boost and advance close to where I wanted it but didn't have time to work on the fueling end. So for the moment it's just a work in progress. But, it was very competitive in terms of power output.

[1-2MANY]

Hasn't this already been posted before?

[LateralG'z]

Cobb has much better AFR than JB. I think I would be worried to JB on my car

[Mike@N54Tuning.com]

Originally Posted by LateralG'z

Cobb has much better AFR than JB. I think I would be worried to JB on my car

The Cobb runs much more boost down low with less advance to make its torque, so it needs to run a richer AFR. The JB4 on the other hand runs less boost and more advance (which is more efficient) and thus runs a leaner AFR. This is a direct injection motor so the old rules don't really apply and running too rich down low at lower boost levels just wastes gas. Keep in mind 7500+ cars have been running the same basic boost/AFR/advance pump gas curve over the past four years with zero related issues.

The JB4 map 6 runs above are custom tuned are being dialed in. Those require more fuel for the boost levels being used and are under development.

These are Stage2 maps with downpipes. The last round of testing was on Stage1 maps with factory downpipes.

Mike

[thebigragu99]

Clueless people post about tuning with no experience what so ever.I'll bet ,Almost 97% off these people never had a Turbo car before.The rules change with direct injection,the fuel Burns more positive then negative therefore the afr characteristics change completely .I love how Cobb comes on the scene with all this hype ,and still makes less power.I want to see Some runs,Cobb stage 2 FBo vs jb4 Fbo.My money is on the jb4 ,advanced wins races not sO much boost.There needs to be a good balance in the 2 ratios .

Mike how long for this new map 6?

[Tony135]

Terry is doing some good stuff. I was there when he was dynoing the first time.

[Mike@N54Tuning.com]

Originally Posted by thebigragu99

Clueless people post about tuning with no experience what so ever.I'll bet ,Almost 97% off these people never had a Turbo car before.The rules change with direct injection,the fuel Burns more positive then negative therefore the afr characteristics change completely .I love how Cobb comes on the scene with all this hype ,and still makes less power.I want to see Some runs,Cobb stage 2 FBo vs jb4 Fbo.My money is on the jb4 ,advanced wins races not sO much boost.There needs to be a good balance in the 2 ratios .

Mike how long for this new map 6?

Shouldn't be too long but no firm ETA. Working on some cool things as well

Mike