I was wondering how the Crawford plenum would work with a TT. Does it make it leaner? Do I have to re-tune the e-manage?

Does anybody have both?

Thanks,
Az

 

bldrz does. But that car is more than just TT.

 

Thanks for your prompt reply.

Did you guys do any EGT testing (6 EGT sensors on each exhaust runner) or any other testing on the plenum showing the advantages of having it over stock?

Thanks,
Az

 

We have not. I dont know what bldrz and his group has done, you might want to check with them.

I do know from what I have been told is the rear cylinders still have cooling issues and thus are more prone to problems. I have also been told that there are ways to help fix this issue. I am sure that information will be released soon enough.

 

I talked to boulder nissan about doing the FI on my Z and one thing they stressed was that the stock plenum and FI dont mix.

They mentioned the condition of the #5 and #6 cylinders on two motors they tore down for bottom end work both showed signs of lean conditions when running stock.
They stressed the importance of the crawford plenum when going fi be it SC or TT. My eye is on the new aps plenum though as it will be out soon and looks to be the best solution now!

 

The Crawford plenum and strut bar were installed on my Z last week. I put it on as a safety precaution prior to increasing boost with some custom maps from ACP. No dyno #s yet.

 

Squill, I also did talk to Boulder Nissan and to add to what you mentioned, they said that they lost some HP on the top end, and that they will change it to another type of intake.

KShep, thanks please keep us updated, because I'm also wanting to change the plenum for extra peace of mind

Az

 

Will do...I pick up the car tomorrow (Thur) and take it out of harms way (hurricane).

 

I have one on order from Doug.

 

Good deal...my core is on the way back to him now. 3300 miles of TLC. No issues with the strut bar, except whether to position a wiring harness above or underneath it. We chose above, I'll post up some pics later...leaving work to pick her up in a few minutes.

 

Sweet! So the strut bar fits the Greddy kit? Pics please...

 

Here they are...running out of time and light

 

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How would a Crawford plenum (more airflow to #5 and #6) eliminate a lean condition?

 

Well, the Crawford plenum does provide more air to #5 and #6. But it provides *much more* air to #1 and #2, which are the cylinders that are air starved by the stock plenum. (30% less air to #1 and #2 than to #5 and #6 with the stock plenum, almost perfectly equal distribution with the Crawford plenum.)

With the stock plenum, you have #1 and #2 running rich because they aren't getting enough air, #3 and #4 about right, and #5 and #6 very lean. With the Crawford plenum, all cylinders receive about the same amount of air, so the mixture is the same on all cylinders.

 

The whole idea behind the Crawford plenum is to equally distribute the airflow among all cylinders. If my memory services me right, Crawford claims that their design will equally distribute airflow to a less than 5% difference between all cylinders.

If you look at the stock plenum from the side, you will notice that cylinders #5 and #6 (at the back of the engine) will get more air than cylinders #1 and #2 (at the front of the engine) due to the fact that the stock plenum is slightly slanted towards the front restricting airflow.

Az

 

exactly. You even out the airflow thus eliminatig any cylinders running richer or leaner than the others.