thanx guys for helping me

 

top pic is the gm

 

thanx

 

so what is the one below

 

It says right on it

http://grimmspeed.com/

 

It's a MAC valve like AEM / etc use.

- Bryan

 

Which one is better?

 

Depends on the application an what level of boost you plan to use

 

Price:
GM > Grimm

evo guru's prefer the GM unit.

 

I like the GrimmSpeed unit myself, it just cost more $ then the GM.

 

Don't get the grimmspeed. It is a POS. I have tuned THREE of them and all three oscillate the boost under high load. I do not think that the MAC valve based GS can handle high boost conditions. It is just too slow to react properly. STAY AWAY.

There are ONLY two good 3-ports that work great on the EVO. 1. GM 3-port that now comes with the pnp harness. 2. The tactrix/gruppe-s/pierreburg (sp?) that comes with a pnp.

These two are EXCELLENT 3-ports. Do not waste your money on anything else.

 

Interesting about the boost oscillations. Are these relatively high frequency oscillations, say around 20 Hz, or are they more slow oscillations occuring closer to 1 Hz?

 

I agree with you and I saw the exact same boost oscillation.
I would say that under 22psi it work fine, at 25psi you have a little bit of oscillation but I tried 26 to 27psi and the boost is all over the place. You can really feel it in the car that it's not steady.

I've tried 4 units (Grimmspeed) and they all do the same.
I'll order a GM or a Tactrix to compare it with.

 

I did not log the frequency when it happens. It happens at the onset of peak boost. In a 4th gear pull it will oscillate the boost from 3300 rpm all the way to 4500 rpm. After that the boost will steady out. I have tuned A LOT of GM and tactrix/Gruppe-S/Pierburg 3-ports and NONE of them behaved that way. NONE. I have had THREE of these POS behave the same way.

The first one, I blamed on the BOV flutter, but when two other cars with the same 3-port behaved the same way, I knew it was the 3-port. On one of them I swapped the 3-port to the stock solenoid and the oscillating boost went away. The owner of the car noticed it right away.

PLEASE stay far away from this 3-port.

 

Thank you for confirming what I experienced. I thought I was going crazy at first. I am at old hand at tuning ECUboost, one of the earliest tuners to adopt it. I thought it was me at first, but as I saw three cars experience the same thing, I knew it was the 3-port.

Get the GM or tactrix, you will be much happier. I have used both of these 3-ports with great results.