Ok, after reading a few threads something got me a bit confused.

Is Sequential when the turbo's come on at the same time or seperate?

If the turbo's do come on at the same time, what are the benefits? negatives?

Thanks

 

Sequential - First turbo comes online, then the transistion, and the both turbos are online. Hence the 10-8-10 boost pattern. Drawback? Can be a pain to troubleshoot if you have a boost related problem.

Non-Sequential - Both turbos come online at the same time, mimickng a single turbo setup. Drawback? Boost comes on later (i.e. lag).

 

Right - wot he said...

I went non-seq on my '95 when I had to replace the original turbos. I got a set of turbos, manifold and intake pipes from a guy on the email list which had the butterfly removed from the y-pipe, the turbo control flapper removed from the exhaust manifold and the pre-control flapper removed - basically the complete non-seq mod done permanently. (And done pretty nicely)

My observations were that the boost built much too slowly for my liking. Things started kicking in around 4k but it just didn't have the immediate get-up that the sequential setup does. I had the wastegate actuator vented by both the wastegate and pre-control solenoids which seemed to work best to control the max boost.

I've since put the original exhaust manifold and y-pipe back on, and different set of rebuilt turbos, without any mods, taking it back to the stock sequential setup and I vastly prefer it over the non-sequential... you get immediate boost and good get-up at much lower rpms.

Of course that's my opinion and I'm sure there are plently of folks happy with the non-sequential behaviour, just not me.

Simon.

 

There is an option on my PFC to turn it into Non-Seq.

Would that be the way to do it if I wanted to make it Seq.

 

Nope. The turbos aren't controlled by the PFC.

 

How do you know if your car is seq or non?

 

if its non seq it has lag up the ying yang and great midrange and high end power...

if its seq you will feel a kick at 4500 rpms when the second turbo comes on.

j