Non-sequential or simplified sequential for exclusive track use?
 

Hello there,

I know this has been beaten to death but I read a lot of threads and most people still drive their cars on the street. My FD will be a pure track car, so it will only see rpms above 4k.

Since my engine is out at the moment for a rebuild, I definitley will touch the rats nest and in my opinion, it would be stupid to make a full hose job leaving the sequential system the way it is. So the least I want to do for simplification is the simplified non-sequential mod. But I also thought about going non-sequential (full, so including the removal of the flapper in the manifold) for the following reasons:
- most amount of simplification
- better exhaust flow (removed flapper)
- higher potential for further tuning

The car already has the following mods:
- HKS downpipe
- High-Flow cat
- Tanabe muffler
- presumably bigger injectors
- Blitz ECU

With that mods, I only got 10psi at max, with a strange pattern of 10-15-9, with the 15 psi only being there for a split second, badly leaning out the mixture. (I have to say though, the compression was pretty bad on the rear rotor, only 60psi at the lowest)
I'm planning on fitting a boost controller or Megasquirt 2 when the car goes back together, hoping for higher boost, maybe 12-13 psi.

So, without having to worry about lag below 4000 rpm, would it than be a good idea to make the propper non-sequential conversion now (And by the way, is there a good write-up for that? On all the old threads, the links don't work anymore)? Or would you advise me to only do the simplified sequential conversion?

You can make the twins work like non sequential on the Apexi pfc
Unit , change turbo transition to 2000rpm

You can have the best of both worlds .

Sequ and non seque

You will need to have the data logit unit to do this .

Cheers

I don't have a PFC and I'm not planning on getting one. But of course, if I go the route Megasquirt 2, I have to go non-sequential.

Apexi does the lot like factory , very user friendly

This is the setting for non sequential on the data logit .

the fuck you say? no you don't. i run them seq on my FC engine with the stock FC ECU.

Sequential. Fix your solenoid issues and you won't regret it. Drove a non-sequential FD and it was awful, but I guess if I really think about it on the track you will hardly notice the difference since you will keep the RPMS above 4,000 most of the time anyway.

Having driven both in anger (and both on the stock ECU) the sequential is faster on a technical course, as the primary turbo comes on boost quicker exiting corners.

The non-sequential car, required some odd footwork to keep the throttle slightly open under brakes in a corner, in order to keep building boost to then get out of the corner without lag.

This is the first I've heard of simplified sequential. Does it work as well as the stock rats nest? I would have to think there is a way to do it...

Now thats the kind of answer I was looking for, thank you! Would you say that is on courses, where the rpms drop below 4000 even in second gear? Most courses I drive on have corners with a minimum speed of around 60km/h (37mph), in my current tracktool, a Ford Probe 24V, I rarely see rpms below 4000 or 4500.

I've run simplified sequential for 7+ years on the track without issue. Just make sure your solenoids are tested and working appropriately. Plus, unless you're always running the same track, you will certainly run into situations where you'll dip below 4krpm. Your example of 37mph you could lug 3rd to be smoother.

Sounds like you need to figure out your computer/boost controller situation though, you don't want to spike to 15psi regularly. Also, expect your "high flow cat" to likely not make it very long on the track.