agreed about autox. I took my car for the first time to an event a few months ago. I was bogging all over the place. You do need low end torque or an econobox that hits higher revs at lower speeds. Those little honda hatches and toyota celicas were doing awesome in the range.

 

I tried non sequential just to see what the big deal was. I hated it... but on the upside I didn't have another boost issue after that so it certainly has its positives.

Now im single and I am 100% happy, as full boost comes on at 3300 rpms and im pushing a hell of a lot more air than the stockers.

 

this is why i leave the autox work to my miata the FD is for street and track day use. (we have a pretty big track here)

 

We still talking about cars?

 

yup!

 

ha!

 

Thing is, the supra has about the same curbweight as na M1A2 Abrahams tank, fully loaded.... The RX7 so much more light and nimble so it will feel much quicker, much faster than when tuning heavy cars.
You dont need nearly as much power in a 7 to keep up with a supra on the straights, and in corners, the 7 will walk all over the highwaybattlecruiser of a supra.

 

reverus, can i ask what cause the fire? Also what is this sequential/non-sequential thing everyone is talking about?...heard bout it before but not sure what it is...how it works...how it makes more power...??

 

Serious?

Short story is, sequential is the stock twin turbo setup of the rx7. The first turbo boosts 10 psi, then it drops to 8 psi during the transition where the second turbo kicks in, and then 10psi again when both spool.
Non sequential is removing the sequential hardware and setup, simplifying the vakuum setup and basically having the two turbos work as one, with a narrower max power band.

do a forum search for more info.

 

It only makes more power from around 3800 RPM to 4500 RPM after that it's all the same. The thing is that extra power band is only used when you first stomp on it. So if you shift at 8k then the revs don't drop below 4500 RPMs. So yeah what good is that? That is a question I asked myself when I first did it. And the lag oh the lag...

I will say this that 3800 RPM boost threshold is debatable as some people claim their threshold is much lower. If it's is true I don't know but I can tell you this: I live in southern ca where the majority of FD's are at, I've been in the game for 13 years and I have yet to see any different in real life or proof via the internet... I have asked several shops, friends (who are mechanics), and even Brian from BNR and they all say 3800 RPM's. Shoot even my own car that supposedly had all the right mods for quick spooling non-seq twins had a 3800 boost threshold. I even went as far as asking for a vid from a member who kept claiming 3500 RPMs on his non sequential twins. Of course he didn't deliver even after I posted my own single turbo boost response in order to entice him to do the same. So yeah very debatable indeed.

If you have a car that has a proper working sequential: LEAVE IT ALONE! The combination of boost lag and boost threshold null the "extra parallel" powerband benefit anyway. On a sequential car the boost is instant after 2900 RPMs. It's so responsive that the car feels like a powerful N/A car. IMO the only true reason to go non sequential is if you are running elevated boost levels and are of course having trouble keeping a constant boost response. That or you just got sick of repairing the sequentials.

 

Then you have missed out my friend. A modified Fd with properly functioning twins is a thing of beauty. It's a same that most Fd owners have never experienced the twins at there absolute best. I really do feel sorry for you guys.

Edit:

Too add, I know the twins are a pain to diag. I find it much easier to just remove the engine and check everything. This allows you to clean a ton of dirty parts and replace some gaskets. Now as for my own personal fd, I was fortunate to have a set that worked perfectly for my engines entire life.

 

this x1000.

While my car is a chore to drive, especially since i have the main cat so i dont get full boost til about 4500rpm, i have zero boost issues. Except that one time where i was spiking like crazy cause a line popped off the wastegate lol. Thank god i didnt kill my engine. lol I drove like that for about 500 miles too, trying to get into boost to see whats what and nothing happened thankfully.

If i had to do it all over, i would still stay non seq. Seq problems are a NIGHTMARE. Its not so much fixing the problem, its diagnosing it. And seq problems in our cars are really random. One day its working, the next its not. Too problematic.

 

Just wanted to clarify something here.

Poor mans non-sequential conversion: Welding/ holding open existing flapper doors

Proper non-sequential conversion: Removal of all flapper doors

Rich-mans non-sequential: A expensive modification performed to the twins and stock exhaust manifold by David Garfinkle. http://www.blackgto.com/RX7/turbos/garfinkle.htm

As for this non-sequential vs sequential debate, if you're looking to make the most power out of the twins (high boost) you have to go non-sequential. Removing the flapper doors increases flow to the turbos and allows for more power at higher boost pressures.