Twin turbo....twin Boost gauges?

[simonman]

i know the FD has twin turbo, i now know you can have 2 BOVs, can there actually be two boost gauges? one for turbo 1 and one for turbo 2??

[banned advertiser]

The turbos work independently so if you had 2 gauges only one would work at a time, but to answer your question no.
1st turbo comes in, then goes off as 2nd turbo kicks in.

[simonman]

thats strange. the boost gauge currently in the car just boosts straight to 0.8bar. id thought that there would be a bit of activity between swtiching from one turbo two another, like a slight drop.

[kev-yorks]

Has the car been modified in any way? Quite a lot of people mod the car to make the twins run in parallel instead of sequencial mode.
Kevin

[Martiny]

Actually, I have 2 gauges, while I try and resolve my boost problem.

1 gauge shows me the total boost from both turbos, like normal. The 2nd gauge is connect to the secondary turbo, right at the turbo housing. I can watch the 2nd turbo pre-spool, and then come on line. Once I fix it, the gauge will be redundant, though.

[Fish]

I always thought that the first turbo didnt spin down once the second came online. Thinking and my dont work well together anyway.

Fish

[iaint]

I always thought that the first turbo didnt spin down once the second came online. Thinking and my dont work well together anyway.

Fish

I think you're right as both tubbies are the same size (certainly on older cars). The second would have to be much larger to make up for the other going offline. The primary spinning down could explain the transition but I'd always put that down to the pressure drop as a whole section of the system is opened up...

[BlitzBoy]

Both turbos are online after 4500K in seq mode

[Martiny]

Fish, did you get that from my post? Sorry if it was misleading. First turbo stays on boost at low and high revs. - Poor first turbo! At least the secondary gets a rest now and then ! :-))

[Fish]

Martin no not you, Gary's post indicates that the first goes offline.

Iain, I thought the transition drop was due to the little flap/gate opening and the second not being fully spun up at that point.

Fish

[Martiny]

Ah, I see. Yes, Gary is not vorrect this time I'm afraid.

Its like this :
When revs are increasing....
1st Turbo up to 4.5k, 1st PLUS 2nd turbo after 4.5K

When revs are decreasing...

Both turbos from redline down to 3K, then only 1st turbo below 3K.

Fish, you are right about the transition, too. We feel a slight dip as the turbos are "added" together.

[ro284]

Martin, is there any way to avoid the Dip? holy grail i guess!
Bob

[Fish]

You can convert the turbo pack to non-sequential, this will smooth out the boost across the range.

The slight dip, is sadly the normal point where newbies (to FD's) get caught out, and has ended up in write off's.

Compared to the Supra's twins, they have a much smoother version of transition.

Fish

[Martiny]

ro 284, you can run both turbos all the time, called "non-sequential", but that lowers your boost under 4K, and it lowers it a lot at 2K, and you dont gain any extra boost above 4K.

Personally, I LOVE having that low down power.

Fish - a lot of people have said about how the 2nd Turbo catches them out, but its far, far smoother, than, say, your foot on the clutch pedal, or an auto changing gear. I think these people would have still lost it even without the transition .

When they say it "kicks in" thats misleading, too. It is much smoother than a "kick".

[allstaruk]

I belive you can also have the transition point smoothed out on a power FC when it is mapped.

[nikp]

When i took my FD to pip to have a boost issue sorted out, he somehow sorted out my transition too - it's now smooth.....unless my second turbo has stopped working, but i still pull 0.8 up to the red line. And it was always smooth, even when running back frm pip sorting it out. I don't know what he did though - he said he could sort something out - but he didn't say what it was!

[Martiny]

If only we knew what that trick was ! Are you on the standard ECU nik?

[nikp]

Are you on the standard ECU nik?

I was at the time - I'm not now.

I dunno - I'm tempted to phone pip up at some point and ask him, as I seem to be the only person he's done this for!? Maybe I'm imagining that he said it now? I'm starting to doubt myself now!!

I'm on an Apexi ECU, and thought i'd try and figure out if the second tubby is working last night, so i disabled the sequential control. I presume that means it'll just run the frist turbo, but seeing as i was only in commuter ville at the time, wasn't able to get a decent run to identify anything. However, boost peaked higher than it ever did at 0.9 bar, rather than the 0.8 it usually runs, so i got confused and stopped!