Cellerator

I was reading an article about how some cars have 2 turbo systems in the car and i was wondering if it would be in any way possible to have a small turbo and a large turbo so that maybe we could get a bigger boost?

Roddimus Prime

That's not exactly how a twin turbo set up works but YES, Wagner Motorsports is building a twin turbo P5 as we speak. He has already made the manifold and has both turbos assembled. The motor is out of the car and getting all new forged internals. It will also run the AEM ems. Lok for it to be finished later this year.

Prote-J

Yeah, the boosts don't add. Only twin turbo setup I know of that used different sized turbos was the early 90's 911 Turbos. They used a smaller turbo for lower rpms to spool faster, and a larger turbo that came in later.

THEGOLDPRO

they must be some small *** turbos, like the turbos they run in motorcycles.

Arghman

Don't forget the last Rx-7 mazda made...Those had a really small turbo that kicked in at like 1200 RPM or something, then carried you up to like 2800 or 3200 RPM where the bigger one came in and kicked your ***

Prote-J

Thanks... I did forget that one!

Roddimus Prime

you guys have it wrong....there are not two different sized turbos. Also the FD twin turbo is a sequential twin, it doesn't work like you guys think.

The turbos on Andrews P5 will be smallER but not small....Same flow rates as the GT28RBB, one will be trimmed a .42 trim and the other a super 60. Each turbo will be fed off a pair of cylinders. This provide a bt more lag than a traditonal set-up but the advantage of different trims is that one turbo will build boost early while the other builds it later on. His car will be VERY fast and I doubt any single turbo car will catch it anytime soon.

The FD's sequential turbo has two turbos of EQUAL size and TRIM mounted butt-to-butt with each other. What happens is that one turbo is being spooled by the exhaust gas to 10psi. At about 4psi there is a butterfly (similar to a wastegate) that slowly start to open and allow the exhaust gas to pre-spool the second turbo. Once the first turbo hits 10psi the second is on about 7psi. You notice a slight tug around 4200rpms where the switch over is but the power is VERY linear and dare I say perfect.

I hope that clears up some stuff for you guys.

Cellerator

yea, thx
I was wondering b/c i havnt heard of any companies making a twin turbo for our car until u mentioned Wagner Motorsports was doing one.

Roddimus Prime

yeah, I doubt you'll see any others due to the high cost. This will be a show winning project car that I'm sure will be a great billboard for Wagner.

Cellerator

ahh, so would the gains be as much as one from HiBoost or higher? and how much would it all cost for it to be done? just an idea at the moment after reading sumthing on how superchargers and turbochargers differ.

Roddimus Prime

You'd have to understand that Andy is building this as an all-out race/show car. He is having the head P&P'd, RACE Turbo cams, forged shortblock, full AEM stand alone EMS....etc..

Wagner expects 400+hp and I don't think thats too much to ask from the turbo's they've got planned. You'd be surprised how flexible the AEM is when it can go from a mild street tune to a full out race job like this with a few keystrokes.

p.s. for those doubters, Wagner has a single turbo Evo on pump gas with the AEM making 554whp. Both engines having same displacement whats so hard to believe?

Cellerator

i dont think its hard to believe and i think it would b awesome to hav a twinturbo for our car if it's within the range of how much our car is worth when we bought it. I dont want to spend more than what the car is worth.

Roddimus Prime

well the forged shortblock is $2100....I'd imagine the turbo's costing about $500 a piece...so you're looking at almost $4K off the jump.

VagaBond-X

yup basically what roddimus said about the FD is right

the turboes are exactly the same size.....just different trim levels...this allows the first turbo to spool very fast, to give u some nice bottom end power.... it spools to 10psi, then switches over to the second turbo.... at this switch over point u notice the boost drops to about 8psi,, but then u feel that tug liek roddimus explained as the second turbo comes online... and then the second turbo spools upto 10psi
that is why they say the boost pattern on an FD is 10-8-10
10 (first turbo) - 8 (switch over point) - 10 (second turbo)
yeah but the FD turbo system is very complicated and alot of plumbing is required to make this system... so many vacuum lines..... just trying to troubleshoot can be very hard.... let alone re-doing ure vacuum lines, thats a nightmare

also mazda does have another seqeuntial system with actual different sized turboes...
the mazda cosmo (3 rotor (20B))

same sequential system as above... except it uses one HT-12 (same turboes as the FD uses)
this is the primary turbo
and a HT-15, as the secondary turbo....

despite the numbers the HT-15 is smaller than the HT-12, and the STOCK 20Bs secondary is not there for performance, just to keep the boost going, as the cosmo was not a performance car (even tho it has a WIKID engine, the awesome 20B)