twin turbo setup

[ryanmac 0]

Hi all

I was offered today by a mate a twin turbo setup fro an rx7 he is breaking....I have not seen the actual turbos but was wondering if they would fit to the vr6 or is the space to tight between the engine and firewall.....I suspect it is a pretty big setup

Ryan

[CALICO 130]

You can get twin turbo's on an R32 but i guess it all depends on what manifold and how big the turbo's are if your having a manifold made you might be better off with the turbo's above it.

[yakuza racer 16]

twin turbo, you need the runners made differently. i did some research on them, 1 turbo per 3 cyl.

will see if i can find those diagrams

[craggsy 91]

If you google Hpa twin turbo they may have how they mount two turbos on the 32 to give yo an idea. Hardest bit I'd think will be downpipes

[michael5556 247]

Mk1 r32 twin turbo ftw.

[FishWick 21]

Mmmm, that is the sex ! :-)

Yep, pipework is the trickiest bit.

The kind of (small) turbos you'll be looking at for this may even have a 3 bolt flange, which could bolt straight onto each of the VR6's manifolds?

The RX7 won't use a pair of dustbin lids so they'll probably work OK. If you take into account 1.4 litres per turbo, then a pair of K03s from a 1.8T might also work well, or a couple of K04s for more top end clout.

[ryanmac 0]

I have been looking into this and although it looks tricky it looks like it could be worth a try. I would be looking at getting some smaller turbos as it's more acceleration and mid range than top end I am looking for. Hopefully if I find some turbos with 3 bolt fixings I will trial fit them against my existing manifolds.

[michael5556 247]

Sorry too be a buzz kill but if it's more acceleration you want ten you will have to watch gearbox and driveshafts....

[FishWick 21]

Aren't the K03 turbos 3 bolt fixing?

I like twin turbos. Less exhaust backing up causing a restriction and less lag than a big, single turbo. It's win win. The only downside as already said, is the build complexity. Plus I suppose if the motor grenades itself, you lose two turbos instead of one, lol

[ryanmac 0]

The ko3 turbo is a 3 bolt fixing so I am just trying to find the spacing between bolts to see if they would fit onto the stock exhaust manifold. I have seen on ebay.de the twin turbo manifolds but they are for the r32.

I was thinking a pair of ko3s turbos with a short runner intake, water injection and a fmic would give me the power I would want.

[RBPE 198]

A machine shop should be able to knock you up some conversion flanges pretty cheap but if you're doing it on the stock mani then they are going to be placed low. Induction/comp side to passenger like the lhd ones but they are situated higher and d-p needs to be shielded from brake cyl/servo., plus there could be some increased back-pressure due to the D-P's needing to twist a bit when they are low.

Less lag is a bit of a fallicy to be honest as the argument for less rotational inertia due to mass of turbine wheel is negated by the fact you have half the volume of gas flowing to them. For example; using a TT GT25R set up you have 49-53mm turbine inducer compared with a 68mm on a GT35R with twice the flow aimed at it. I'd say that the extra lag is negated by the fact the TT kits tend to use DBB turbo's, stock inlet mani with longer runners for more torque and I would have expected them to also have tested the I.D. of pipework until the best set-up was found with regards to flow, speed and swirl of gas.

You're also on about an SRIM which will shift the peak torque further up the rev range and not what the KO's really like. I have talked to someone who has done twin ko4's on Audi V6 and he said they were lag like a single on 1.8T but ran out of puff over 6k rpms so wouldn't again. With an SRIM you'll prob have a small power band.

Not sure what car, assume12v mk3? I'd get a T3 60-1 on 0.82, SPA mani and stock Inlet mani imo, you'll get 450hp at a bar or less and bit better on drivetrain, it's when you have grip they shred the boxes anyway..... just my 2p.

P.S. It sound slike you know the 13B produces huge amounts of exhaust gas too?

[ryanmac 0]

Cheers for the reply.....I am still looking at this. There is lots of reading out there.

There is a lot of sway towards the single turbo especially the setup you describe but what can I say bar its all about the looks...:-) only kidding it's all about the acceleration.

[FishWick 21]

Try and find out what spec turbos HGP use as they rather enjoy their twin turbo setups, both on 12 and 24V VR6s.

[RBPE 198]

They use the DBB GT25 based turbo's, usually either 2554's or 2560's.

You have to remember that at 97%VE (I worked it all out on 24v heads so probably a bit less for the 12v heads), you only need around 28-29psia (about 1 bar of boost) to hit nigh on 50lbs/min of flow (maybe 45+ with the 12v heads). With the ko3's pushing 20odd lb/min max you're going to be maxing them out at low boost.

The GT25 based one's will even max out at less than 1.5bar on well tuned VR6.

Here's some boost plots I did for the 24v running 97%VE in various capacities and 7k rpm max. I have all the info you need, from fuelling requirements to boost plots. I'll put it together and post it up, I just need to resize things and add more info.

http://s194.photobucket.com/albums/z252/bigady69/?action=view&current=7-3076r-boostplot.jpg

http://s194.photobucket.com/albums/z252/bigady69/?action=view&current=11-GTX3582R_boostplot-Copy.jpg

http://s194.photobucket.com/albums/z252/bigady69/?action=view&current=14-GT4094R_boostplot.jpg

On the above plots I did it at 3500rpms, 4500rpms and 7000rpms to give an idea of any surge issues. On a GT35R on 0.82a/r turbine you'll be looking at positive mani pressure at anything over 2000-2400rpms as an example.

[MaidenVR6 26]

My friend Erik has twin GT3071R on his 12V for over 5 years now. From 16-30 psi on E85:

H1GbyYK1VoE&feature=player_embedded

[spadam 7]

That car is epic

[FishWick 21]

They use the DBB GT25 based turbo's' date=' usually either 2554's or 2560's.

You have to remember that at 97%VE (I worked it all out on 24v heads so probably a bit less for the 12v heads), you only need around 28-29psia (about 1 bar of boost) to hit nigh on 50lbs/min of flow (maybe 45+ with the 12v heads). With the ko3's pushing 20odd lb/min max you're going to be maxing them out at low boost.

The GT25 based one's will even max out at less than 1.5bar on well tuned VR6.

Here's some boost plots I did for the 24v running 97%VE in various capacities and 7k rpm max. I have all the info you need, from fuelling requirements to boost plots. I'll put it together and post it up, I just need to resize things and add more info.

http://s194.photobucket.com/albums/z252/bigady69/?action=view¤t=7-3076r-boostplot.jpg

http://s194.photobucket.com/albums/z252/bigady69/?action=view¤t=11-GTX3582R_boostplot-Copy.jpg

http://s194.photobucket.com/albums/z252/bigady69/?action=view¤t=14-GT4094R_boostplot.jpg

On the above plots I did it at 3500rpms, 4500rpms and 7000rpms to give an idea of any surge issues. On a GT35R on 0.82a/r turbine you'll be looking at positive mani pressure at anything over 2000-2400rpms as an example.

[/quote']

Brilliant! Thanks for sharing that :-)

[bungy 2]

you only need around 28-29psia (about 1 bar of boost)

Loads of very useful information here but shouldn't that read 2 bar? The 24v engines use 4 lambda's and so i've considered a twin turbo set up to keep the 2 banks of cylinders seperate for fueling control but UM have done some clever things with mapping and single turbo setups.

[legvw 0]

He means atmospheric pressure plus boost pressure equals the 28/29psia.

[bungy 2]

He means atmospheric pressure plus boost pressure equals the 28/29psia.

ok. I've not seen it written like that before but makes sense.

[FishWick 21]

Yeah it's the same as KPA (Kilo Pascals Absolute), which is the pressure reference I use personally. Mainly because it's what VW use and therefore what I know best. It's also nicer to map because manifold pressure is manifold pressure, 1 - XXX. PSI tends to go into minus, or inHG, when you are not making boost which isn't so 'readable' when mapping, just a preference thing.

So 200KPA would in fact be 1 bar of boost seen on the gauge because 100KPA is the pressure of the earth's atmosphere, so boost is added on top of that. Which leads me nicely onto yet another pressure reference, which is: "psig" or PSI Gauge :-)

See again, KPA is the one size fits all measurement. PSI is pants :-)