V6 Twin Turbo - Turbo sizing.

[RedMist]

There are several twin turbo kits available for my V6, however I'm running a custom application which will require different turbo and intercooler placement. This negates most of the kit.
476 hp is available at 10.6psi on one of these kits using the stock V6 internals which should see my offroad buggy become reasonably rapid.

My problem is this, I'm not a compressed air man. I've never read turbo maps and half the turbo's I've seen dont have maps anyway.

I wondered if anyone could recommend a well priced ball bearing, steel turbo (as I'll run antilag) that should suit my purpose of bringing a 3.5 ltr v6 from 270 odd wheel HP at 10.3:1 CR to the mid 400's.

I want to run twin turbos and custom make up an intake manifold to ensure intake paths are as small as possible and exhaust routes short as can be created. Throttle response is a priority, its one of the reasons I dont want to decompress. If I'm heading down the wrong route and you believe that a single turbo application should yield better results then please tell me.

[strx7]

Personally i'd look at running a pair of TD05H's on it, Evo1-3 exhuast housing
they'd be good for somewhere in the vacinity of 650-700HP. with high compression they'd spool fairly quick. Fairly small turbo physical size wise so you'd have less issues fitting them in. easy to get parts for, easy to upgrade, relitively easy to source aswell

[FST4RD]

You would want 2 small 16g's if you were going down that path, but even then it would be kinda laggy.
The 2.5 legnums and that run 1 evo 4+ turbo with good results or 2 x TD04's of GSRs.

[barryogen]

From my limited reading on it, I would think that a pair of GT2560R(from Garrett or equivilent by Bazda) ought to take it to there quite happily, while spooling dame near instantly.

Failing that, a Pair of GT28RS if they're not big enough, although it may(will) not give the same response.

My post assumes you have lotsa cash and buying new.

[strx7]

You would want 2 small 16g's if you were going down that path, but even then it would be kinda laggy.
The 2.5 legnums and that run 1 evo 4+ turbo with good results or 2 x TD04's of GSRs.

what you have to remember is his nissan engine is a) larger capacity, and b) highish compression. BOTH equate to faster spool up

........

are you allowed to run water injection?

[RedMist]

are you allowed to run water injection?

Water injection is a bit of an issue. ALthough its not regulated out.

The new buggy is a single seater mid engine. Its got bugger all room to put a water tank. Its also adding complexity in an additional pump, lines, filter, injector. Considering the frequency with which fuel pumps fail due to impacts and high end vibration on offroaders I doubt a water injection pump would last very long.
I had considered going WTA as I will have two large manifolds sitting on top of the V however again I'm adding complexity and a pump or possibly two. So the plan is to run two fat intercoolers, one in each of the sidepods. And possibly place fans on the back end of each.

[RedMist]

Personally i'd look at running a pair of TD05H's on it, Evo1-3 exhuast housing
they'd be good for somewhere in the vacinity of 650-700HP. with high compression they'd spool fairly quick. Fairly small turbo physical size wise so you'd have less issues fitting them in. easy to get parts for, easy to upgrade, relitively easy to source aswell

The Fortin transaxle is rated at 1100hp on road, or about 400 offroad. Its probably about where I want to be in terms of power to be compeditive as well. The twin turbo kits offered, tend to max out around the 470 mark so thats where I'm heading. 650-700 is reasonably easily achieved with an engine build with low comp pistons, however its not where I want to head. I want the engine to be responsive off boost, and even more responsive on boost. the TD05'h are probably a little big.

[strx7]

400HP at the wheels or at the engine?
i was talking 650HP at the engine, i always talk engine HP as its the only truely reliable HP reading you'd get.

Remeber you'd be essientally running a pair of 3 cylinder 1750cc 10.3:1 compression engines. Has it got factory cams or higher spec, whats the n/a power & torque curves look like? what is the minimum RPM you're wanting boost from etc? I feel if you used turbo's off 1.8 engines you'll have instant boost and run outta puff up top. Remember 1.8 turbo engines generally run 8.5:1 compression or there abouts and 225 degree cams (or there abouts)

I'd personally love to put a pair of TD05H's on a cammed 2JZGE at 10:1 compression. I BELIEVE it'd be suprising how well they'd work and how early they'd spool.

[Lith]

You are probably switched on enough about your motor to fill this stuff out:

http://www.squirrelpf.com/turbocalc/index.php

I quite like the idea of a pair of GT2554Rs from what I can see of your setup and what you want. I reckon it'd almost be NA like in delivery, and your 450hp target will almost be difficult to not surpass - you'd likely to do it with very conservative boost.

http://www.boostxtreme.co.nz/product-range/turbo-chargers/garrett-gt2554r-471171-3.cfm

I believe those turbos are what people use on turbo kits for MX5s and the like, they have acceptable off boost behaviour etc on the 1.8litre... using a decent compression nicely breathing 3.5litre I suspect you will hardly experience "off boost" under any decent load level.

[RedMist]

The GT255r looks like a very suitable turbo. However I'm probably (dependant on response) going to run antilag. I dont really want a turbo that will costs lots to purchase and support.
I'm leaning towards a set of TD04's, but still need to do a tonne of research.

One thing of curiousity is how the hell I load balance the turbos? The LinkPlus G3 only supports one boost control solinoid.

[IH8TEC]

you could not run the link boost control? barry and myself have a really simple setup using a norgren pressure regulator. can mount it by your set so you can raise and lower the boost still. and run two equal length lines from each wastegate? possibly do that with the link solenoid also.

[Lith]

The GT255r looks like a very suitable turbo. However I'm probably (dependant on response) going to run antilag. I dont really want a turbo that will costs lots to purchase and support.
I'm leaning towards a set of TD04's, but still need to do a tonne of research.

One thing of curiousity is how the hell I load balance the turbos? The LinkPlus G3 only supports one boost control solinoid.

I very much doubt you'd need antilag though I guess I don't know exactly how you would be using it? Have you driven many turbo cars? Anything above 2000rpm and I'd imagine you'll have positive pressure if you have it under any load - such are the benefits of having small ball bearing turbos What rev range will you be operating in?

In terms of the "load balancing" of the turbos - I don't think you have to get toooo scientific on that kind of thing, especially if you aren't going for huge boost levels. Seeing as you are going to be doing a custom setup you can give the wastegates whatever pressure feed you want. Could be worth asking the 1JZGTE guys here how they set up their boost control, but I'd imagine you should be able to get away with it with one solenoid?

TD04s will work very well as well I'd imagine, definitely a fair bit cheaper. T25s are another that shouldn't be too bad.

[RedMist]

Offroading is all about instant throttle response. The VQ engine is a very good very lightweight engine, but appears to be a little light on HP to compete against the top offroaders in NZ. Antilag is all about keeping the turbos spooled while either jabbing the throttle (to promote the back end to come around), changing gears, or trailing throttle into a corner. Saying that, the TD04 I ran on my Rally GSR, wasnt too bad in regards to response... not perfect... but not bad. In regards to turbo history, its pretty limited. A 185 road car, a 205 road car, the 205 rally (not yet run) and the Mitsi GSR RS rally. But I havent completed much in regards to turbo modification before.... I'm very much a NA Man.
Stock limit on the VQ is 7.5k RPM. However the torque curves I've seen on the professional TT kits show power running off after 7k. Considering the Fortin its probably better I keep the power low. Lets say 3-7k RPM.
As stated I know little of turbos. However if one turbo boosts slightly higher than the other, with a collective solinoid won't it pull boost from both turbos? Its not exactly a nice situation as one turbo will always work harder than the other. Am I not correct?

The TD04H-15g or the TD05-14g look to suit the bill well, with one small issue, the packaging isnt very nice. Would be good to throw the turbos nice and neatly up against each bank. I have to grab one once the car lands and see how it'll place within the frame.

In regards to not running EBC I'm very scared of spike, especially as this engine will still be running the stock CR.

Just wanted to thank all that had responded, you have all given me new directions to investigate.

[bbq1988]

looked into superchargers for instant response?

[barryogen]

looked into superchargers for instant response?

for the curve, and wide band of power he is looking for it'd probably be very cost prohibitive to go to an SC.

[RedMist]

looked into superchargers for instant response?

for the curve, and wide band of power he is looking for it'd probably be very cost prohibitive to go to an SC.

Bingo.

There are several SC kits for the VQ, however they are expensive, and all dont appear to produce anything over 350hp.

[barryogen]

Bingo.

Does that mean I get a prize?

Can it be a ride in your car?

[bbq1988]

looked into superchargers for instant response?

for the curve, and wide band of power he is looking for it'd probably be very cost prohibitive to go to an SC.

Bingo.

There are several SC kits for the VQ, however they are expensive, and all dont appear to produce anything over 350hp.

Just a thought

[RedMist]

looked into superchargers for instant response?

for the curve, and wide band of power he is looking for it'd probably be very cost prohibitive to go to an SC.

Bingo.

There are several SC kits for the VQ, however they are expensive, and all dont appear to produce anything over 350hp.

Just a thought

It was a goodun, and its certainly got some benefits. But I'm just searching for that little bit more.

[RedMist]

There is possibly one more thing to consider. If I'm not compeditive, which I doubt, I'll decompress the engine, run a new transaxle, and upsize the turbos...
So far I'm considering
TD04H-15g
TD05-14g
and I really do like the boost map of the GT2554r, pity it seems expensive and not well supported... although again I'm no hairdryer man.