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Oggie
23-07-2008, 01:55 AM
I have done a search on the net and i seen some discussions but no real details..

SO...

whats the main benifits of going from twin to single? also is it overly hard to do?

pros vs cons please.

mever mind i found the thread for the 1st g8 single turbo lol time to read it :D http://www.clubvr4.com/forum/showthread.php?t=27710&highlight=single+turbo

mods feel free to delete or lock

bradc
23-07-2008, 06:18 AM
single cons:

long piping
hot engine bay
lag
inefficient
horrible ugly piping

single pros:
cheap

reverse them for the twin cons and pros

Subaru ETA
23-07-2008, 07:12 AM
in mikes car there isnt that much lag..i mean yes there is more lag then the std set up but not as much as i expected.

when it comes under boost tho, you are are pinned back in your set right up to the red line

Gly
23-07-2008, 07:32 AM
single cons:
long piping


depends how its done, but its not too bad.


single cons:
hot engine bay


no worse than the twins,


single cons:
lag


depends what turbo you use.


single cons:
inefficient


compared to???...


single cons:
horrible ugly piping


it can be done nicely, with time and effort.
the twin pipeing isnt exactly pretty


single cons:
single pros:
cheap


easier rebuilds/servicing
easier to get one big single in rather than 2 mid sized units
**** factor/cool factor is greater



twin cons...

just as hard if not more difficult to set up,
space/size limits, just as much pipe work to be done.
2x as many turbos to break. and harder to service/rebuild

twin pros...

its still twin turbo :P

bradc
23-07-2008, 10:24 AM
I linked to the APS website a while ago when they compared their Single setup to their Twin setup on a 350Z, they stated that the single kit is capable of flowing the same, but it has 500rpm more lag and that it always will be like that on a V6 due to the increased length in exhaust piping as well as the extra inertia of a single large turbine.

Ohh and Mike's engine bay is a LOT hotter than any other VR-4!

valmes
23-07-2008, 11:32 AM
Again?

valmes
23-07-2008, 11:33 AM
V6, V8 - Twins
I4, I6 - Single

Wodjno
23-07-2008, 12:42 PM
V6, V8 - Twins
I4, I6 - Single

What you trying to say VAL :speechles

























































:D

valmes
23-07-2008, 12:57 PM
Babelfish it! /pan :D :D :D

Wodjno
23-07-2008, 01:50 PM
Babelfish it! /pan :D :D :D

V6, V8 - близнецы I4, I6 - определяют
:D :D :D :D :D :D :D :D :D :D :D :D :D :D :D

Turbo_Steve
23-07-2008, 04:34 PM
V6, V8 - Twins
I4, I6 - Single

I agree...but I'm curious: what's your logic, dude?

Wodjno
23-07-2008, 04:40 PM
I agree...but I'm curious: what's your logic, dude?

I would say because of length of pipe to supply the Tubs..

Inline - all off 1 bank supplying 1 Tub.. Short..

V- Tub off each bank.. Short


1 tub supplied by to banks means lengthening the supply pipe..

2 tubs supplied by 1 bank means more pipeage and more work !!

I'm prolly totally wrong /pan But thats my fix on it /rally

Turbo_Steve
23-07-2008, 04:46 PM
That's partly my thinking, as well as pulse timing and so on. Also, with an I4 or I6 you're a lot more likely to be able to set it up "twinscroll" as opposed to a single exducer runnel.

Complicated business, turbo sizing, though.

Wodjno
23-07-2008, 04:53 PM
That's partly my thinking, as well as pulse timing and so on. Also, with an I4 or I6 you're a lot more likely to be able to set it up "twinscroll" as opposed to a single exducer runnel.

Complicated business, turbo sizing, though.

Would it be possible to fit 2 x VGT's to the VR4 ? Or is there more involved than just slapping them on :D

bradc
23-07-2008, 08:00 PM
Yeah wodj has it! On an I6 (read skyline) it is easy to make it single if you want to, the turbo can be nice and close to the exhaust manifold. But Nissan still made the GT-R with twin turbos because they knew it would spool better.

Nissan are smart, Mitsi are smart :D How many HIGH performance V6's can you think of with single turbos? Most have twins, and even some I6's have twins, including the new BMW I6 3.0 twin turbo engine featured in the 135i and 335i amongst others.

Turbo_Steve
23-07-2008, 10:05 PM
I figured it was something like that.
Interestingly, the 300ZX effectively has two engines linked at the crank: Two exhausts, turbos, intercoolers, throttle bodies, inlet manifolds, dumpvalves, EGR, recirc everything.

Yet by the time they're producing the GTR, they've gone for a pair of ceramics on an inline 6 with sequential loading,

And then we get the NEW GTR, which is a V8 with twin turbos, one per bank, intercoolers etc. i suspect there is no "best" way: just different charecteristics.

bradc
23-07-2008, 10:14 PM
the turbos on a GTR were never sequential, and the new gtr is a v6 :)

Wodjno
23-07-2008, 10:30 PM
the turbos on a GTR were never sequential, and the new gtr is a v6 :)

Yup /yes

A Lil ole 3.8 V6 Twin Turbo :D

Looks like Mitzy got it right the 1st time round with the VR4 /rally

bradc
24-07-2008, 03:44 AM
hehe yep! pity we don't have a longitudinal engine, rear 6 speed dual clutch transaxle at ~480hp though!

Goku
24-07-2008, 04:13 AM
hehe yep! pity we don't have 480hp though!

You're working on fixing that problem though aren't you brad :D

valmes
24-07-2008, 06:32 AM
I agree...but I'm curious: what's your logic, dude?

It just feels right... ;)

bradc
24-07-2008, 06:46 AM
most of the way there :)

Turbo_Steve
24-07-2008, 11:42 AM
It just feels right...
Nuts: that was my logic too.


Sorry, yes, meant V6...think it was getting a bit late for me there!
I could have sworn the older ones were sequential, though?

Goku
24-07-2008, 11:15 PM
nope parallel, there are only 2 sequential ones I know of, FD RX7's and legacy's.

They are a pain in the ass to tune properly

Wodjno
24-07-2008, 11:19 PM
nope parallel, there are only 2 sequential ones I know of, FD RX7's and legacy's.

They are a pain in the ass to tune properly

And Supra's /pan

Goku
25-07-2008, 01:45 AM
Are they ?

I thought they were parallel too ?

bradc
25-07-2008, 02:37 AM
wasn't the 959 sequential as well?

Ryan
25-07-2008, 04:19 AM
wasn't the 959 sequential as well?

Yes it is.

Turbo_Steve
25-07-2008, 12:34 PM
Hmm, well the couple we did were definitely sequential as they had valves-a-plenty between the turbos. Admittedly now that I think back on it, this may have been an aftermarket setup in both cases...in fact the more I think about it the more likely that seems. Just seems a trifle odd that we had three cars off the boat in one go and they all had a very similar setup. Bizzarre. Maybe my memory is playing tricks on me......

pitslayer
25-07-2008, 01:00 PM
i prefer twin turbos. when someone asks you whats under the hood you could say
V6 turbo....and they wouldnt be that impressed...what you would actually say is
V6 Twin Turbo, sounds farbetter /lol

although reading through, noticed some of you have said, they hve twin turbos with twin intercoolers, why doesnt the VR4 run twin intercoolers? is it not needed because of the Ypipe?

Turbo_Steve
25-07-2008, 01:11 PM
Usually down to cost and space.
Primarily cost: a pair of intercoolers requires a lot of front bumper space and specialist design of ducting etc.

A single intercooler is a lot cheaper to setup, test etc, and simply slots into the front.

However, if they're a decent design, individual intercoolers are generally more efficient, as they have better individual airflow and are less prone to heat soaking.

The new 350Z kits are cunning, and run a pair of intercoolers commoned together at the outlet tank.

I think the new GTR uses individual intercoolers.

In fact, the more you look at the new GTR, the more like a 300ZX it starts to look, to be honest: the most significant mechanical difference being the drivetrain, which is basically backwards :D Very clever, though.....wish I'd thought of it.

The engine is essentially an evolution of the VQ unit in the 350Z (see the heritage there?) which was of course a massively updated version of the VG present in the Z32.

The GTR seems to be the best bits of many of Nissans best cars.....Engine from Z32, drivetrain based on R34, chassis based on 350Z (apparently) suspension setup copied from one of their luxo-barges and then the whole thing refined refined refined until it gleams.

Turbo_Steve
25-07-2008, 01:24 PM
In case you hadn't gathered from my last post, I'm a still a Nissan fan, and I really REALLY want a GTR :D I'd have had a Stagea if the legnum wasn't a better car all round....but so far much harder (Read more expensive) to tune...though that was part of the reason why it made such a good family car LOL

Wodjno
25-07-2008, 07:39 PM
Are they ?

I thought they were parallel too ?

Yes the Mk 4 was Twin Sequential.. The Mk3 was single Turbo ...

bradc
26-07-2008, 05:58 AM
Pits, depends on the layout and design of the car. The 3000GT is twin intercooler I think.

Kieran
27-07-2008, 05:53 PM
Yes the Mk 4 was Twin Sequential.. The Mk3 was single Turbo ...

In the UK yes, but the Jap Versions had a couple of Twin Turbo Models - The 2.0TT (1G-GTE) and the 2.5TT (1JZ-GTE). The 1JZ's turbos were parallel (unlike the 2JZ in the Mk 4). I think the 1G-GTE was also a Parallel twin but I'm not sure.

Wodjno
27-07-2008, 09:21 PM
In the UK yes, but the Jap Versions had a couple of Twin Turbo Models - The 2.0TT (1G-GTE) and the 2.5TT (1JZ-GTE). The 1JZ's turbos were parallel (unlike the 2JZ in the Mk 4). I think the 1G-GTE was also a Parallel twin but I'm not sure.

http://en.wikipedia.org/wiki/Toyota_Supra

Kieran
27-07-2008, 09:42 PM
http://en.wikipedia.org/wiki/Toyota_Supra

Interesting - Shame it doesn't mention if the 1G was a parallel or sequential turbo. It also doesn't mention that in the Jap Market the 1G was also available as a non-turbo?!:inquisiti

Goku
27-07-2008, 11:33 PM
Yea, I wouldn't put too much faith in some of the wikipedia information....

I'm pretty damn sure the only ones I have seen are parallel, though they are mostly the mk 3 ones.

pitslayer
28-07-2008, 01:19 AM
so out of interest would twin intercoolers work on a VR4, it wouldnt seem cost effective to me, as i guess you would have to make all new pipes for each turbo?
but would there be any major gains by doing this?

Turbo_Steve
28-07-2008, 08:50 PM
Assuming you could
a) find space for sufficiently large coolers (think thickness rather than width / height)
b) find sufficiently decent intercoolers
c) can duct air from the front of the car through to an area of negative pressure (e.g. vents on sides of bumper or in wheel arch)
then yes there will be a significant improvement over the stock item, as well as potential improvements over a regular front mount, as the pressure differential will be greater and the heatsoak will be less.

The biggest benefits, however will be to your radiator and aircon systems, which will breathe a lot freer.

The drawback is that this setup tends to weigh more, and as the intercoolers themselves are smaller they can sink less heat: as intercoolers tend to sink heat into themselves, and then cool into the airflow over time, this can be a limiting factor on performance.

However, a front mount suffers from reflected heat from components under the bonnet, as well as tending to get less overall airflow due to the restrictions behind it.

It's one of those horses for courses things, but look at it this way:
Most twin bank, twin (or more) turbo engines in expensive cars have parallel intercoolers on either side of the car.
This includes the Veyron, the EB110, the Z32, the new GTR and..ohh...some others (dunno about the GTO?).

It really depends on your overall setup.

Given the differences in pipe-length on the legnum, and that the output from the intercoolers would simply be commoned at the throttle body, the benefits are probably not worth the effort.

pitslayer
29-07-2008, 03:28 PM
cheers interesting read, i thought it would serve little purpose unless you could mount them so close to the inlet and get them really cool.

Turbo_Steve
29-07-2008, 10:06 PM
proximity to inlet really isn't that relevant. Airflow accross the intercoolers is the big big deal :)