Twin or single turbo?

[hurtinit]

hey guys, got a few questions for you all.....

1. If going single turbo setup on the 1uzfe... wot exaclty needs to be done to the manifolds? do the size of the inlets have to differ at all?? What are the pros and cons to both single and twin turbo setup? pics would be great

2. currently my car (vl commodore) has got a thinker head gasket which has lowered teh compression, this was done when i purchased that car, is this a positive when turbo chargin the engine?

3. wot sorta horses power would i be looken @ with turbos??

Any info would be greatly appreciated!
thanks guys!
cheers justin

 

[Pro]

okay wait a second.
a VL ... does it have a 1UZFE in it or does it still have the RB30E in it?

thicker head gaskets are a sh1tty stop gap for lazy engine builders.

if they had gone to the trouble of removing the heads then you could have
1) bought a dremel for as much as the head gaskets cost you
2) removed that nice big chunk of aluminium casting that raises the CR - by removing it and making the combustion chamber a hemispherical shape, you improve swirl AND reduce your CR - both important factors when turbocharging and
3) have a new dremel to play with afterwards

my advice is to lose the thicker head gaskets and go to thin stainless gaskets (similar to the exhaust gaskets) and remove the extra head material.

http://www.lextreme.com/decompression.htm
^^^^^^^^^^^^^^^^^^^^^^^^^^
head here for my explanation of what to do.

 

[hurtinit]

mani

cheers for the info mate, because the engine already has the thick head gasket on it.. im gunna stick with it for the time being. Has anyone had any positive experience with this modification? any negative?

Btw single turbo on a 1uzfe... regarding the manifolds? do they have to be a certian diameterthe further they are away from the turbo? any info would be greatly appreciated and pics of manifold would be even better .... thkns for your time guys
cheers justin

 

[Lextreme II]

I have copper .093" in my 1uzfe engine right now and it was a pain to get it work properly. First with copper headgasket (HG) you would need to retorque the heads and its a day of work. You need to warm up the engine and take the parts out again to re-torque the heads while the engine still warm. Secondly due the the thicker head gaskets, the heads also move further away and you would need double up the lower intake gaskets to prevent leak.

Here is recommedation:
1. modify the heads chamber like above mentioned and use MLS gaskets
2. Get dished pistons and use MLS gaskets

Stay away from Thick Gaskets... it works but lots of work and its not the best method. I am saying this from personal experience with 1uz.

Single or Twin? Twin is double the work, double the trouble, double the fun and double the cost.....

 

[hurtinit]

hmmmm

cheers for that info, wot about manifolds? has anyonegot any pictures of there turbo manifods? would be great to see some different ideas? is there any pros and cons to a good manifold?? wot size piping etc, do you need tuned lenght?
cheers for all your info in advance!

 

[Pro]

in all seriousness, tuned length headers on a mild engine isn't worth the headache.

you have to work out flow rates thru different pipe diameters, gas speeds etc etc.

just make the manifold out of steam pipe to keep it cheap, and maybe size it down a shade under the exhaust port size to keep gas speed up.

oh, and have fun. it's just like a jigsaw puzzle

 

[hurtinit]

cheers for the info mate, im located in western australia, perth to be precise! if i chuck a 1uzfe and single turbo on her and then take over pits, wot are my chances of getting it passed with permitts for everything. I rang the licensing centre but they arent much help, all they tell me is "aslong as its safe, its ok"!

i dont wanna do all this work and find out there not gunna license it.
Any sugestions would be great, currently i have a vl commmodore with a carby 5 litre in her!
thanks guys!

 

[Pro]

well well well.

i'm in perth too.
considering the VL came with a 3.0L turbo, you should be able to register a 4.0L turbo easily as far as capacity regs go.

the only downside is you'll need an emissions test being a post 86 car - forced induction and V8s are a no go because they are considered to be 'excessive' in their emissions.

there are two ways around this.

fit a delco or put it on LPG.

 

[JBrady]

okay wait a second.
a VL ... does it have a 1UZFE in it or does it still have the RB30E in it?

thicker head gaskets are a sh1tty stop gap for lazy engine builders.

if they had gone to the trouble of removing the heads then you could have
1) bought a dremel for as much as the head gaskets cost you
2) removed that nice big chunk of aluminium casting that raises the CR - by removing it and making the combustion chamber a hemispherical shape, you improve swirl AND reduce your CR - both important factors when turbocharging and
3) have a new dremel to play with afterwards

my advice is to lose the thicker head gaskets and go to thin stainless gaskets (similar to the exhaust gaskets) and remove the extra head material.

http://www.lextreme.com/decompression.htm
^^^^^^^^^^^^^^^^^^^^^^^^^^
head here for my explanation of what to do.

Pro240c, I also agree that thick head gaskets are a poor way to lower compression... however... I would be cautious about grinding off the quench pads on the heads. The quench pads work to squeeze the mixture into a smaller area that is less prone to detonation. Large open combustion chambers make controlling detonation more difficult. In fact one very good thing to do when building an engine is to mill the surfaces to try to get the piston to quench pad distance as close as possible without touching.

The BEST way to lower compression is with custom dished pistons that match the quench pad dimensions and careful chamber work to move the mass of the compressed charge towards the exhaust valve. This creates better combustion and is less prone to detonation.

 

[Pro]

once again you are very right JBrady.

however, the new pistons route is a lot more expensive than milling away the quench pads (and thanks for the terminology too - i had no idea what their official nomenclature was!) - after all, if you were going to get rid of the copper head gaskets then the heads would be off anyway.

i personally think that using copper head gaskets is asking for trouble. gaskets are not designed to be right on the flamefront of combustion pressures - unless they're stainless steel. if you could get a titanium gasket then i would suggest you used that instead. by using a thicker gasket you effectively make the gasket exposed by moving the head further away from the block.

copper + heat = trouble. it's a very malleable metal that reacts poorly to heat.

 

[hurtinit]

im a vl turbo boy from way back.... now majority of vl turbos with huge horses are running copper head gaskets!

im as tight as they come... the car will only be used for weekend purposes... and a few runs down the strip, to me it sounds logical and a cheap way of doing it......

 

[ozvenom]

go the single

Hi i have turboed 2 1uz's 1 with twins and the other a big single . both are on stock compression engines (carefull tuning required.) the twins are t3 plain bearing off a vg30det. boost starts at 3500 rpm and is set at 11psi makes 400 rwhp and 1400lbs of rwtq. the single uses a 600 hp rajay plain bearing turbo mounted in front of the engine on equal lenth runners and 4 into 1 extractors 1 3/4" then steps up to 2 1/2" from collectors and merges together at the turbo .
it make boost from 3000rpm and revs too 7500rpm it has 2 boost settins 12 psi and 22 psi at 12 psi itmakes 430 rwhp and 1535lbsof torque. has yet to be dynoed on the hi boost setting as it requires avgas and a lot of time for tuning .
My point is that a well set up sinlge is by far more efficiant and cost effective if you have the room for it.

 

[Lextreme II]

Looks like you would make about 750-788 rwhp at 22 psi from the calculation. WOW!!!!!! My goal is 15 psi and aiming for 500 rwhp on a single turbo with .68 A/R.

 

[Pagong]

Look at that torque numbers...god damn!

 

[turboandrew]

Looks like you would make about 750-788 rwhp at 22 psi from the calculation. WOW!!!!!! My goal is 15 psi and aiming for 500 rwhp on a single turbo with .68 A/R.

Not exactly 430 rwhp = 12+14.7 psi = 26.7 psi absolute
= 16.1 rwhp per 1 psi absolute

22psi = 16.1 * (14.7 + 22) = 590 rwhp

It does not work this way: 22psi = 430 / 12 * 22

590 rwhp is still damn good for a stock 4.0 l with boost at 3000 rpm.

A motor that flowed a lot better and a more efficient turbo make make a lot more at 22 psi.

I bet a garret 67 wheel'd garret turbo would be killer on that motor

 

[LEXUSV8NZ]

once again... Where the hell is that drool bucket when you need it?
Very impressive OZVENOM, Do you experience much throttle lag from induction piping that long? Not that theres really any other way to do it to reduce the length of induction tract.
Mmmmm turbo 1uz in a cobra mmm.....

Logan

 

[ozvenom]

boost'n

Hi Logan no not realy it comes on boost at 3000 rpm and is instant responce between gear changes datalogging shows almost no drop in boost on changes but it helps having a 6 speed box. it's a great thing to drive the problem is you run out of road real quick .

Regards oz

 

[JBrady]

ozvenom, I think you may have converted Kw and Nm to horsepower and torque. The formula for Kw to HP is Kw x 1.34 = HP. So your 420hp would be 313kw... about right? However, the formula for Nm to TQ is to divide not multiply. The number to divide by is 1.36. I do not know what your torque numbers are but they could not be 1535lb/tq because even at your boost threshold of only 3000rpm... that would be 877hp. At 4000rpm that would be 1169hp... Your 420hp at a guesstimated 6500rpm would be 340tq. If you make it at 5200rpm it would be 420tq.

Very nice looking turbo system!

 

[LEXUSV8NZ]

it's a great thing to drive the problem is you run out of road real quick .

And the problem is...
Yeah I could see that happeneing in a hurry
What sort of weight is it?

Logan

 

[MatMan]

Holy crap Ozvenom !

Is that in a Shelby replica?
Just guessing from the stripes. . .