22 replies to this topic

[siztenboots]

this is the sort of kit I am looking at.

from a simple packaging view, cold intake , turbo outlet would all fit with standard chargecooler positions

http://www.full-race...roducts_id=2155

[FLD]

Yo! That looks like a packing nightmare! I'm currently looking at making a turbo manifold to fit T3 flanged turbo's. It'll be log type because of this packing issue and the T3 I have is a fair bit bigger than stock. My plan was for single exiting design keeping it all very tight to the motor. If your really interested in split turbine units would you be interested in me making mine a split flow log type manifold or would you really want the equal length headers of this sort of manifold? I'd be casting in SG75 nodular iron BTW.

[Duncan VXR]

Extra heat created by a tubi mani over cast is something to be concerned about in our setup and of course space is a serious issue. Don't discount a well designed cast Steve, more than upto the job and still question the point where a really big efficient turbo on our setup ruins it on the road or becomes a bit too much at full chat other than straight lines. Happy to give it a go though DG

[siztenboots]

I think there would be benefits on the T3 by having the 4-2 matched (c1+c4, c2+c3). Could the external twin wastegates be simplified to one ? reference: A twin scroll turbine housing uses dual side by side passages into the housing. When coupled with a pulse converter manifold that separates exhaust pulses as many crank degrees in the firing order as possible, a twin scroll or divided housing works to reduce lag, decrease exhaust manifold backpressure on the top end, reduce the potential for reversion, and increase fuel economy. The twin scroll is based off the same reasoning a tri-Y header uses: keep spent exhaust gases out of an adjacent cylinder drawing in fresh air. At high rpm on a turbo car, exhaust backpressure is usually significantly higher than atmospheric pressure, and often higher than intake manifold pressure as well. A divider between each of the two volutes allows the cylinders to expel the exhaust gases without it interfering with the fresh air for combustion. Since there are two openings, each a smaller overall volume than a single scroll design, the exhaust velocity of each pulse can be maintained. This also spins the impeller more easily because lag is a function of the scroll area. A single turbine housing opening isn't as efficient since cylinders on the exhaust stroke of the 4 stroke cycle contaminate the cylinders that are on overlap with exhaust gas. A conventional turbine housing is not as effective in using exhaust pulse energy to help spin the turbine up to speed as it does not exploit the energy contained in the pulses as well.

Edited by siztenboots, 26 February 2010 - 12:01 PM.

[Winstar]

I think there would be benefits on the T3 by having the 4-2 matched (c1+c4, c2+c3)

reference:
A twin scroll turbine housing uses dual side by side passages into the housing. When coupled with a pulse converter manifold that separates exhaust pulses as many crank degrees in the firing order as possible, a twin scroll or divided housing works to reduce lag, decrease exhaust manifold backpressure on the top end, reduce the potential for reversion, and increase fuel economy.

The twin scroll is based off the same reasoning a tri-Y header uses: keep spent exhaust gases out of an adjacent cylinder drawing in fresh air. At high rpm on a turbo car, exhaust backpressure is usually significantly higher than atmospheric pressure, and often higher than intake manifold pressure as well. A divider between each of the two volutes allows the cylinders to expel the exhaust gases without it interfering with the fresh air for combustion. Since there are two openings, each a smaller overall volume than a single scroll design, the exhaust velocity of each pulse can be maintained.

This also spins the impeller more easily because lag is a function of the scroll area. A single turbine housing opening isn't as efficient since cylinders on the exhaust stroke of the 4 stroke cycle contaminate the cylinders that are on overlap with exhaust gas. A conventional turbine housing is not as effective in using exhaust pulse energy to help spin the turbine up to speed as it does not exploit the energy contained in the pulses as well.

There are down sides to a twin entry turbine housing due to the extra surface area they are less efficient than as the equivalent single entry housing and thus produce less power overall which can be important if your aiming for high boost levels. They area also more prone to thermo mechanical fatige although they can't be worse than the std turbo lol

[siztenboots]

This is my current setup , gives a good idea of space

[cheeky_chops]

Yo! That looks like a packing nightmare! I'm currently looking at making a turbo manifold to fit T3 flanged turbo's. It'll be log type because of this packing issue and the T3 I have is a fair bit bigger than stock. My plan was for single exiting design keeping it all very tight to the motor. If your really interested in split turbine units would you be interested in me making mine a split flow log type manifold or would you really want the equal length headers of this sort of manifold? I'd be casting in SG75 nodular iron BTW.

How large(read laggy) are T3's in comparrison to OEM or garett GT28? Or is that a question that depends on exhaust/compressor spec (i know f all about this)

Could be interested in a decent log mani though Whats your price point?

[siztenboots]

There are down sides to a twin entry turbine housing due to the extra surface area they are less efficient than as the equivalent single entry housing and thus produce less power overall which can be important if your aiming for high boost levels. They area also more prone to thermo mechanical fatige although they can't be worse than the std turbo lol

How do you work out the "A" of A/R due to the additional turbine wall.

I know of the GM 2.0LNF , but don't the EVO's now also have this as OEM?

This picture is a single gate homebrew

[FLD]

Yo! That looks like a packing nightmare! I'm currently looking at making a turbo manifold to fit T3 flanged turbo's. It'll be log type because of this packing issue and the T3 I have is a fair bit bigger than stock. My plan was for single exiting design keeping it all very tight to the motor. If your really interested in split turbine units would you be interested in me making mine a split flow log type manifold or would you really want the equal length headers of this sort of manifold? I'd be casting in SG75 nodular iron BTW.

How large(read laggy) are T3's in comparrison to OEM or garett GT28? Or is that a question that depends on exhaust/compressor spec (i know f all about this)

Could be interested in a decent log mani though Whats your price point?

The T3 is slightly larger than the OE turbo in physical size but its going to come down to blade trim housing ratio's etc as to how laggy it'd be. Its used on the 1600 RST though so cant be too far off the right size. Lots of other turbo's use the T3 flange pattern though so you can mix it up a bit. What I could do is make a thick flange (ooer) to take studs but then have a small hole in the middle so it could be matched to any turbo. One I like is a VNT28 with a T3 compressor grafted on. Despite not being rated for petrol engine use doesn't mean it wont take it. It just means its not tested at that EGT level. I've not tried the holsett variant but I believe they are better.

I agree with some of the comments above, twin scroll housings only offer very slight performance benefits. I've tried it and now cant be bothered with the extra hassle!

The picture is handy, what I could do with is knowing just how much extra room there is down there to move out from the engine block. I'm keeping the turbo close in but any bigger than a T3 will be tight. Is there room behind the heat shield? An approximate ' I can fit finger, hand arm down there' measurement will do for now.

[FLD]

Yo! That looks like a packing nightmare! I'm currently looking at making a turbo manifold to fit T3 flanged turbo's. It'll be log type because of this packing issue and the T3 I have is a fair bit bigger than stock. My plan was for single exiting design keeping it all very tight to the motor. If your really interested in split turbine units would you be interested in me making mine a split flow log type manifold or would you really want the equal length headers of this sort of manifold? I'd be casting in SG75 nodular iron BTW.

How large(read laggy) are T3's in comparrison to OEM or garett GT28? Or is that a question that depends on exhaust/compressor spec (i know f all about this)

Could be interested in a decent log mani though Whats your price point?

Sorry missed the price point bit. I'm looking to be under 200 quid for a new casting. Then bank on 50-75 for machining. The price will depend on the price of SG iron at the time of casting but I certainly dont expect to be above 200.

[Duncan VXR]

Ran a VNT28 with T3 side on my old R5 turbo and worked really well - once you worked out how to control the boost spiking quite a few running them and have been for some time and no major issues to report. Went really well and only 1.4 Porkers now use VNT's on the turbo - not sure the difference in spec. In fact I think Saab may have used them also? Or was it just the diesel DG

[Winstar]

Porkers now use VNT's on the turbo - not sure the difference in spec. In fact I think Saab may have used them also? Or was it just the diesel

DG

no just the porkers using them, even then I've heard of durability problems the problem is that to meet the emissions for productions cars the EGT's are to high to make anything that moves durable not to mension trying to sheild the electrics that can't normally take more than 200'C

[Duncan VXR]

Porkers now use VNT's on the turbo - not sure the difference in spec. In fact I think Saab may have used them also? Or was it just the diesel

DG

no just the porkers using them, even then I've heard of durability problems the problem is that to meet the emissions for productions cars the EGT's are to high to make anything that moves durable not to mension trying to sheild the electrics that can't normally take more than 200'C

Ok, thought it may have been the diesel

Maybe not the turbo of choice for the vx and new turbo design has come on soooo much it should be easy to get a spec that gives you what you want.

The vains do sound kind of cool at idle

[Winstar]

Ok, thought it may have been the diesel

Maybe not the turbo of choice for the vx and new turbo design has come on soooo much it should be easy to get a spec that gives you what you want.

The vains do sound kind of cool at idle

they do use them in deisels due to the egt's being lower.

Shouldn't have have a problem using tham in a vx as you can map the egt's alot lower if you don't need to need euroIV emissions, just pass an MOT.

It depends how much boost you want over what flow range the problem with fixed geometry turbines is that if they are small enough to spin up fast then they can't produce the power for high boost and flow rates. Thats where the twin scroll can help but as said you still loose some power at high flow rates due to the extra wall friction.

[siztenboots]

looking at the holset range , and it seems to come down to a choice of making a hybrid , plus a bespoke manifold with a T3 housing to fit standard z20let ports or another engine (B204) , or making the twin scroll setup with all the headaches. The compressor side of a super HX40 does sound really tempting, and I think that this could be fed and spool at sensible rpm. HX40 super. Compressor inducer 60mm, turbine exducer 65mm, with #18 turbine housing. Compressor flow rated to 70lb/min.

[Winstar]

looking at the holset range , and it seems to come down to a choice of making a hybrid , plus a bespoke manifold with a T3 housing to fit standard z20let ports or another engine (B204) , or making the twin scroll setup with all the headaches.

The compressor side of a super HX40 does sound really tempting, and I think that this could be fed and spool at sensible rpm.

HX40 super. Compressor inducer 60mm, turbine exducer 65mm, with #18 turbine housing. Compressor flow rated to 70lb/min.

If you can get me the proper nomencleture of the turbo your looking at HX40 is just the frame size, I'll get you the proper maps

[siztenboots]

as you can see from the engine bay picture above between the firewall bulkhead and the block , not a lot of room so packaging may have to be a bit inventive. would an internal wastegate from work or since they are intended for diesel is the flapper valve going to be too small and make controlling low boost difficult? I have been trying to get dimensions for something like a 12cm2 housing and flange details based on what the saab guys use and how well that spools on a 2.0l If you had the bore and stroke ,plus the wheel details then can you generate a map with the rpms overlaid?

[Winstar]

If you had the bore and stroke ,plus the wheel details then can you generate a map with the rpms overlaid?

I've got a spread sheet that will estimate runing points and plot them on a comp map but you need to guess the VE and BSFC, unless you can calculate it for the enigne from logging.

From there you can match the turbine flow/power to work out the best match, you can only really do it with holset as they are the only company to dyno-map the turine stages.

could be that the flap valve would be small but depends on how much boost your after as diesels can run quite alot of by-pass.

Edit one of the best compressors that Holset do is also used on the Rotrex C38-81

Edited by Winstar, 01 October 2010 - 09:53 AM.

[VXT Tim]

I'd give a lot to know WTF you are talking about.

[Darcini]

I'd give a lot to know WTF you are talking about.

I think a Mod needs to move this thread to the Valhalla section