Turbocharger project
Discussion
love machine said:
As soon as you're mucking about with increased charge density, it throws the standard chamber characteristics out of the window. I reckon forged pistons are a waste of money unless you're building a BDA style engine. (Ever melted a cast piston?).
Yes on several occasions in test engines and switching to a forged piston isn't just about increasing strength to survice when a knock condition is present.
In certain applications forged pistons are extremely neccesary in order to maintain reliability in a high reving engine, an engine with high combustion chamber pressures/temperatures etc.
Matt
love machine said:
(Ever melted a cast piston?).
Very easy to do with forced induction, especially if the engine is not fitted with knock sensing circuitry. That, and my forged Cossie pistons were 35g each lighter than the cast jobbies (which were patently NOT suitable for turbocharged applications despite the supplier's -a German Saab 'tuner'- claims they were) they replaced.
OK, I have another question about "blowing" an engine. I am about to start work on my 2.7l v6, the Honda unit from an old police rover 800, install and feel that the only way to get a bit more out is to blow the air in! Now I am only looking for, relatively, low boost as I don’t want to have to change to many of the internals. I was originally thinking of using a supercharger, but, the engine would be the wrong way round, the belts at the back and the air intake at the other end, which would mean a very long input shaft and all of the complications that would bring, also the height would be a bit of an issue as well. So I am turning to a turbo, or perhaps two! The engine will be attached to a VW Beetle transaxle and is therefore running longitudinally in the chassis and I was thinking that twin exhausts would look quite cool out the back probably from a back box from a MR2 or similar, it also removes a lot of plumbing and worries about equal lengths of pipe! The original manifolds give me two short 3 into 1 headers to which I could attach small turbos, one either side, collecting air directly from the outside, using the ducts on the top of the rear quarter panel. These could then blow through two small intercoolers, one each side, in the front of the wheel arches before coming together to feed into a new plenum, I would have to make. I know that there is enough room in the wheel arches, some people who have fitted water cooled lumps use the space to fit two mini radiators for the engines with no problems, and the side to side clearance around the engine is huge. That is the plan, my questions are where do I source two small turbos from and am I best off feeding air into the plenum through two throttle bodies or joining the air inlet prior to and just fitting one? I was thinking that the turbos would come off a small “city” type car, possibly a diesel (?), with an engine of about 1.3 / 1.4 as that is half the v6! I have read a couple of the books on cylinder head work and come to the conclusion that as I only want a small amount of boost leaving everything, reasonably, standard would be best. I will be stripping the head down and attempting to make sure that the flow is as smooth as possible but will not be attempting major head reworking. Does anyone have any great ideas? Am I barking up completely the wrong tree? Have I missed anything blindingly obvious?
Many thanks,
JonL
Many thanks,
JonL
JonLeeper said:
the engine would be the wrong way round, the belts at the back and the air intake at the other end, which would mean a very long input shaft and all of the complications that would bring
If you use an Eaton or similar, the drive and air intake are at opposite ends of the blower so from that point of view it could work out quite handily. In fact people have even been known to fit them 'back to front' in a conventional longitudinal installation using a jackshaft to drive them from the rear, because it simplifies the air routing enormously.
you could always go for a single turbo! this would simplify thing no end. you would only need 1 waestgate, 1 intercooler and the pipe work would be much easier! also would make sorcing a good turbo easier as you only have to find 1 in good working order, not 2!!!
as for the pipe work, juts join the two headers together in a Y pipe and bolt the turbo on the end! i would fab a braket to support the turbo though as you dont want to stress the manifolds or joining pipes too much!
what is the compresion ratio of the Honda V6? 10.0 to 1?? if it is i would recon you could get away wit habout 5-6psi with an intercooler.
Chris.
as for the pipe work, juts join the two headers together in a Y pipe and bolt the turbo on the end! i would fab a braket to support the turbo though as you dont want to stress the manifolds or joining pipes too much!
what is the compresion ratio of the Honda V6? 10.0 to 1?? if it is i would recon you could get away wit habout 5-6psi with an intercooler.
Chris.
2.7l Honda V6 - unless you know it has some problems dont bother striping it they are very reliable and some of the parts are a bit on the pricey side ( head gaskets £ 80 a pair, bottom end shells £ 300 a set ).
Good 2nd hand engines are easy to come by now for £ 100.
The engine makes aprox 175 bhp as standard so with 5-6 psi boost your up to about 230 bhp with a relativly simple turbo set up ( slightly less for s/charger ).
At that sort of boost and considering the number of good cheap second hand engines about I would just leave everything stock, the block casting is the same as for the NSX engine although the crank, rods, pistons, liners and the heads were all changed on the NSX but the inlet manifold including the variable inlet runer gubbins was the same. You can then use the original injectors, ECU and all the standard control modules for the variable inlet vanes etc. and just use a rising rate regulator for the increased fueling. A decent intercooler would be at the top of the must have list though as the fairly high compression ratio even with 5-6 psi boost is well within the detonation range in the summer, plus intercooling is so cost efective you shouln't even be thinking of FI without it.
Good 2nd hand engines are easy to come by now for £ 100.
The engine makes aprox 175 bhp as standard so with 5-6 psi boost your up to about 230 bhp with a relativly simple turbo set up ( slightly less for s/charger ).
At that sort of boost and considering the number of good cheap second hand engines about I would just leave everything stock, the block casting is the same as for the NSX engine although the crank, rods, pistons, liners and the heads were all changed on the NSX but the inlet manifold including the variable inlet runer gubbins was the same. You can then use the original injectors, ECU and all the standard control modules for the variable inlet vanes etc. and just use a rising rate regulator for the increased fueling. A decent intercooler would be at the top of the must have list though as the fairly high compression ratio even with 5-6 psi boost is well within the detonation range in the summer, plus intercooling is so cost efective you shouln't even be thinking of FI without it.
OK, so what you are saying is that I should buy a riding rate regulator, sort out the loom from the rover and just use it as stock? Will I sitt be able to lose the Cat? I will not be able to map the ECU at all and will it cope with all of the extra? The loom is really a very complicated thing, I do have the Rover electrical manual for the 827 but as I say it is very complicated and I was hoping to simplify the system somewhat by using an aftermarket ECU, such as the emerald or magasquirt. Is this not a good idea? It seems that every time I ask a question I find the answer means that I need to ask several more!
Thanks for the responces though and keep them comming as they are all very useful.
Jon
Thanks for the responces though and keep them comming as they are all very useful.
Jon
Using just the rising rate regulator keeps everything stock and is the cheapest and easyest option but is limited to 5 - 6psi max.
The Honda v6 will take 5 - 6 psi intercooled stock without any problems.
If you use megasquirt or some other ecu you have more options over boost and rpm limit but you introduce other complications.
A couple of these would be how to control the variable inlet vanes ( I would just get rid of them and not worry about the low rpm torque gains ) and how do you trigger the ecu - this engine had a strange arangement where it was trigered from the back of the cam wheel on No1 cylinder bank.
If you havn't already got it a good turbo book with some actual examples is Corky Bells Maximum Boost
The Honda v6 will take 5 - 6 psi intercooled stock without any problems.
If you use megasquirt or some other ecu you have more options over boost and rpm limit but you introduce other complications.
A couple of these would be how to control the variable inlet vanes ( I would just get rid of them and not worry about the low rpm torque gains ) and how do you trigger the ecu - this engine had a strange arangement where it was trigered from the back of the cam wheel on No1 cylinder bank.
If you havn't already got it a good turbo book with some actual examples is Corky Bells Maximum Boost
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