Discussion
Log Mainfiold fitted to the MR2 Turbo. Cast Iron POS that is prone to cracking, can't handle heat and is basically inefficent due to unequal lengths but its cheap and can be manufactured in huge numbers easily.
The correct way. Equal length primaries, bolt to mount the turbo in place to the engine so it doesn't rattle off (See various threads on the superbly s
t HASS kits), good quality TIG welds and stainless steel rather than cast iron.
The correct way. Equal length primaries, bolt to mount the turbo in place to the engine so it doesn't rattle off (See various threads on the superbly s
t HASS kits), good quality TIG welds and stainless steel rather than cast iron.
Everything I've ever read on the subject of forced induction indicates that the prime function of the pipework between engine exhaust and turbo is to maintain velocity and heat. Velocity is obvious, heat is retained since loss of heat = loss of pressure, and pressure differential across the turbo will spin the vanes. At the outlet of the turbo, the function of the exhaust system is to dispose of the gasses as quickly as is possible.
There is no need for equal length pipework feeding a turbo, this is done on a NA car to scavenge. Each pulse of exhaust into the system will create a wave of pressure that flows through the system. At the collectors, the increase in pressure will flow both towards the silencer and backwards towards the other exhaust valves. It is relatively easy to see that there are peaks of pressure flowing around the system, and where there are peaks, there are also troughs. A NA exhaust is tuned to ensure that a trough arrives at an exhaust valve as that valve opens, thus presenting the minimum pressure on the exhaust side of the valve and making it as easy as possible for the engine to pump the exhaust gasses away. Obviously this will only happen precisely at one engine rpm, all others are compromises.
In a turbo system, things are different. The goal is to maintain pressure in the system between exhaust valves and turbo inlet. The engine must work hard to pump exhaust gasses into this space.
The reason that manufacturer NA manifolds are junked when tuning a car is because the manufcturers usually choose to tune their NA exhausts to boost power low down in the rev range, producing a wide power band but sacrificing power higher up in the rev range. Tuners are in contrast often happy to sacrifice a wide power band to achieve a higher peak power figure higher up the rev range.
I'm thoroughly unconvinced that spending £100's on replacing a 5 kilo manifold with some custom headers to save weight is a prudent way to spend cash when most tin top cars tip the scales at over 1000 kilos. It will help you go faster, but not for this reason.
I've read an awful lot on turbocharging. I thoroughly recommend A. Graham Bells forced induction performance tuning, it's by far the best book on the subject.
http://autospeed.co.nz/cms/title_Book-Review-Force...
There is no need for equal length pipework feeding a turbo, this is done on a NA car to scavenge. Each pulse of exhaust into the system will create a wave of pressure that flows through the system. At the collectors, the increase in pressure will flow both towards the silencer and backwards towards the other exhaust valves. It is relatively easy to see that there are peaks of pressure flowing around the system, and where there are peaks, there are also troughs. A NA exhaust is tuned to ensure that a trough arrives at an exhaust valve as that valve opens, thus presenting the minimum pressure on the exhaust side of the valve and making it as easy as possible for the engine to pump the exhaust gasses away. Obviously this will only happen precisely at one engine rpm, all others are compromises.
In a turbo system, things are different. The goal is to maintain pressure in the system between exhaust valves and turbo inlet. The engine must work hard to pump exhaust gasses into this space.
The reason that manufacturer NA manifolds are junked when tuning a car is because the manufcturers usually choose to tune their NA exhausts to boost power low down in the rev range, producing a wide power band but sacrificing power higher up in the rev range. Tuners are in contrast often happy to sacrifice a wide power band to achieve a higher peak power figure higher up the rev range.
I'm thoroughly unconvinced that spending £100's on replacing a 5 kilo manifold with some custom headers to save weight is a prudent way to spend cash when most tin top cars tip the scales at over 1000 kilos. It will help you go faster, but not for this reason.
I've read an awful lot on turbocharging. I thoroughly recommend A. Graham Bells forced induction performance tuning, it's by far the best book on the subject.
http://autospeed.co.nz/cms/title_Book-Review-Force...
That it was the other way round with the longer lengths being dictated by what cyclinder fires first or is this more a turbo thing? Pretty sure my manifold is equal lengths on the Elise and that's running a GT28.
[QUOTE]
I'm thoroughly unconvinced that spending £100's on replacing a 5 kilo manifold with some custom headers to save weight is a prudent way to spend cash when most tin top cars tip the scales at over 1000 kilos. It will help you go faster, but not for this reason.
[/QUOTE]
Pretty sure no one has said its a weight saving thing. Log manifolds are mainly put on as a cheap alternative to a decent, well designed manifold.
[QUOTE]
I'm thoroughly unconvinced that spending £100's on replacing a 5 kilo manifold with some custom headers to save weight is a prudent way to spend cash when most tin top cars tip the scales at over 1000 kilos. It will help you go faster, but not for this reason.
[/QUOTE]
Pretty sure no one has said its a weight saving thing. Log manifolds are mainly put on as a cheap alternative to a decent, well designed manifold.
Edited by Mr Darcy on Wednesday 30th June 15:52
Edited by Mr Darcy on Wednesday 30th June 15:53
doogz said:
mikeveal said:
I'm thoroughly unconvinced that spending £100's on replacing a 5 kilo manifold with some custom headers to save weight is a prudent way to spend cash when most tin top cars tip the scales at over 1000 kilos. It will help you go faster, but not for this reason.
Who said it was being done to save weight? Am i missing something here? I've never heard of anyone changing their exhaust manifold because they've found one that is lighter.mat205125 said:
The ugly cast POS that cars leave the factory with are there as they offer a cheap and easy solution to manufacture and install onto reletively modestly tuned road applications. They are restrictive, heavy, and inefficient for ultimate performance tuning, and are once of the first items to be junked when a tuned motor is built.
I still maintain that changing a manifold to save weight is just daft. 
mat205125 said:
Well quoted and poorly highlighted.
Weight is just one of the standard exhaust manifold's shortcomings, and saving weight in any part of the car is a benifit.
[seeIcanbeapedanttoo]Weight is just one of the standard exhaust manifold's shortcomings, and saving weight in any part of the car is a benifit.
Generally but not strictly true. Like anything it depends on your design goals. A heavy car is a requirement for towing a heavy load. A heavy car allows a greater ratio of sprung to unsprung weight, making it easier to produce a smooth ride. Sometimes it is desireable to add weight to improve balance...
Agreed that it is harder to make a heavy car corner, accelerate and brake.
[/seeIcanbeapedanttoo]
My original point was that there are two types of people who reduce weight of car parts without considering the cost/benefit ratio. Those with extremely deep pockets and fools.
I was quoting you to show that I misread your thread.
Edited by mikeveal on Wednesday 30th June 16:18
nicktruman said:
Hi everyone.
I have built a kitcar from scratch and am basing the body on a Zonda too. I built the car from scratch, starting with a Jag V12, made a chassis etc.. The challenge for me was not to make a zonda or a fezza, but to make something from nothing, or just junk.
My car is a twin turbo jag V12 zonda thing.. I have never understood why you would put a F360 bodyshell on a Peugeot, or Mr2, but i do understand why you would take a load of parts and make a replica (if that makes sense).
Now for sale on eBay. Starting price £10k. *cough*I have built a kitcar from scratch and am basing the body on a Zonda too. I built the car from scratch, starting with a Jag V12, made a chassis etc.. The challenge for me was not to make a zonda or a fezza, but to make something from nothing, or just junk.
My car is a twin turbo jag V12 zonda thing.. I have never understood why you would put a F360 bodyshell on a Peugeot, or Mr2, but i do understand why you would take a load of parts and make a replica (if that makes sense).
http://www.ebay.co.uk/itm/Twin-turbo-Audi-V8-Zonda...
Good luck with the sale, Mr Truman!
threadlock said:
Now for sale on eBay. Starting price £10k. *cough*
http://www.ebay.co.uk/itm/Twin-turbo-Audi-V8-Zonda...
Good luck with the sale, Mr Truman!
Ohhttp://www.ebay.co.uk/itm/Twin-turbo-Audi-V8-Zonda...
Good luck with the sale, Mr Truman!
dear
LORD!!!!
nicktruman said:
Hi Guys
Whats wrong with my car now? The V12 with the manifolds you didn't like have gone, and the car now has a nice Audi V8, the car drives and handles really really well, its also very quick and stops on a sixpence.
Regards
Nick
For me, it's the look of it that is wrong. To my eye it is hideous. As above though, looks like a fun project for you. Best of luck with the auction.Whats wrong with my car now? The V12 with the manifolds you didn't like have gone, and the car now has a nice Audi V8, the car drives and handles really really well, its also very quick and stops on a sixpence.
Regards
Nick
ETA: I've just had a look at the close-ups and I think it could use a bit of filler here and there
Edited by ManFromDelmonte on Tuesday 6th January 12:49
ManFromDelmonte said:
For me, it's the look of it that is wrong. To my eye it is truly hideous. As above though, looks like a great project. Best of luck with the auction.
In what way is it hideous? I take it you don't like mid engine things? The chassis is as per Ultima and that is not the prettiest car ever! It isn't that dissimilar from the real thing, ok different front screen (lotus Elise) but the dimensions are all the same as the early C12. I think the AMG V12 is quite a low profile engine so the Zonda has a slightly lower back. I had to user scissor doors because there isn't enough room in the garage for the Ferrari and this car. The front shape is dictated by the cooling system.
Originally the criticism of my car was my welding, that has passed the test of time even after driving through the rough terrain of a middle east dessert its still rock solid.
I guess I will never please everyone
But truly hideous it isn't.I don't know if you have seen this article, but it was by an independent motoring journalist.
http://www.motortorque.com/blog/2014-10/car-enthus...
http://www.motortorque.com/blog/2014-10/car-enthus...
nicktruman said:
I don't know if you have seen this article, but it was by an independent motoring journalist.
http://www.motortorque.com/blog/2014-10/car-enthus...
Nick,http://www.motortorque.com/blog/2014-10/car-enthus...
I certainly don't want to criticise the effort you've made because you've achieved a huge amount, but without the car being road-legal and fully registered I think your starting figure of £10k is unrealistic. I think you'll end up very disappointed because your expectations of its appeal to a casual punter are far in excess of its actual value.
You can guess all you like, but until you try and get it road-legal you've got no idea what problems a new owner will face in that process. It looks from your videos as though the engine burns oil, which must surely be a problem?
In profile, the roof line is higher than a Zonda's, and the cabin looks too short. The dashboard's leather lining looks as though it's not stuck down. The carpets are missing(?) and the body panels look as though they're a long way from smooth or even symmetrical. The whole thing looks like one man's scratch-built, cheap-as-possible project. It doesn't look like a car that someone else could be proud of, let alone with a price tag of £10k before the IVA process begins.
I really hope you are successful with the sale though, because the effort is impressive. Could you at least get an IVA report showing what needs to be done before it can become road-legal?
nicktruman said:
I don't know if you have seen this article, but it was by an independent motoring journalist.
http://www.motortorque.com/blog/2014-10/car-enthus...
One man's meat and all that... fair play to you though you've had a bash which is more than most of us would'vehttp://www.motortorque.com/blog/2014-10/car-enthus...
I agree with the starting price, but I honestly don't know where to start! I don't trust ebay as people leave to the last 30 seconds to bid. If it doesn't sell I'll just lower the price, as soon as you mention the word "offer" in the advert ebay block the auction.
There are no carpets - true, the roofline was made to fit me, it is the same height as the Zonda, however because the front screen is not as steeply raked it does make the cockpit appear a bit high. The panels are flat, but hand laid, not using moulds or bucks - and it certainly wasn't cheap.
It has been on the road, albeit in the Middle East, it was tested and passed for driving on the Bahrain F1 circuit (although I never did).
The one part of the car I don't like is the bonnet, it feels heavy and I don't like the shape, but the rest is nice, OK not Pagani perfect..
The engine was just cold and isn't burning oil, the turbos are brand new so they might be blowing a bit through the seals.
Its odd, on all the websites the car is on, and from all the 100s of people that have seen the car and seen it evolve, the only criticism comes from pistonheads. Even Pagani has given me the thumbs up!
There are no carpets - true, the roofline was made to fit me, it is the same height as the Zonda, however because the front screen is not as steeply raked it does make the cockpit appear a bit high. The panels are flat, but hand laid, not using moulds or bucks - and it certainly wasn't cheap.
It has been on the road, albeit in the Middle East, it was tested and passed for driving on the Bahrain F1 circuit (although I never did).
The one part of the car I don't like is the bonnet, it feels heavy and I don't like the shape, but the rest is nice, OK not Pagani perfect..
The engine was just cold and isn't burning oil, the turbos are brand new so they might be blowing a bit through the seals.
Its odd, on all the websites the car is on, and from all the 100s of people that have seen the car and seen it evolve, the only criticism comes from pistonheads. Even Pagani has given me the thumbs up!
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