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Post by thruxton on Apr 9, 2021 17:55:46 GMT
Rolling roads have a place and provide a service.
But you need an Industry Standard for in depth research and assement
that is not a RR.
Look at the pinical of race engines, do they use a RR for their data? .... er no, they don't.
Go and take a look at Nelson Race Engines from the USA whom I use to deal with.
Or Bill Mitchell Hard Core Racing from Long Island whom I also use to deal with.
As for TVR Rover based engines of which I have an encyclopaedic knowledge from the 3.5 to the Paris Dakar engines.
Look to Ray Webb formerly of Rovertec and then, after legal action from B M W V8 Developments, or JE Racing Engines.
It's all engine dynomometer work.
Only an engine dynamometer will give you that.
And the Heenan Froude will give you that.
Anything else is just not the way to do it.
If you research John Sleath you will soon find his credentials.
He is a very serious researcher and acclaimed engine builder.
He has held many records for different things in the world of engines and cars.
Also look at the people who use his services, that says it all!
Regards.
Rich.
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Post by dickie on Apr 9, 2021 20:11:33 GMT
The manifold is only the same price as a set of decent pistons  Manifolds will perform differently on differently tuned engines. This is part of an on going engine development for me. I can afford the Simpson Manifold so why not.
My old supercharged Mx5 had a Jackson Racing exhaust.
The only other candidate was Racing beat which is for a stock diameter system.
Thruxton is correct about dyno cell tuning for development work.
I happen to have a local race engine builder with both a dyno cell ( Water brake ) and a rolling road. He does my machining work for me. He has a flow bench and a few other toys.
A rolling road has its place for tuning a car for drivability
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Post by warpspeed on Apr 9, 2021 23:06:20 GMT
Another +1 for Rich.
Rolling roads are very convenient for some final tuning in the car, but for proper engine development you really do need a fully instrumented engine dyno.
There can be a lot of hidden power in an optimally designed exhaust system, but it absolutely must be matched to the engine as a whole, and especially the camshaft and power level.
Its no good using some race developed piece on your stock engine and fully muffled road exhaust, and expecting a miracle.
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Post by dadbif on Apr 10, 2021 7:04:49 GMT
Fastest and cheapest exhaust power increase? Ditch your catalyst, if you’re lucky enough to have an early car.
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Post by schercheeroo on Apr 10, 2021 9:32:47 GMT
I've never done any aftermarket stuff, but I've been through a few oem projects. The process is a bit like this:
The performance team creates an initial concept.
The concept is tested in a 1D simulation package.
The 1D simulation is used to refine concept.
The refined concept is then handed to design team.
The design team develop a 3D version of the concept in CAD, making sure it packages in the application.
The revised 3D design is retested in the 1D simulation package.
The 3D model will be handed to the simulation team, who then carry out CFD and FEA analysis.
Feed back from the 3D analysis will drive further revisions to the CAD model.
Meanwhile the design team will be in contact with manufactures.
Feed back from the manufacturer will drive futher revision of the 3D model.
The final 3D model will be retested in CFD and FEA, then handed back to the performance team to evaluate in the 1D simulation model.
Prototype parts are ordered and tested on the engine dyno. If the simulation guys have done a good job it'll work right and the engine calibration will be updated.
The manufacturer will produce soft tool parts which will again be tested on the engine dyno and the engine calibration will be updated.
The manufacturer will then produce hard tool parts, again tested on the engine dyno with calibration updates.
Final PPAP parts will be produced and validated on the engine dyno.
By the end of the project the part will have spent several thousand hours on the engine dyno consisting of performance testing, emissions testing and mechanical validation.
Also, the part will have several thousand hours of running in development vehicles and in the validation vehicle fleet.
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Post by dickie on Apr 10, 2021 10:55:07 GMT
Its getting very Exhausting reading all these comments.  |
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Post by Vindi (Russell) on May 4, 2021 12:22:54 GMT
Interesting ... my 2p worth
Simpson Exhausts have a really good reputation for their exhausts, I suspect this is a copy of one Simpson made for a friend of mine. He gained 12 bhp, but that was changing from a very poor manifold and full exhaust system made by Go Perform, and was on an extremely powerful NA car ... I'd still want some sort of back to back testing to confirm what this will actually give.
Many, many tests on MX5 manifolds have been done by very well respected companies, and also several independent tests have been carried out to confirm what gains are possible ... answer, very little ... often nothing at all. The standard manifolds are actually very good and the standard Mk2.5 one is genuinely hard to beat by much
The tests also confirmed that unless you have a turbo, a 2.5" pipe will lose you power, not gain it ... for a high powered NA build (200bhp plus at the wheels), 2.25" is optimal, for most builds 2" is ideal
I'd happily buy one of these because of the way it looks as much as because of what it will do. I have a £1000 exhaust sat in my shed that I bought because it's a few kg lighter than standard and being realistic, will gain me 2bhp. In the big scheme of things this is cheap for what it is
Russell
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Post by dickie on May 4, 2021 18:02:14 GMT
For those still interested in this thread.
My Eunos already has a straight through system with a metal mesh cat. I am currently using a Mk2.5 manifold with a Mongrel miss match of cheap parts, the only decent bit is the Sportex Back box ( not available for the normal Mk1 Eunos system ) the Sportex box is straight through and not very noisy 87 DB at Hillclimb noise test last weekend.
The Simpson Racing Manifold was developed for a Mx5 Road Rally Car for Mx5partsni so it is not a full on race manifold. When it arrives I will be fitting a new metal element cat and have a custom silenced mid pipe and back box made up. The only restriction will be the FIA approved cat.
I am planning to head above 8000 rpm once I have collected enough parts for a bottom end build.
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Post by Zed. on May 4, 2021 21:39:50 GMT
The Simpson Racing Manifold was developed for a Mx5 Road Rally Car for Mx5partsni so it is not a full on race manifold. the manifold in question is a nice looking item  mx5partsni.com/index.php/store/product_detail/218some googling will find ~10 years ago there was a similar looking manifold...  although these might have been a little expensive for most people at the time so were not a big seller..... there does seem to be a design style.... Rich. |
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Post by noobie on May 5, 2021 5:31:09 GMT
The tests also confirmed that unless you have a turbo, a 2.5" pipe will lose you power, not gain it ... for a high powered NA build (200bhp plus at the wheels), 2.25" is optimal, for most builds 2" is ideal I would not go by a single data point here. Nice video with comparisons (this guy is a treasure, has his own dyno and tests a ton of stuff. Highly recommend his other vids) |
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Post by Vindi (Russell) on May 5, 2021 8:44:15 GMT
The tests also confirmed that unless you have a turbo, a 2.5" pipe will lose you power, not gain it ... for a high powered NA build (200bhp plus at the wheels), 2.25" is optimal, for most builds 2" is ideal I would not go by a single data point here. Not really sure what you mean if I'm honest? Multiple tests by multiple companies and organisations testing literally hundreds of different setups and all coming to similar conclusions. Russell |
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Post by noobie on May 5, 2021 17:15:11 GMT
I would not go by a single data point here. Not really sure what you mean if I'm honest? Multiple tests by multiple companies and organisations testing literally hundreds of different setups and all coming to similar conclusions. Russell The vid is an example of an NA 4AGE picking up 5kw when going from 60mm to 3 inch exhaust. F20C's are at 180whp NA and pickup 5kw going to a 3 inch exhaust. Madjak saw a similar gain going from racing beat to full 3 inch exhaust on a (200+hp) BP. So what I'm suggesting is that this isn't quite as cut and shut as you say. It probably depends on the implementation. If you have any data to share, then that would be interesting. |
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Post by Vindi (Russell) on May 6, 2021 0:24:40 GMT
Engines behave very differently. Some engines need space, other engines need a certain amount of back pressure so if it's not to do with a BP it's of limited use. Adding a decent off the shelf 4-2-1 manifold to a 4age gains 15-20bhp, doing the same to a BP gains about 2bhp
I'll see if I can find the original threads, the most recent one was AK Automotive when they were testing for their exhausts, they settled on 2.25" as going to 2.5" lost them power.
I guess there's a lot of other variables to consider but I'd still be surprised if going to a 2.5" didn't lose power on the engine here and now. I know there's a lot more engine work planned so it might be needed later on. The car that I suspect this manifold was copied from was at 249bhp
Interesting reading up on Madjak's build, 13.8:1 compression and E85, wild cams, Honda intake, forged block and all sorts of custom work inside the head ... really an incredible spec, but he says it's about 200bhp. That's a much wilder spec than a couple of cars I know are running at 240-250bhp, although I guess it's a DIY build so isn't going to be perfect. I couldn't find anything about the specific gains from the exhaust, alhough he's clearly getting some good power and approaching it without following what everyone else is doing, which has to be a good thing
Russell
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Post by wannabe on May 6, 2021 9:09:03 GMT
Engines behave very differently. Some engines need space, other engines need a certain amount of back pressure so if it's not to do with a BP it's of limited use. Adding a decent off the shelf 4-2-1 manifold to a 4age gains 15-20bhp, doing the same to a BP gains about 2bhp I'll see if I can find the original threads, the most recent one was AK Automotive when they were testing for their exhausts, they settled on 2.25" as going to 2.5" lost them power. I guess there's a lot of other variables to consider but I'd still be surprised if going to a 2.5" didn't lose power on the engine here and now. I know there's a lot more engine work planned so it might be needed later on. The car that I suspect this manifold was copied from was at 249bhp Interesting reading up on Madjak's build, 13.8:1 compression and E85, wild cams, Honda intake, forged block and all sorts of custom work inside the head ... really an incredible spec, but he says it's about 200bhp. That's a much wilder spec than a couple of cars I know are running at 240-250bhp, although I guess it's a DIY build so isn't going to be perfect. I couldn't find anything about the specific gains from the exhaust, alhough he's clearly getting some good power and approaching it without following what everyone else is doing, which has to be a good thing Russell I'd be interested to see the AK Automotive stuff - I like their exhaust a lot! |
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Post by noobie on May 6, 2021 15:56:02 GMT
Engines behave very differently. Some engines need space, other engines need a certain amount of back pressure so if it's not to do with a BP it's of limited use. Adding a decent off the shelf 4-2-1 manifold to a 4age gains 15-20bhp, doing the same to a BP gains about 2bhp Interesting reading up on Madjak's build, 13.8:1 compression and E85, wild cams, Honda intake, forged block and all sorts of custom work inside the head ... really an incredible spec, but he says it's about 200bhp. That's a much wilder spec than a couple of cars I know are running at 240-250bhp, although I guess it's a DIY build so isn't going to be perfect. I couldn't find anything about the specific gains from the exhaust, alhough he's clearly getting some good power and approaching it without following what everyone else is doing, which has to be a good thing Sadly 4AGE's don't gain 15-20hp with just a header, 6-7 hp is more typical..if lucky. Much like a BP in that regard. No engine needs back-pressure. They need proper scavenge pulse timing. Once you have that, avg backpressure differences have marginal effects. By the way, Madjak's roughly 200hp was from his last dyno...220hp@the hubs. That compares favourably to 250hp@crank. A-B testing exhaust diameters is difficult because the exhaust is such an integrated system. Use a 3" midpipe on a 2.3" exit header and you get a large reflected pressure wave at the step change. That affects scavenge timing and hp, likely in a negative way unless it happens at the right place/time. Test like that and you'll tend to see optimum exhaust diameters close to header exit dia. I do agree that on nearly stock engines, playing with exhaust diameters does little more than increase drone. |
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le sigh