I’m getting my Eunos sorted for the summer and I’m looking to get a new exhaust manifold and potentially a new downpipe as I think my current one has a hole or leak somewhere. I get a hard blowing sound under heavy acceleration and also a weird popping noise from under the heatshield when the car is warm and idling.
So far I’m looking at getting either an I.L Motorsport 4-1 manifold from Mx5 Parts, or a Jackson Racing 4-2-1 from Moss. A left wing choice I guess would be a Japspeed system but from what I can gather, they are just ebay tat. I’ve heard bad things about the Mx5 parts own brand manifold cracking etc, and I can’t justify the cost of a Racing Beat manifold so those two fit the bill. I’ve also seen Mx5 city have a manifold but judging by their rep I might give it a wide berth!
Does anyone have any experience of the I.L Motorsport manifolds? They look decent, there’s less faff with o2 sensors as well I guess. Does 4-2-1 make such a difference?
Also, is buying a downpipe worthwhile? SHould I be fussed about it? from what I can gather they are pretty sturdy as standard so if any bit of the upper system is knackered it probably won’t be the downpipe and for £150 from mx5 parts, I could probably spend that money elsewhere on the car.
If anyone can offer some advice that’d be really helpful as I’d like to order the parts asap to fit next weekend :)
Only manifolds made for the Japanese market will fit with a 370mm cat. So the JR manifold won’t fit unless you have a 440mm cat.
I brought a MX5parts 4-2-1 manifold for my 96 Roadster back in 2005. Back then, MX5parts got their German manifold supplier to knock up an adapter to bridge the gap between the down pipe and cat.
I had a hairline crack after a couple of years, but that was probably caused by the ill fitting German adapter. My cat died, so I just replaced it and the adaptor with a new 440 cat Since then, flawless. Its 11 years old.
Buy a new 4-2-1 manifold and cat. Given the effort needed to change the manifolds, you’ll be glad you did, that you don’t have to worry about shearing cat studs or down pipe bolts. The cat will add £80 or so to the bill, if your car is old enough, you can fit a cheaper cat pipe instead.
In theory, 4-2-1 is better for the lower range, 4-1 is all top end, though I suspect the ILM product is just a straight copy of standard.
Been pondering fitting a 4-2-1 to Mitzi, but it would end up being a full system, as well. Expensive…
The Mx5Parts manifold has had some good customer reviews. Their pattern cats seem good value, but apparently there are three lengths. Needless to say, Mitzi is on the cusp between 440mm and 475mm!
I have a cobalt 4 to 1 and a cobalt decat and full exhaust on my 91 eunos auto sounds incredible and has given a descent boost in power the manifold is off a manual with a little bit of heating and bending I made it fit the auto also I bought all of it off ebay for a total of £66 so before you buy try keeping your eye on ebay for a few weeks to see if any bargin come up
This just gets more confusing!haha! Thanks for all the input so far, especially saz. Glad to hear your mx5 parts manifold is still going strong. I’m wondering if I ought to just buy that manifold and downpipe and maybe decat the car with one of the silenced decats from mx5 parts. If my car is a 94 import would it need the cat for MOT? I’ve heard differing views on this; some say yes, others say no!
If no then I guess I’ll just go for the IL motorsport manifold and keep the downpipe and cat in place. Wish I could find a Cobalt manifold though as my backbox and mid pipe are Cobalt, and it’s fantastically well made. Why did they stop making them!
I run a 93 import 1600 with 4-2-1 from a guy in sheffield with decat pipe and a s/h believed to be Cobalt big bore stainless system [ s/h from another guy in Sheffield] total cost £ 225 ish nice tone etc on that age you may not need a cat ,mine mots ok
The 4-2-1 manifold runs to the cat; you don’t need to buy a downpipe. Personally, I’d spend the extra £20 on a 440mm cat, not the decat. Decats don’t really add anything to performance, they make your car smelly, they can sound horrible, and you are going to spend time arguing with your MOT inspector.
I’m guessing Cobalt’s Chinese supplier moved on. The Cobalt systems, like most Chinese manifolds, were straight rip-offs of RB systems. Plus Moss charged too much for them. They’re just the same as the £120 1.6 manifold for sale on Amazon.
Imports up to early 94 can get away without a cat uk cars from august 92 must have a cat make sure up put the front sensor on your new exhaust or your car will struggle to bring down its co2 level to within permitted levels as mine did
Does anyone with an Mx5 parts manifold know if they supply all the gaskets to go with it? I think I’ll order one and then it’s up to whether or not I fit a new cat or just go the decat route. Are there any pro’s to even out the obvious cons? Aside from the manifold I guess I just need some sealant for the gaskets, anything else I should change while I’m down there?
They only supply the manifold-to-head gasket, but I’d reuse the existing all metal gasket; its much better. You will need a down-pipe to cat gasket. If the surfaces are clean, you won’t need any sealant.Optionally, some thread-lock; you may find some of the headstuds will unwind themselves with the nut attached. Some might just treat this as if its a bolt, and just refit, but its worth separating the nut from the stud on the bench, and refitting the stud properly, with some threadlock on it.
I’m bad I checked out where I bought my manifold from and I’m still unsure as to the manufacturer as it was a customer return that was sold on again as non returnable new item as I knew I would have to modify it to fit mine I didn’t care 20 min of heating and bending and it fits my auto perfectly here’s a pic maybe some one recognises it
Just wanted to say thanks for all the advice I received on this thread, after all the deliberation I picked up a manifold from mx5 Parts with a silenced decat and spent the weekend getting it all fitted. All in all a simple, if rather strenuous job, fighting with rusted bolts is not fun, but got there in the end! Had to buy a new o2 sensor in the end as mine was welded to the manifold, nothing could remove it! Now it’s on to the next job of sorting out the suspension, HSD Dualtechs will be along soon all being well
