M20B25 headers manifold BTB or ?

[ambre]

I am renovating a street BMW E30 325i 1986 with Mtech 1 kit. Never been modified. Car is located in France (LHD). No cat.

For the engine, below are the planned mods:
- Ross racing custom forged pistons (stock origin specs) => it was difficult to find Mahle stock ones new
- H-beams rods 135mm (M20B25 origin length) from M52B28 (lighter than M20 stock ones)
- I am considering replacing the stock cameshaft by a Schrick 272 and adding a custom tuned chip (Delage in France or SSSquid)

While renovating the engine the idea is to take this opportunity to slightly improve it (street, no track).

I have researched to replace the headers but I'm having a hard time to figure this out. I am not convinced by the Ireland Engineering ones. They are made in the US but they use 409 stainless steel quality for their street and track version (304 on the racing one but not a good fit for my build). My objective is to first purchase nice piece and to improve over the stock version in terms of efficiency. But again my engine will be stock or slightly improved. I prefer to mention I want to be cautious to not purchase headers which could decrease the performance. I've seen posts from E30 "veterans" mentioning performance headers would not be a good fit a stock M20.

BTB is highly praised, high performance headers with high quality built. Problem they are insanely expensive (quote was 1800+ euros). So the question is beside BTB, what other alternatives are recommended today ? well designed and built to last, improving performance over the stock headers for the spec above, and less expensive than BTB

Thanks!

[tha881]

One thing is certain, there is more choice when looking for a manifold for a left hand drive car. Have you checked schmiedmann? I dont think you need to spend the money on a BTB as I'm sure they are designed for RHD cars anyway. Supersprint look very well made but are expensive. This french parts website have a budget one, maybe contact them and see if it provides any power gains?

https://cyl6.com/

[JungleGus]

The cost in BTB is the R&D and quality for proven power...unless you can get your hands on something like the old Hartge/Alpina/RD manifolds (which I believe BTB has taken notes from), from what I've been able to tell, pretty much everything else doesn't really gain much power.

The IE long tube header looks interesting but I hear mixed things about IE customer service (although fairly cheap outside of import costs).

Schiedman look interesting and pretty cost effective. EU based too

LHD make things easier without the steering linkage to clear - but I don't know a lot about options there.

Personally - I'd probably just hold out for a BTB or just stick with the stock manifold. We're talking marginal 5-10 hp gains (maybe 12-18 if you're optimistic on BTB) vs. the 30-40 for your stroker and cam. It's always something you can change later.

[minesapint]

Read this from the Wiki
https://www.e30zone.net/e30wiki/index.p ... t_Manifold

[ambre]

thanks for your inputs.

BTB fits also well LHD according to them despite the fact they are designed for RHD to clear the steering rack.

Supersprint is almost as expensive as BTB but difficult to find info on gains. I will pass.

IE I have mixed feeling about the quality. Schiedmann seems to be a good affordable option, not sure about the build quality. I will reach out to them to learn more.

Minesapints thanks for the link. I've read it many times, this is how I learned about BTB. But I thought I would ask as the market is constantly evolving.

[reggid]

I am renovating a street BMW E30 325i 1986 with Mtech 1 kit. Never been modified. Car is located in France (LHD). No cat.

For the engine, below are the planned mods:
- Ross racing custom forged pistons (stock origin specs) => it was difficult to find Mahle stock ones new
- H-beams rods 135mm (M20B25 origin length) from M52B28 (lighter than M20 stock ones)
- I am considering replacing the stock cameshaft by a Schrick 272 and adding a custom tuned chip (Delage in France or SSSquid)

While renovating the engine the idea is to take this opportunity to slightly improve it (street, no track).

I have researched to replace the headers but I'm having a hard time to figure this out. I am not convinced by the Ireland Engineering ones. They are made in the US but they use 409 stainless steel quality for their street and track version (304 on the racing one but not a good fit for my build). My objective is to first purchase nice piece and to improve over the stock version in terms of efficiency. But again my engine will be stock or slightly improved. I prefer to mention I want to be cautious to not purchase headers which could decrease the performance. I've seen posts from E30 "veterans" mentioning performance headers would not be a good fit a stock M20.

BTB is highly praised, high performance headers with high quality built. Problem they are insanely expensive (quote was 1800+ euros). So the question is beside BTB, what other alternatives are recommended today ? well designed and built to last, improving performance over the stock headers for the spec above, and less expensive than BTB

Thanks!

if i was you id look for a different supplier for forged pistons. you want 4032 alloy and OE replica. topend in the USA can do it easily with JE branded
M52b28 rods are I-beam
there are slim pickings for headers, im about to get a custom set made. there a knockoff RD headers (still way too much $$$ for ehat they are) but dont know if they fit RHD (they are made by "RD" but not the same quality as the originals) then thre is the IE ones which are knockoffs to with poor quality
As for supersprint look at the work of art S54 headers and the generic stuff they pump out for big $$$ for the m20
id just leeping an eye out for used sets on various ebays around the traps