Building a 2.8L M20, need intake modification advice

[cdeason7]

I am in the process of building a 2.8L M20 and I am doing it right, researched what has been done and talked to folks like John at WOT (he did the head). I want to maximize the intake system to suit the 284/272 cam and increased displacement. I would love to add ITB's but until someone develops a CF airbox, I do not see the value. I owned a E30 M3 with MAXX Alpha-N and DTM replica CF airbox and it was amazing, best bang for the buck for the S14. I have found this mod (http://www.e30clubsa.co.za/forum/ind...m-to-maf-swap/) and have a stock S14 airbox that I may try to fit, much better design than the M20 stock airbox. Looking for modifications that have been tried and dyno proven, thanks for any suggestions.

[SkiFree]

talked to folks like John at WOT (he did the head).

I would love to add ITB's but until someone develops a CF airbox, I do not see the value.

Looking for modifications that have been tried and dyno proven, thanks for any suggestions.

Have you looked at John's dynos? Seems like you have an impressive dyno-proven improvement in the form of RHD ITB's and are potentially discarding them solely based on past experiences that do not correlate to your current project.

I humbly suggest you look at any number of the dyno threads involving the RHD ITB's.

EDIT: Also, welcome to R3v!

[whodwho]

They are available with a CF plenum, a couple installs running one:

318aye - http://www.r3vlimited.com/board/showthread.php?t=340688


kamotors - http://www.r3vlimited.com/board/showthread.php?t=225271

[cdeason7]

I actually have been corresponding with John about the RHD ITB's but I encourage you to take a look at the CF airbox's that are available in Germany for the BMW six cylinder motors, the design of the airbox can add considerable hp. I do realize that adding the RHD ITB's will be a worthwhile modification but with a BMW Motortsport replica, I think the gains will be considerably more. I have a engineer friend in Germany with a 2.7L S14 that produces 400hp, he always talks about the system.

[whodwho]

FYI, You can run a S54 plenum you just have to go boosterless. It also might depend on the plenum you are trying to run, I am running an AA SC one (which is fairly small overall)

[SkiFree]

I understand that an airbox that is heavily designed/engineered like the bmw motorsport parts has the potential to add additional power. However, bear in mind that those boxes represent countless hours of R&D and large motorsport budgets. Augmenting a system designed for the S54 (or otherwise) for an M20 would obviously not yield the same results.

To think that any company/team would allocate the needed resources to go back and develop such a system specifically for the antiquated M20 is optimistic in the extreme. Let alone, find enough people to cough up AT LEAST several thousands of dollars each to break even on the project.

To base your decision to NOT run a proven significant power adder like the RHD ITB’s because you are after something that does not exist seems a bit illogical.

[digger]

I want to maximize the intake system to suit the 284/272 cam and increased displacement. I would love to add ITB's but until someone develops a CF airbox, I do not see the value..........Looking for modifications that have been tried and dyno proven, thanks for any suggestions.

many things dont seem to make sense about this .... RHD makes ITB with CF airbox but you dont want to use it despite it showing proven gains, somehow that is not worth it. Yet somehow the s14 box can be made to fit and have the correct requirements for the m20 despite the geometry being for an engine with basically nothing in common? its irrelavant that a s14 can make 400bhp as there are probably about $10-15k of other mods into the engine besides a "german" airbox

i think you have unrealistic expectation for what an airbox can and cant do. if you look on the s54 the $5000 CSL airboxes, they dont make that much gain over the Evolve eventuri when you take out the effect of the ECU tune its alot about the sound and bling

the only way to come up with something fundamentally different is a booster delete and a custom designed one, then you need to decide if ITB or single TB and that dictates the airbox

[cdeason7]

I do realize that I am being illogical because I want something that does not exist. I have attached a picture of the airbox that I used on my M3. The reason that I refer to a German airbox is because I have seen firsthand the quality of the pieces. What I am planning to do is proceed in a 3 step process, dyno the stock airbox/afm, do the MAF modification based on the South African website, dyno this and then evaluate the cost/benefit of the RHD ITB's. I spent about $1800 on MAXX Alpha-N and the DTM airbox, gained over 20 hp, the throttle response and sound were incredible. If you had experienced this on one of your cars, you would understand why I would want to duplicate this.

[digger]

the RHD setup gives way more than 20hp over bone stock probably closer to 35hp and that's on bone stock b25, the b28 probably utilises it even more. Compared to a what you're planning with maf conversion on a 3L you can expect 25-30whp more just due to the RHD manifold setup I.e fully tune compared to RHD plus full tune so the gain is the manifold not better fuel and timing as that's what happened on mine

[cdeason7]

So the complete RHD kit including airbox plus MAXX Alpha-N will run about $2000 USD. I can get that down to about $1500 by selling the parts that I have. Gaining an additional 30hp for $1500 is a no brainer.

[digger]

Dont run maxx alpha n. I'd get ms pnp