348 Intake project discussion

Lots of issues doing that for sure. Thinking large airbox, probably new intake runners since that's the easy part, 70mm TB, all going to stock air box, some new semi rigid hoses. Literally drop in, no wiring or plumbing or fabrication changes. If you can get the chips flashed that would be good.

Waiting for TB I bought and I have MAF's so I will measure but I am pretty sure the MAF ID is largesr than that TB ID at least to my eye ball. So a TB with throat the size of the MAF ID or slightly larger is a good starting place.

Actually I know the 348 TB size, let me go measure the MAF

 

Yep the MAF has 13mm larger ID than the TB. I recall from old TB porting threads that alone got 22% more air.

Then in you look into the intake (thanks Ernie) you can see the air smacks into the intake runners, no trumpets or anything like the 355 has, it seems if the TB flange had a bigger ID as well as a bugger TB it would be not insignificant.
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The issue is if you go too big you need EM, the trick is just big enough to increase flow, efficiency, response and some power without having to stick new EM/ECU in. I mean if your putting new EM in like the Maxwell intake needs that they don't bother telling you, like Kevzep wans to do then hell ya.. dual 102mm TB's!

 

Makes sense, thinking larger plenum with larger or ported TB which is probably all that is needed since larger than the maf's is not doing much anyhow. More air and more efficient into the engine is about all that is needed. That and the chips I still need from you .

Covid got in the way so never made it out there, kid got out of Marines already so is no longer in Pendelton.

 

With new workshop coming and engine rebuild done I need a new project. Even if I never install an intake just designing and making it would be fun, my brain must have a problem at all times and problems I know I can solve are no fun. Not sure I can solve this which makes it irresistible.

Were talking small hobby grade workshop here, bench top equipment but I have skills.

 

Doubt you can get more than 10 hp from stock tune. I have seen dynos showing 50-100 hp over stock same dyno at wheels though. Think they had chips tuned, exhaust, TB porting, adjustable FPR etc but it was the Motonic 2.7 ecu none the less not aftermarket ECU's. I'd be happy with 350 at the crank. So were talking +30 over Spider that's not trivial to do despite Capristo and other exhaust mfg's boasting to the contrary. Bolt it on and get 25. Ya right. More like 10 downhill with the wind and no cats.

AndyW's Spider was one such car. It was this one.

 

Yep Tim is alive he's posting with you right now. He is the guy.

AndyW had his done in Maryland forget the shop name but its a big well known one.

 

Open plenum meaning no top half and the intake runners exposed? The tb"s bolt to the top half of plenum so having trouble visualizing what an open plenum is.

 

Pretty sure the 355 itb conversion plugzit did had the same issue, not enough fuel up top. Definitely have to deal with that aspect.

 

Putting 355 ITB on the 348 is discussed. It has been done.

This is a 348 intake thread not a 355 intake thread. Modifying 348 inake is the topic, the thread has nothing to do with a 355.

 

No worries!

 

btw, I am not thinking 400hp with new EM and new injectors, thinking more along lines of 330 range with minor mechanical changes, actually working on new TB's right now actually. Pretty sure injectors will support up to 350 hp at the top end at 90%. Won't happen without some Motronic changes however, anyhow... it's fun designing stuff will prototype in CF alloy, trick is not to go to far or you open new rabbit holes. Previous 355 ITB project was shooting for the moon. Won't be doing itb's.

If I do anything at all, right now its just design and prototyping part time but the thread provides information and insights along the way. If I do it I will dyno before and after.