65mm throttle body and MAF

[lars49]

Thanks guys.

[torq455]

why not keep the MAF? it's a more accurate system. MAP calculates air flow, MAF measures it.

[IsaacHayes]

3500 plenum is 65mm, so you are good there. I have a 65mm TB (LX5) and the bore is perfect match with the 3500 plenum. It's a good combo. Use 3" air coupler and pipe and you'll be good there. And yeah you could go OBD1 and go speed density, or if you have a tuner for the OBDII 3400 ECM already you could edit out the MAF and work off the MAP tables I guess.

The MAF connects with 3" pipe, how small is the inside of it then?

[MidnightriderZ24]

if youre swapping why not go with a speed density system and get rid of the maf?

[lars49]

All the good stuff, port the LIM, port the exhaust, match ports between 3500 UIM & 3400 LIM, 65 mm thottle body ported to 3500UIM.

So for best intake flow it seems the pipe from the trottle body to the MAF, the MAF and the pipe from the MAF to the air filter should be 65 mm to minimize the flow impedance.

The problem is finding dimensions on usable alternatives. Would an LS1 sensor be the right size for example, and would it work with 3400 engine computer?

[payback]

what kind of tuner do you recommend MY91? im also doing the same swap only im planning on using ported 3400 U&LIM's. i suppose i should also get the 65mmTB it just makes sense...sheesh this swap is getting expensive lol.

[lars49]

This is going into an MGB. I am mating a 3500 plenum to the engine. Better flow at high end.

[MY91GT(Z)]

you should get a tuner to get the most out of it other then that u should be fine. and what kind of vehicle do u have?

[payback]

I purchased the 65mm thottle body from WOT for my 3400 project. Since the diameter of the thottle body is larger than the original it seems to me that I should be using a 65mm inlet to it to maximize air flow. That would require I also use a 65mm MAF. Is there any such MAF available? What issues if any will I have with the computer.

i highly doubt you need a new MAF. as for the TB idk lol. you could possibly port match the intake to the throttle body but i don know what kind of gains ud get from that. WOT recommends the 65mmTB for the ported 3500 manifolds.

[lars49]

I purchased the 65mm thottle body from WOT for my 3400 project. Since the diameter of the thottle body is larger than the original it seems to me that I should be using a 65mm inlet to it to maximize air flow. That would require I also use a 65mm MAF. Is there any such MAF available? What issues if any will I have with the computer.