Big bore throttle body (1 Viewer)

[Spook50]

Has anyone installed one of Downey's big bore throttle bodies in their FJ62? I have a spare TB that I can have bored out to the 3" that Downey offers, and was wondering if it's worth it. Downey recommends adjusting the MAF to better take advantage of the extra airflow, but the thought of doing that makes me a bit leary.

Also, are their any other good ways to manually control the mixture on an EFI engine? Something that may be adapted to our rigs perhaps?

 

[Tinker]

Spooky -
Being as this is a system, does it make much sense to mess with just one part of it? If it's in balance in the stock mode, increasing the throttle body bore would put it out of balance. If you had changed cams to something with a longer lift and/or duration on intake, (& would probably need it on exhaust, consequently), you might need to increase the throttle body bore to get the extra air in & put it back in balance.

Are you looking for bottom end torque or top-end horsepower? In general, bottom end torque requires a smaller, longer intake tract. High end horsepower requires a larger, shorter intake. Modern engines get torque over a wider range by varying cam timing & lift & intake path.

 

[dd113]

Tinker is right on. The thing is, every one I have ever known that did a bigger bore on a 3FE or a 22RE raves about it. I will do it eventually. Dont buy from Downey. Go to the 3FE list and search for info.

 

[Tinker]

David -
Enlighten us: why not Downey?

 

[Spook50]

Tinker is right on. The thing is, every one I have ever known that did a bigger bore on a 3FE or a 22RE raves about it. I will do it eventually. Dont buy from Downey. Go to the 3FE list and search for info.

Yeah I've got my spare that I'd take to a machine shop here to have bored out and have a new butterfly valve made for it. I tend to agree with Tinker's points. Be cool if we could get a longer intake runner for our manifolds (lemme rephrase that; be cool if we had the underhood space for it) where the fuel injectors go.

I'd love to get the big bore throttle body with an RV cam from Clifford. My biggest wish would be to get my cylinder head ported and polished, then get a set of headers and a tuned and balanced intake manifold. Bit too expensive for me though, especially at this point in my life.

 

[Tinker]

Spook -
Have the whole mess scientifically ExtrudeHoned instead of the old-school black art port-and-polish. Balances the flow between the cylinders. No idea of cost, however.

You realize it's cheaper & easier to go to a SBC than hotting up a 2F.

 

[Aseif007]

Spook50,

Can the ECU on the 3FE handle the RV CAM? I was under the impression it couldn;t. My ECU is barely handling the higher compression. I found a place near me that would re program my map, but I think that is a little extreme for my race-tractor motor . Also they want $900!!!!!!!!

 

[overhanger]

Overboring TB

I've installed the RC Engineering overbored TB with great improvments realized. For the long version, go to the 3FE list for discussion or search the 3FE list archives through birfield.com's search engine - it is much more efficient than the Yahoo search mode. Short version is that, with an engine rebuild, milled, ported and polished head the overbore brought out the best of the engine work. I didn't install the TB until a year after the rebuild so had a before/after experience to quantify the improvement. Someone on the 3FE list has installed one on a stock motor but hasn't said much about it. The reason to bypass Downey is because it was determined that RC Engineering, of injector balancing fame, does the work and takes orders directly from private parties. This work isn't mentioned on the RCE website but give them a call for particulars and save a few $$.

 

[Spook50]

Spook50,

Can the ECU on the 3FE handle the RV CAM? I was under the impression it couldn;t. My ECU is barely handling the higher compression. I found a place near me that would re program my map, but I think that is a little extreme for my race-tractor motor . Also they want $900!!!!!!!!

Supposedly it can. I've heard that some have installed Clifford's RV cam and had great results with it, though I've never actually spoken with anyone who has. I wish reprogramming our ECUs was easier to do ourselves. I'd be willing to bet that you could get assloads more power on both the high and low ends with a few programming tweaks here and there.

Tinker: I'd give my left nut to have that done on my rig. Someone on the 3FE list back in the day mentioned a guy in Van Nuys (SP?), CA that did all that and had an incredible increase in overall power. Probably be way beyond what I could afford though

 

[pappy]

Has anyone installed one of Downey's big bore throttle bodies in their FJ62? I have a spare TB that I can have bored out to the 3" that Downey offers, and was wondering if it's worth it. Downey recommends adjusting the MAF to better take advantage of the extra airflow, but the thought of doing that makes me a bit leary.

Also, are their any other good ways to manually control the mixture on an EFI engine? Something that may be adapted to our rigs perhaps?

-----------------------------------------

I'm one of those guys that's done this to a 22re. I think it works well. Motor is balanced and the head ported/polished with a cam, so the demand is there. As far as adjusting the AFM, it's not hard. Just cut the cover off and move the gear counter-clockwise a few teeth. Personally, I question whether it needs to be done at all, though mine is 1 tooth rich.

Your last questions is a possible yes. There is an adjustment on the AFM. I know it's there, but not familiar enough to say how it works. I do know it can help with emission issues. It's plugged, so you can't get at it. It's best messed with by somebody that knows what there doing.

 

[Tinker]

Spook -
Save it up for an eventual rebuild - you could even find a dead block (I had one 6 mo ago) & start amassing parts. Remember, time & money are interchangable. Overhanger's engine sounds interesting - there'd be considerable merit in hotting up a 2F if you could get the torque curve you want, assuming it didn't cost more than a SBC. Probably due to religion, I guess. RC Engineering is the real deal, according to my Audi mechanic buddies.

Had to use the stock '83 60 to get out of our driveway this morning - 3-4' drifts: the Vortec 60's in the shop getting the remaining details taken care of. The 2F is more tractable in deep snow, even though it only has 31" Wranglers & the Vortec has 33" MTRs. Someone on this board mentioned "low-speed 'bumpability'" - the ability to back off the throttle while crawling & just bump it to get over something. That's what the 2F's great at!

 

[Aseif007]

Is there anyone that has an RV CAM in thier 3FE right now? When I was talking to Man-A-Fre a couple of years ago they said that the ECU wouldn't be able to hadle the RV cam and it would run a little rough, and definatly not pass smog. I just want to know if anyone is currently running an RV cam with success.

 

[Spook50]

Is there anyone that has an RV CAM in thier 3FE right now? When I was talking to Man-A-Fre a couple of years ago they said that the ECU wouldn't be able to hadle the RV cam and it would run a little rough, and definatly not pass smog. I just want to know if anyone is currently running an RV cam with success.

Those were the same symptoms I've heard it would have, but I've been told that it's just a rough idle and that that's not due to the ECU. Sure would like to get my hands on one though. I'm clueless on how to degree in a cam though, so that makes me hesitate.

 

[Aseif007]

Would the RV cam that MAF sells for the 2F go into a 3FE? And would we even want to put it in because I thought since the valves may be opening at the same time, due to the cam, it would make the motor less efficeint at low RPMs?

 

[Spook50]

Would the RV cam that MAF sells for the 2F go into a 3FE? And would we even want to put it in because I thought since the valves may be opening at the same time, due to the cam, it would make the motor less efficeint at low RPMs?

I don't think the 2F cam would work in a 3FE. Don't quote me on it, but I believe the valve order is different between the two heads, along with several other differences. This is just trying to remember what I've been told though. I'm honestly not sure of all the differences between the two.