Largest (70+mm?) Throttle body available

Performance mods and Advanced Stroker discussion.
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Largest (70+mm?) Throttle body available

Post by BcurpKodiak »

I'm trying to make as much power as I can in my stroker. 4.7L, 68-235-4 comp cam with 1.7 roller rockers intake, 1.65 exhaust (.506 int/.508 exh). Also running an open header (3" outlet) and I'm even modifying the header slightly. 10.8:1 compression, Russ Pottenger ported eddy head.

I've been thinking about running the 68mm Painless TB. It's actually 70mm or so opening necked down to 68 mm. I've looked into an F&B throttle body for the 4.7L V8 ported to 72mm. But the adapter plate from > > > https://www.tdsideas.com/store/p2/Throt ... ottle.html does not open enough to make sense to try and run the large 4.7 TB.

This was their response: Currently, the bore is 68MM.
If you cut a larger bore to 72MM, it will hit the oring groove if it is centered on the original bore (see the black line).
Also, the bore is not straight down. It angles a little bit to the right as it goes downward.
I forget why it is that way, but it has to do with getting everything to fit on the plate.

Has anyone run a throttle body as large as 72mm or even more? I'm trying to make over 300 HP and for reference the ol' 350 HP LS1 uses a 78MM TB stock. I've already ported the intake to 68mm, could go a bit more.
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Re: Largest (70+mm?) Throttle body available

Post by Cheromaniac »

The 4.6L 3V engine (similar displacement) in my Mustang has a dual 55mm TB (same airflow as single 78mm TB), so you can certainly go bigger if you're aiming for 300+hp.
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Re: Largest (70+mm?) Throttle body available

Post by BcurpKodiak »

ok so I'm thinking about running the F&B 72mm throttle body for the 4.7L V8. http://www.fbthrottlebodies.com/products.htm

then this adapter https://www.tdsideas.com/store/p2/Throt ... ottle.html

so at the very least my smallest part from TB to intake manifold is 68mm. The combo of the adapter + F&B 72mm TB is the same as the Painless 68mm TB. I'd just do my best at porting the manifold and that adapter plate.

I just haven't nailed down exactly what year TB is compatible from the 4.7 V8? And I have to weld on part of the linkage from my original TB onto the 4.7 one right?

Painless 68MM flows: 750 CFM
F&B 72MM flows: "over 790 cfm"
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Re: Largest (70+mm?) Throttle body available

Post by Alexia »

If you are going to start pulling them other vehicles making sure the one you get has a provision for an idle air control motor. The 72mm throttle body without a provision for an IAC I put on my stroker can't idle at less than 2,000 RPM with the throttle at 0.7% open.
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Re: Largest (70+mm?) Throttle body available

Post by BcurpKodiak »

I got a response from Bruce at F&B and they can do a 70MM throttle body for the straight six. This is probably the route I'll go.
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Re: Largest (70+mm?) Throttle body available

Post by arg0413 »

What route did you end up going and are you happy with the results? I just ordered the adapter and a 4.7L 68mm TB for my supercharged 4.0
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Re: Largest (70+mm?) Throttle body available

Post by BcurpKodiak »

arg0413 wrote:What route did you end up going and are you happy with the results? I just ordered the adapter and a 4.7L 68mm TB for my supercharged 4.0
I haven't finished yet, still figuring things out
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Re: Largest (70+mm?) Throttle body available

Post by BcurpKodiak »

Okay so what throttle body would you guys run??

F&B has a their typical 62 and 68mm Jeep 4.0L throttle bodies. If you specify upon ordering they can make the 68mm a 70mm. The response I got was it is 70mm straight through. They don't list flow numbers for the 4.0L TB's but for their other 70mm (4.7L) throttle bodies they list over 700 CFM @ 25"

Painless sells a 68mm throttle body that necks down from 72 to 68 and they list an "affective flow rate" of 750 CFM.

For a maximum power build what would you guys run? Is it believable the painless 68mm flows more than the F&B 70mm?
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Re: Largest (70+mm?) Throttle body available

Post by arg0413 »

I have a dodge 4.7 68MM throttle body with a new adapter to make it work on a Jeep 4.0, I'd sell it all for $140 shipped if you're interested
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Re: Largest (70+mm?) Throttle body available

Post by BcurpKodiak »

Thanks, already received my painless 68mm. Bought a HESCO 68mm TB spacer too!
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Re: Largest (70+mm?) Throttle body available

Post by Tengo86 »

Hey, first post on this forum. I saw that you guys were talking about throttle bodies and thought since i put time into research a few years ago I thought I might share. I've need all the "plug and play throttle bodies that they have out there and me being the cheap-ass that I am I just can't see myself justifying a $200+ purchase for just a throttle body and nothing else. I put around in the forums and on youtube and came across a video where a guy with way more tools than I have made an adapter for a Grand Cherekee/ Durango 4.7L V8 throttle body (TB) that come stock at 68mm and also how to weld the XJ cable hook-ups to the butterfly valve rod on the bigger TB. After I watched that video I wanted to see if that guy or someone else had the bright idea to sell these adapters and I got luck and found it on Ebay for $78 shipped and everything. The company listed was Technical Design Services ([email protected]) and the item name was TDS - Jeep 4.0L Intake to Dodge 4.7L Throttle, Stroker 4.5, 4.6, 4.7, USA Made! After I got it in all I had to do was go to the JY and get one of two of GC/Dur 4.7 TB's (just in case I messed the first one up) and head to the hobby shop on base. Luckily even though I just got off active duty I still had base access which has an auto hobby shop with lifts and tools and a welding station in the back that was part of the hourly fee. All you really need to do is get either a grinder or a Dermal and grind that part of the rod that sticks out past the end of the cable hook-up plate and get a punch and a hammer and because i don't through parts that I get away I had a couple of these XJ TB'c laying around. I think it took me all of a minute or two to grind it down enough so I could drive it through. After that I gut that plastic cable guide off the new TB, lined up the notch that the past went through the XJ cable hook-up to the end of the new TB's butterfly valve rod. When you look at it when you get to this step you'll see what I'm talking about and if you test fit the new TB for reference you really can't screw it up because it needs to end up in the same position that it was in on the XJ TB. Once that's done now comes the tedious part. because you are opening up the TB you need to also open up the opening into the intake manifold. Since I wasn't doing a project that required me to take everything apart and I only had a couple hours after work to do this in or my vehicle would have been locked in for the night I took a bunch of wetish rags and shoved them down into the intake manifold ( yes I counted them to make sure that I know how many need to com out) bolted the adapter plate don and took a sharpie and blackened the entire are that wasn't covered by the plate. Then I took the plate off and used a Dremel as an eraser. After I was done it didn't look pretty but the opening was a lot bigger and with the help of a shop vac and some simple math i was able to make sure that none of the shaving went into the engine. There was only one thing left to do at this point, put everything back together which with the exception of trying to figure out what to do with the map sensor wen pretty smooth. so you know you'll have to pick up a couple feet (just to be safe) of small vac line which is pretty cheap. It's been in there ever since, which looking at the emailed receipt was mid June 2015 and I've had zero issue with it. Your IAC and TPS are the same and have the same mounting. The Map sensor I still haven't permanently mounted yet it's just hangin' out off to the side. There is a vacuumed line post that you will need to cap if I remember correctly because the XJ doesn't have a use for it and the idle air sensor needs to be moved and the spot needs to be plugs which you can get a threaded plug from most places that sell hardware. Remember Fastenal is your friend. Since I had that extra GC/Dur TB I was going to have it ported to 70mm+. I took it to a head shop to try and get it ported and polished but I think the guy misunderstood me. He did a decent job but all he did was knock off the directing notches. he didn't really open it up. That may be my fault because I thought I asked him to pull the butterfly valve and because it's held in with a snap ring that i didn't and hobby shop didn't have the right size to get it out. It's still siting in with the rest of my spare parts so at some point if I get the time and the money to try again to get it ported out but since I haven't done my exhaust yet, and yes I know it's robbing me blind on power and MPG, there is no real rush for me to do it. Once i get that other one ported out though all I'll have to do it swap the rods with right cable hook-ups attached and get a new butterfly valve cut. All in all I think the who thing even though it took some doing i got away for about or maybe even under $100 for the same thing as those "performance" TB's.
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Re: Largest (70+mm?) Throttle body available

Post by BcurpKodiak »

I don't know if you noticed but I linked to that adapter and I had communications with that company. I was just unable to run the F&B 72mm made for the 4.7L V8 on my setup because it would be too big for that adapter (the max size of the adapter was between 68-70mm or something and could not be modified due to an O-ring groove machined into it).

According to flow numbers from F&B their 70mm throttle bodies flow less than the 68mm painless. The painless TB necks down from like 72 to 68 and the F&B is straight through. I asked Russ about this and his response was "Think of a throttle body as you would a Venturi or a booster a carburetor. Shape is as important as size."
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Re: Largest (70+mm?) Throttle body available

Post by Sailboy42 »

Is there a disadvantage to running a larger throttle body? I would think at some point you would get turbulence that would mess with the flow.
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Re: Largest (70+mm?) Throttle body available

Post by Cheromaniac »

The only disadvantage is that the throttle response could become too sensitive like an on/off switch. You'd need to enlarge the intake manifold plenum opening from the stock 62mm to 70mm so that it matches the TB size.
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Re: Largest (70+mm?) Throttle body available

Post by Sailboy42 »

So when people put TB over 62 they have to modify the intake manifold?. Does that mean custom gaskets?
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