GinDistiller

Does anyone have an 80mm throttle body laying around after going bigger? My car is one of the unlucky ones that just doesn't like the 82, and I don't want to pull the SC to port again for larger.

The talk and availability around these seemed to die when the 82 became popular, hoping someone has one collecting dust. Let me know!

lost27

This is a bummer to hear and I fear I may be coming to the same conclusion. If I have to remove my 82mm (which is BRAND NEW OEM) I'll for sure be going with another brand new OEM 80mm. Yes it is expensive but I've had such a bad experience with used throttle bodies that the cost far outweighs the potential for headaches and time.

GinDistiller

Ugh I know. I have theories, which may not be worth much but will post shortly in my other thread.

lost27

Will the 80 bolt right to the port or are you running one of those 82mm adapter plates?

GinDistiller

I've combed through all of the 80mm threads (which are years old at this point) and can't find a definitive answer as most people where buying the SL snout too. I have the adapter for the 82, so if I find one I'll make it work somehow either modifying the adapter or tapping offset holes in my snout.

bobgodd

https://www.ebay.com/itm/Dodge-Chrys...-/123609570678

This is 80mm, and looks extremely similar to ours. Want to be a trail blazer and figure out if it works?

GinDistiller

Oh heck yes. I just ordered a low mileage takeoff, $33 shipped. Looks like it opens the same way, I'll see if I can find a connector end for it and see where the mounting points align. I'll probably grind down the inlet, that looks to be too long and would push the y-pipe too far back, but that's easy work.

It's coming in a week, so give me 2 to get it fabbed up!

lost27

Don't forget you might need to drill a hole for the vacuum line that goes into the OEM throttlebodies.

GinDistiller

Yep, although I may tap that in the intake depending on how much clearance this TB gives, we'll find out!

SICAMG

Correct on there not being a hole. I drilled mine and cloned it to the factory throttle body. Also I never used an adapter....just oblonged the bolt holes on the throttle body and it worked perfect.
Mercedes 80mm's open in reverse so you will have to swap pins if you use it....real easy.

oneslow55

80 vs stock is not a huge difference ,I had both didn't really see a difference.

AgSilver

If you port an 80mm it's pretty close to 83mm

GinDistiller

Probably because it's really a 78, so I'm curious to see what a true 80 feels like. I definitely felt a difference with the 82 (when it was running right). Mostly I don't want my work porting the snout to go to waste haha, it just seems cruel to have done that and now run a stock TB. I'm pretty proud of my carbide cutting skills.

oneslow55

Yea ,pretty much the issue.The tb is not much larger i would personally use a hellcat size for good gains.

lost27

If (big if) the issue is that the 82mm is allowing for too much air to pass through when closed and the computer can't compensate, how would going to a larger throttlebody be any better?

oneslow55

That's not true as many installs have leaks they don't think they have .The larger tb work great as it's tune related and i never had a missed beat with it..Tune is key along with proper installation .

GinDistiller

I know my post might seem misleading, but I don't think the issue is 100% based on there being too much air, just too much air for that specific throttle passage. I can confirm I had no install issues or leaks, simply going back to stock was enough but I has thoroughly 3-bonded the adapter plate, did smoke testing, carb spray etc and have not changed anything else. I also wonder if there are any mechanical differences between the N/A and forced induction TBs. The 80mm and Hellcat both are forced induction, the 82mm is off an N/A motor. All of this stuff would require a ton of side by side testing to verify, but I do find it quite interesting that the 82mm seems 'cursed', SO many people with issues yet a lot of those same people found a different size was just fine and I doubt they drastically changed their installation approach.

In another life when I managed an independent repair shop, we saw a lot of repairs but it was very rare a throttle body went bad. The 82s are bashed on because most people buy used, but it's such a rarity for them to fail I just can't wrap my mind around there being a ton of bad, Genuine Mercedes TBs floating around off of wrecked E550s etc. It seems more likely the velocity, airflow, and vacuum readings that size gives off is enough to trip the MAP and ECU settings on a lot of our cars, and I'm sure it drives some tuners crazy too since most tune for closed loop and this stuff is left to the factory manipulations.

SICAMG

I picked up 1 lb of boost from the stocker to the 78 with shaft grind. 16.0 to 17 lb roughly.

redc36

you dont need to drill if you want to keep oem.
SL55 (07/08) comes with a different crankcase vent hose that plugs differently and works with 80mm TB + oem 80mm snout

lost27

True if you're using the OEM 80mm snout, some folks are running the ported OEM 74 snout I think and in that case they should be aware of that subtle difference. Good point though

redc36

if 74mm snout used then just break the plastic plug and route it there. thats how 80mm sl55 snout works. I bought it new

GinDistiller

That's a great point. I removed mine and replaced with a rubber plug sealed w/ rtv to eliminate issues of that plastic piece breaking but I'll tap into that for the pcv.
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The 80mm Jeep TB comes today, hoping to get it fabbed up and tested next week!

GinDistiller

Well no guinea pig work for me, that Jeep TB is basically the same as our stock TB, not sure why it was thought to be 80mm. Measures roughly 74mm, and the butterfly is even stamped with the same number as my stock one. Holes line up too. So I guess this is a cheap alternative for a stock TB. I'm only out $30 so I'll see if I can resell it.

BUT, I mentioned my earlier gripe about the stumble when the car wants the SC clutch to engage - Tony sent me a new map that completely got rid of it, so I'm a happy camper! Basically it's driving perfect now, especially with zerocat's latest TCU tune, so I'm not touching it anymore. I promise? Unless someone does come up with a good deal on a used 82mm and then maybe I'll do the switch, still looking.

lost27

Do you mean 80mm? I thought you were having problems with the 82. I'm curious what Tony changed to get you up and running again.

GinDistiller

Yes, typo, I already have a used 82 paperweight haha. I think for now I may have a go at a shaft grind and polish of my stock TB since it's free and I have the equipment.

Whatever Tony did, it had to do with the clutch engagement programming as my problem happened precisely when the ECM switched to 'engaged' on the SC clutch (even though I'm on a fixed pulley). I haven't logged again since the fix but have a suspicion I might not see the clutch as un-engaged as it was before. Or it had to do with bypass valve timing as I think that is what changes when the ECM thinks it's engaging the SC clutch.