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General Forums => The Mess Hall => Topic started by: Dont Know Squat on December 06, 2005, 01:30:28 PM

Title: Is 62mm TB too much for the 2.5??
Post by: Dont Know Squat on December 06, 2005, 01:30:28 PM
I did a search and couldnt find a lot on this. so I am looking to swap the T.B and add a spacer. Is a 62 mm to much ? I have a pretty stock 2.5 with the exception of a "cold air" intake and a highflow cat and dynomax exhaust..anyone done this on the 2.5?
Title: Is 62mm TB too much for the 2.5??
Post by: Jeffy on December 06, 2005, 01:39:56 PM
I do not recommend going with a 62mm unless you plan on doing a lot of other work.  It's too much air for the stock setup and you'll run into problems.  Not to mention if you're planning on buying a 62mm TB, you'd be better off saving your money and going with a stock 4.0L tb for a fraction of the cost.
Title: Is 62mm TB too much for the 2.5??
Post by: Dont Know Squat on December 06, 2005, 02:02:57 PM
thanks jeffy. so what other stuff would need to be done just for conversation sake? hotter spark? different injectors? cam? would it be about like running a carb with too much cfm?
Title: Is 62mm TB too much for the 2.5??
Post by: SMC4WD on December 06, 2005, 04:20:35 PM
I'm running a 4.0L that has been bored out.   I don't remember what is was bored out to, it was just shy of what Rubicon does.

I got my from your buddy (Jeffy), James at Jeepers Creepers in S.F.  

I opened the factory box, removed the reducer tubes with a K&N air filter.  I'm running an AiRaid poweraid TB spacer and a Turbo City MAP sensor.  

As said before...   Teeny bit here and there adds up.
Title: Is 62mm TB too much for the 2.5??
Post by: Bounty Hunter on December 06, 2005, 04:39:34 PM
I think you could get away with it but at a minimum would want an Adj. MAP sensor to dial in your air/fuel ratio.  Then a FirePower ignition setup to make sure all the extra fuel is well burnt.  Index the plugs while you're at it ;)
Title: Is 62mm TB too much for the 2.5??
Post by: SMC4WD on December 06, 2005, 05:10:31 PM
Ya, Ya...

MSD Ignition with blaster coil and Moroso 8mm wires too!   :lol:
Title: Is 62mm TB too much for the 2.5??
Post by: Jeffy on December 06, 2005, 06:55:25 PM
Quote from: "SMC4WD"

I got my from your buddy (Jeffy), James at Jeepers Creepers in S.F.  


Hmm, I'm not sure if I know him.  Did he say he knows me?
Title: Is 62mm TB too much for the 2.5??
Post by: SMC4WD on December 07, 2005, 09:22:34 AM
Quote from: "Jeffy"
Quote from: "SMC4WD"

I got my from your buddy (Jeffy), James at Jeepers Creepers in S.F.  


Hmm, I'm not sure if I know him.  Did he say he knows me?


No...  But since he's in S.F. and you're in the No Cal area somewhere, I had to figure you've heard of him.  His name is James and a guy named Shaun works there too.

He runs a business that's mostly internet.  Primarily caters to TJ's.  I picked up a custom dual battery setup from him, and that bored out TB.  Really a great guy to deal with and talk to.

Check him out sometime.
(Shameless plug here:)
http://www.jeepersandcreepers.com/
Title: Is 62mm TB too much for the 2.5??
Post by: Jeffy on December 07, 2005, 01:40:50 PM
Oh, a TJ'er.  I don't associate them them people.   :wink:
Title: Is 62mm TB too much for the 2.5??
Post by: jeepfourlow on December 07, 2005, 02:11:58 PM
YJ PRIDE
Title: Is 62mm TB too much for the 2.5??
Post by: SMC4WD on December 07, 2005, 04:30:14 PM
I own a YJ too...  

There's something to be said about square headlights!!  

Although if I could do it all over again....    Hummm...
Title: Is 62mm TB too much for the 2.5??
Post by: jeepersandcreepers.com on December 08, 2005, 10:56:47 PM
Hi Guys, We got a few emails concerning the 4.0L throttle body on a 2.5L and I can tell you the 60mm is more then enough for the 2.5L We have had a few people try out the 62mm on the 2.5L and they did not gain any performance but wound up getting a few check engine codes.

We do bore out the 2.5L throttle bodies to 60mm and this will save you from having to purchase a 4.0L throttle body. We no longer bore the stock throttle bodies to 62mm due to cracking of the base. If you really feel you need 62mm, I would recommend a re-designed throttle body and not the stock one because the wall on the stock throttle body tends to get weak and if you add a after market air filter kit with hose, they tend to stress the throttle body and may cause it to crack.

Here's an older link on a bored out throttle body on a 2.5L http://www.gottrail.com/TJ/4.0TB.html

PS: We like YJs and all the other cool Jeeps out there (previous square headlight Wagoneer owner)  :wink:
Title: Is 62mm TB too much for the 2.5??
Post by: Jeffy on December 08, 2005, 11:05:05 PM
I doubt a 2.5L could really see much gain over 54mm without boring out the intake.

Not much wheeling in SF... :wink:
Title: Is 62mm TB too much for the 2.5??
Post by: jwrape on December 22, 2005, 06:53:10 AM
Quote from: "Jeffy"
I doubt a 2.5L could really see much gain over 54mm without boring out the intake.

Not much wheeling in SF... :wink:


Not sure what the stock measurements of the 2.5L TB and the 4.0 TB are but I know when I put the 4.0 TB on, it really made a nice difference in low and RPM rev up. It is one of the best upgrades that I have done.
Title: Is 62mm TB too much for the 2.5??
Post by: Jeffy on December 22, 2005, 11:39:18 AM
Stock 2.5L is around 45mm's while a 4.0L is around 54mm.
Title: Is 62mm TB too much for the 2.5??
Post by: jwrape on December 22, 2005, 12:28:18 PM
Quote from: "Jeffy"
Stock 2.5L is around 45mm's while a 4.0L is around 54mm.


That's still a major difference. I am gonna get some more drimel bits and bore out the spacer and the TB. I did a little boring on the intake already.

Note: Made sure no shavings got into the intake and motor. I am Crazy but not stupid. LOL!
Title: Is 62mm TB too much for the 2.5??
Post by: Jeffy on December 22, 2005, 12:33:33 PM
I still haven't bothered matching the port opening.
Title: Is 62mm TB too much for the 2.5??
Post by: jwrape on December 23, 2005, 05:48:51 AM
Quote from: "Jeffy"
I still haven't bothered matching the port opening.


What all have you done to you 4banger? Just curious. You don't have anything listed in your signature.
Title: Is 62mm TB too much for the 2.5??
Post by: Jeffy on December 23, 2005, 01:33:01 PM
Nothing internal other then taking care of it.  PD Ignition gapped at .060". Performance Carsound Cat-back, Borla Exhaust.  Went back to the stock airbox and Fram Filter.  4.0L TB and a 1" Poweraid Spacer.  This has tuned the powerband a bit higher but still gives me decent power in the mid to high range.  I could have opened up the exhaust more to allow for more top end but then I lose low-end.  It's all about tuning for what you want and not just slapping parts on.  Hard part it knowing where it's going to change things.

I probably should have kept my .440 cam but since I moved to a Emissions state, I didn't want to risk it.