As the winter season aproaches, our cars now have the task of starting in this cooler weather. I was planning on doing the "tb mod" as well as remove the EGR and Air Bypass Solenoid Valve, but I was wondering everyone's experience was with theses mods and cold weather... I know this has been discused before... I just think it would be good to get an update how everyone's moded car is going in this season's cooler weather. I really hate AWS and want to get rid of it, so long as it won't be a bear to run in the cold weather. Another small concern I have is with having the secondary plates removed. How is throttle response affected?



Thanks!

 

My car is the most cold natured vehicle with fuel injection I've ever seen. I can not crank it in the morning and walk back in the house. But as soon as it warms up a lil its fine. Thats about the only problem. The TB mod I did is great, I'd recommend it. Its a lil touchier in traffic at first, but once your used to it its fine. Its not a bad kinda touchy, its just better than what your used to.
Keep in mind I believe my tp sensor is bad. So someone else may want to chime in here about their setup.

 

Thank you for your reply. Right on topic and informative. I hope you can get your tp sensor probs worked out.

Thanks!



Keep the info coming guys!

 

The AWS has got nothing to do with making the car start or run better when cold. It's purely there to warm up the pre-cat quicker to reduce emissions. Removing it will have zero effect on cold-weather behaviour (other than removal of the annoyance). You'll be doing your engine a favour by removing it.

The TB mod is one of the most misunderstood topics on this forum. There are two totally seperate parts to the TB mod: the removal of the double throttle system and the removal of the thermowax. You don't have to do both!

Removing the thermowax will result in an engine that won't idle cold no matter what time of the year (unless you jack the idle speed up high to compensate). IMO it's a pointless mod whose disadvantages outweigh any advantages (whatever they are).

Removing the double throttle system improves throttle response on Turbo engines but works differently on NA engines and removing it has no effect on throttle response (except maybe in your head).

 

Good point. I just hate the thought of a cold engine shooting up to 3000 rpm on startup. The thermowax isn't as offending. I think every car has some kind of fast idle system these days(yes, and even AWS ... ). I just want to know what others have experienced after removing it, as well as/or the secondary plates. Has anyone actually done some timed testing or dynoing before/after? I remember reading somwhere about someone claiming they increased flow 30+% by just polishing the plate edges and also machining the back of throttle shaft down.

 

yeah, i hate it when my car starts cold and revs to like 3,000 rpms before oil pressure is even available. I read that if you start the car in gear with the clutch pedal down it will prevent this from happening, but in my own experience this hasn't always proved true. I don't see how it could be an inconsistent thing, my turbo II would rev to 3000 unless i started it in like 1st gear. btw if you live in southeast USA you probably shouldn't have trouble with the cold adapted stuff, i think it is mostly for much colder climates.

 

It bearly gets cold down here in the "winter" months. I've only been here a few years and the most snow we've had was like 2"! It's crazy how many accidents happen when there is a little ice/snow on the road... I may go back up north some day, so I don't want to undo something on my car for it to operate in the true winter conditions of upstate N.Y. (10' banks of lake effect snow, -20deg... couple bags of rock salt and a shovel in the trunk... Oh yeah!)
So it looks like I'll keep the thermowax for now...

 

Well.. I have a TII with a Haltech.. and part 3 of the two part TB mod that NZ mentioned... I actually hogged out the interior of the TB and polished it after removing the dual throttle plates..... Cold or hot, its a bit blippy, but, you get used to it quick.

I somtimes wish i hand't removed the thermowax.. BUT... and this is a BIG but.... it makes taking the UIM off a freakin SNAP... putting that stupid coolant line on the bottom of the manifold back onto the block everytime you take the UIM off SUCKS, causes MAJOR frustration and tools to FLY around the garage...

The Haltech helps a bit, you can monkey with the coolant and air temp maps and get it pretty smooth. But, right now, I have the BAC workin at 1500 RPM until the car hits 150F on the water temp. The BAC doesn't start right away, it takes about 30 seconds for it to kick in, "sometimes a LOT longer, seems that the haltech opens it up whenever it gets around to it....

BUT, you know what... I'm in the process of making an adapter to hook up a manual choke to the Cruise control linkage that will serve the same purpose as the thermowax, just crack that baby open a little bit when the cars cold to let a little more air in, then, maybe i can ditch the BAC!!!! (which is loud and annoying and as mentioned before, the Haltech seems to think of it as a Go-to girl)

I've also moved my filter back onto the end of the turbo and ditchs the CAI for the winter, my Air temps the other night were SCARY low, and that helped it out.

 

Umm.... Yeah.... I bet he really put it on a flow bench too...... 3% i'd buy..


You wanna get more flow out of the stock TB.. Gotta do this...



there's a LOT of metal that can be removed after you get rid of the dual throttle plates and a LOT of flat edges that can be sharpened to points!!!!!

Still.. I doub't iits 30%., but, its possible, however, you STILL have the same size throats... you've just easing up the flow before it gets to the plates..

 

Very interesting read. You made a good point about the ease of removal/installation when the thermowax is gone. That is one shiny TB too! It would be interesting to find out how much hp the mod has added in peoples cars. (turbo and N/A)
As NZ stated, having the secondary plates removed is more beneficial when done on a turbo, and probably doesn't do much good for the N/A.(one exception could be on a compitition car which doesn't spend much time below 3000rpm?)
I'm in the process of building a flowbench, so hopefully I'll be able to see definitive results(i.e. what % of an increase in flow) when I mod and port/polish the intake. I sometimes wish I had a turbo, but then my project would probably take twice as long and cost twice as much.

Thanks again for relaying your experience with the TB mod.

I sure hope to hear from some more N/A guys out there too!

 

 

Have a look at this photo. This is my UIM immediately after reconnecting the coolant hose prior to reinstalling the UIM.



You can see how accessible the hose is. The tricks to making this a quick and easy job are to remove the rubber TMIC elbow from the TB (so you can postion the UIM as shown), replace the stock squeeze clamps with screw clamps (much easier to loosen and tighten using a screwdriver or socket rather than pliers), and put a little spay lube on the TB connection (so the hose just slips on). The only real hassle is draining and refilling the cooing system, but IMO this a small and very infrequent inconvenience compared to a crappy idle every time you start cold.

 

In reviewing everyone's input (and other sources), I have come to the decision to keep the thermowax and secondary plates. This, to me is the most logical.
For now I will port/polish and machine the throttle shafts down.(AWS valve is already history )
Modding is best done in steps anyway.(How many times have we heard that?) That way, it is easier to assess the affects/stresses putt on the various other systems. The point at which some other part/system can no longer fuction properly is difficult to find, and crossing it means making even more moddifications, or worse...undoing what you did.
The main things to consider are the unexpected glitch, malfuntion, falty operation, or lack of operation that a specific moddification could produce under the many different conditions a street car could possibly encounter. In this case I am most concerned with cold idle problems.
If I was building a pure compition car, then things would be very different...


Thanks again everyone for the helpfull information.


Trueblue707

 

Y'all are forgeting part of the function of the AWS (Air Bypass Solenoid Valve). Each time you go to START, the BAC and the AWS (Air Bypass Soleniod Valve) go full open. Wide open. Full open. All the darn way open until the key is released (I'm not including the 17sec here).

That explains why some who have removed the items find that they can push the pedal til they feel resistance and hold it there, then start the engine. They are simulating the BAC and the Air Bypass Solennoid being full open.