TB Hot water bypass

[JerryCS]

Ed, sounds simple enough to bypass the throttle body in spring and reconnect in fall if you live somewhere like... Wisconsin.

Jerry

[F8L]

Originally Posted by edthefox5

Hi,
Down here in Fla mid summer it really helps whatever the dyno says. Its a very common thing. If you don't believe me just Google "Hot water bypass". Its a must do for Ford Ranger trucks for instance to stop pinging. Not sure why there's such a negative response here. It's no big deal.

Like I said, my negative response is based on actually having done this mods on numerous cars and not seeing any benefit whatsoever. Your SOT (seat of the pants) guage are typically pretty well useless in an instance such as this.

I'm not saying you shouldn't post the info for it may make a difference on these cars and in certain climates but since my experiences have been different I will post the "negative" response to the idea to keep things in perspective.

[bruceha_2000]

Originally Posted by edthefox5

But as mentioned earlier automatic valve aside this mod would have a negative effect in the cold icy Vt winter. You would need that TB de-icing up there for sure but like I said before this is strictly a regional thing.

As you know, it can get pretty toasty up here in the summer. Not like Florida, Nevada, etc toasty (toasted??) but 80's and 90's are quite common.

That is why I figured a thermostat based automatic system would be best. It wouldn't bypass in the winter and you wouldn't have to remember to disconnect/reconnect seasonally Plus, it would provide the most efficiency if the computers can be programmed to figure out exactly what the prime temp is to bypass.

[edthefox5]

Got my Scan Gauge today..hooked it up and it works perfect right out of the box. Concerning my TB mod the temps I saw were pretty much what I expected. During a highway 20 mile commute today with outside temps at 60F the block water temp hovered around 185-190 with the intake temp at exactly outside ambient temp around 60 f. Thats a 120 degree difference.
The intake was cold to the touch when I arrived. The intake temp spiked a few degree's when I hit stop & go but the minute you rolled it archieved outside ambient. I do not expect any performance increase now but I assure you during the summer the car really enjoys it no matter if this performance cannot be seen on a standard dyno test. During the summer when outside air is 90+ and the block water temp is 200 I expect to see at least a 120 degree cooling difference between block & intake. In a car that has a CAI & performance muffler the difference is dramatic no matter what anyone says here. Maybe your testing a stock car? My last mild performance car had a CAI & headers and power tuned timing. It had a tiny bog when I punched it. After this mod no more bog. A dyno cannot replicate outside 70 mph wind cooling the intake and a dyno cannot replicate real life drivability improvements.All a dyno measures is max horse & torque numbers. Thats not always the whole story.

P.S. Sorry about the pics..I took them while rolling.

[ken1784]

Originally Posted by edthefox5

Got my Scan Gauge today..hooked it up and it works perfect right out of the box. Concerning my TB mod the temps I saw were pretty much what I expected. During a highway 20 mile commute today with outside temps at 60F the block water temp hovered around 185-190 with the intake temp at exactly outside ambient temp around 60 f. Thats a 120 degree difference.

OK!
Your intake temp was same as the outside temp.
Your water temp was around 185-190.
Then, please let us know your intake temp without your mod.
We can't agree "Thats a 120 degree difference" unless we hear your intake temp without your mod.

Also, how much power or mileage number did you get from your mod?
We would like to see a dynamometer test numbers.

Does anybody agree?

Ken@Japan

[edthefox5]

Rolling not sure as I did not have a Scan before I did the bypass. I did once measure it with my laser thermo and I thought it said 116.

[F8L]

Originally Posted by edthefox5

In a car that has a CAI & performance muffler the difference is dramatic no matter what anyone says here. Maybe your testing a stock car? My last mild performance car had a CAI & headers and power tuned timing. It had a tiny bog when I punched it. After this mod no more bog. A dyno cannot replicate outside 70 mph wind cooling the intake and a dyno cannot replicate real life drivability improvements.All a dyno measures is max horse & torque numbers. Thats not always the whole story.

Actually I've done the mod on stock LS1 equipped F-bodies and 5.3L trucks to a heads/cam/nitrous'd LS1 (11.12@123 ) in the 1/4mile) and a 5.3L turbocharged truck (550rwhp then 717rwhp). My buddy's dyno (DynaPack) can replicate real world driving conditions fairly closely and under any load he chooses to put on the car and at any RPM and throttle position (IE not just max HP/TQ at full throttle. Most dynos use a large fan to simulate wind flow through the engine bay. The point is, I'm deifnately not a noob when it comes to making HP. I've been drag racing Mustangs and LSx-based engines since the early 90s.

My first race engine used this mod back in 1996. I could never tell a difference but it kept me from leaking coolant everytime I removed the TB so I kept the mod. Notice the two tubes on either side of the TB have no coolant lines on them?

All I'm asking is for you to provide the members of Priuschat some kind of quantifiable evidence to back up your claim before they risk a fuel milage decrease or altering emissions.

[BT Tech]

I have done this mod on a number of LSx based corvettes including my own and it is worthwhile and costs next to nothing to do.

As the OP has pointed out correctly, the purpose of running the heated coolant through the TB was to decrease any chances of the throttle sticking during severe cold weather which btw is NEVER a chance here in South Florida!!

Anytime that you can lower your intake ambient temps (IAT) this is a good thing as it will most often result in slightly higher hp/tq and reduced chance of detonation occurring.

IMO this is a great mod for near little cost and effort....

Great post Edthefox5!!

[Pinan]

Originally Posted by edthefox5

Rolling not sure as I did not have a Scan before I did the bypass. I did once measure it with my laser thermo and I thought it said 116.

FWIW. I checked today (mod not done) and when the WT was at 184°, the IAT was 80°. This at an outdoor temp of about 70°.

Upper grill blocked. Measured with SG2.

[edthefox5]

Originally Posted by F8L

Actually I've done the mod on stock LS1 equipped F-bodies and 5.3L trucks to a heads/cam/nitrous'd LS1 (11.12@123 ) in the 1/4mile) and a 5.3L turbocharged truck (550rwhp then 717rwhp). My buddy's dyno (DynaPack) can replicate real world driving conditions fairly closely and under any load he chooses to put on the car and at any RPM and throttle position (IE not just max HP/TQ at full throttle. Most dynos use a large fan to simulate wind flow through the engine bay. The point is, I'm deifnately not a noob when it comes to making HP. I've been drag racing Mustangs and LSx-based engines since the early 90s.

My first race engine used this mod back in 1996. I could never tell a difference but it kept me from leaking coolant everytime I removed the TB so I kept the mod. Notice the two tubes on either side of the TB have no coolant lines on them?

All I'm asking is for you to provide the members of Priuschat some kind of quantifiable evidence to back up your claim before they risk a fuel milage decrease or altering emissions.

I don't care how many hot rods you own you still don't know what your talking about! Woo Hoo!!! Just kidding! You sir are a serious horsepower dude. I no longer feel qualified talking hop ups with you! I kinda agree with you. There has not been much if any performance improvement other than what I think I'm feeling in various portions of the power range. The car
doesn't not like it though. I'm still hoping for some improvement in the hot deathbed of Florida summer but I gotta tell you that my big problem here is the Prius is a very bad test bed to get any performance improvement from.
Case in point: Based on what the other poster said about re-directing the intake tube I took that step further and on a lark disconnected the intake tube from the noise deadening box. So it had the nozzle of the air cleaner box open. All filters intact though. The car did not like it. It ran ok but when you stepped on it it bogged and stumbled a little and man oh man was it loud. For a 1.5 it made quite a loud 4 barrel cracked open sound. Not in a good way.So the other poster was right too. That little motor is sucking some air volume when you open it up.So my conclusions are that it will be hard to do a simple small horsepower improvement to this car. Its maf /fuel map is very strict. Any intake improvement would have to be accompanied by a new fuel map software chip. Which would be hard to write given all its weird parameters and the fuel economy would be a throw away.Other cars I have owned responded so much better than this car to a bypass. There's some performance in this little motor I bet but at great expense to fuel economy I'm sure. So thanks alot for educating me. I'm going to leave my bypass on as its not hurting anything and bottom line it can't be good to have 200 degree coolant flowing through the TB during 100 degree summer heat.