Modified Thermostat for higher MPG's... - Page 5

josh8loop · March 8th, 2011, 16:47

DF,

I found that the coolant reservoir was about 2 maybe 3 degrees cooler than the outlet flange. Pretty close IMO. Are you running radiator block offs? I just blocked mine off this evening to see if I can get a little higher temps with my 195 deg T-stat before experimenting w/ the other one.

dieselfuel · March 8th, 2011, 22:45

Yes, I am, pipe insulation. I really don't think it makes much difference, to tell you the truth. I actually forgot about it til you mentioned it.

Maybe using cardboard up against the radiator might work, but that would block airflow. I'd rather not block airflow.

I'm sure inside the block the coolant is 190F, at least. So, again, if we could get 200-205F, at least, in the tank, that would be great.

Remember, Evans was talking about raising the temp 20F more than stock. So, that puts the TDI at 210F.

Also, those ARP 2000 studs for the TDI are about $199, but Kerma may have them for $159. They were on sale. I'll have to check.

df

dieselfuel · March 14th, 2011, 16:18

Josh,

Everything going o.k.?

I just ordered the ARP stud kit from Kerma. When I get time to install them, I will. Hard to find a time when the TDI isn't being driven. :>)

josh8loop · March 15th, 2011, 06:39

DF,

Everything is fine, thanks. I have been doing some minor maintenance activities on the TDI as of late that I wanted to get straightened out. Namely I am replaceing the fuel lines in the engine compartment. I have installed a small clear teflon section so that I can see air bubbles in the fuel lines. It is looking really nice. I found some fuel line fittings(quick disconnect Elbows) from a 1.8T Jetta and used weather head(cloth covered) 5/16 fuel line. It looks really nice, and looks like it was meant to be there. I have also installed some engine cover pop fasteners-it is really nice to quickly pop the cover off when needed.

I was experimenting with partially blocking the radiator to see how the engine operates at elevated temperatures. I found out my T-stat I have now(195) doesn't seem to be functioning properly. I was able to get it to about 200-205 degrees with the blockoff. I want to be carefull since my transmission is cooled by the engine coolant, and I am not sure how it will respond to the 205 degrees.

dieselfuel · March 15th, 2011, 08:20

What did you use to block off the radiator.... cardboard? How did you install it...?

I'd like to get rid of my pipe insulation and go with another solution.

josh8loop · March 15th, 2011, 10:11

DF,

I used rubber matting from an old ergonomic floor standing mat I had laying around. I cut it to approximately the width of the radiator, and slid it up under the front valence directly contacting the front of the radiator. Have you seen the Ford commercial on TV that shows a car with moveable louvers in front of the radiator-I think it is the Fiesta. Neat for sure.

dieselfuel · March 15th, 2011, 13:25

O.k., and how does it stay against the radiator and aren't you afraid it may melt?

josh8loop · March 15th, 2011, 16:00

DF,

The foam is about 2" thick, so when you pass it through the lower valence and start vertically in front of the radiator it gets held in place between the radiator and a horizontal cross member about half way up. I'm not concerned with meltage-this is the same stuff I remade my engine cover sound deadening with. It has been fine for a month or so on top of the engine.

The only bad thing about the radiator block is that any air that would need to be passed through for the A/C condenser would be blocked which could cause higher than normal A/C pressures. Also, you are gambling that the unblocked portion will be able to sufficiently reject enough heat to maintain engine temperatures. The weather here has been cool one day, and hot the next, so that makes it a bit tricky for me. I mainly used it to see if my mileage went up, and to see it the T-stat was working properly. No numbers yet.

Honeydew · March 15th, 2011, 16:59

Josh, give me a call and come by the shop. I'll loan you my vag-com plus an old laptop to run it if you'd like. I forgot about the laptop when we spoke last week, I was driving a rental suburban in Alabama during a downpour trying to follow someone to our destination.

josh8loop · March 16th, 2011, 04:43

HoneyDew,

Will do, greatly appreciated. Nice talking the other day by the way.

dezeljunky · March 20th, 2011, 02:09

What does the extra spring on the TDI thermostat do compared to the regular gasser thermostat? Sorry if it's been asked already.

josh8loop · March 20th, 2011, 05:25

Diezeljunky,

That spring is there to allow the rear disc to seat in the bypass opening in the block while still allowing the thermostat to continue opening. If it was a single piece, the disc would seat and the thermostsat opening stroke would be limited.

dieselfuel · March 21st, 2011, 19:23

ARP head studs are in and o.k. Got it up to operating temp and ran it HARD up to 80 mph in gears 1-4 and just put it in 5th and cruised home. Got back, popped the hood and nothing leaking. Everything looked and seemed fine. :>)

josh8loop · March 22nd, 2011, 04:35

DF,

Good, glad to hear it went well. Let us know how the mileage side of things goes.

dieselfuel · March 26th, 2011, 12:11

Josh,

Just filled up, and there was no increase of mpg with the ARP headstuds installed.

I was within .07 mpg of my prevoius fill-up with the stock headbolts.

I guess if someone had a gasket leaking coolant, their mpg would suffer over time. Installing the ARP's would give better sealing and hence restore their mpg.

There's no way, imo, taking a healthy engine such as mine, and installing ARP headstuds and getting higher mpg. Not even ARP would make such a claim, lol!