correct value for warm CHT reading (ohms) Options

[brant]

so my CHT reading was 76 ohms - hot (at 180F oil temp)
I'm reading 2 different things.. on the Brad anders site


one saying that a warm reading should be below 100 ohms
but then the table shows this: for 210F

Sensor Temp = 39 deg. F Temp = 61 deg. F Temp = 210 deg F

0 280 130 003 6.10 K ohms 2.94 K ohms 199.3 ohms
0 280 130 012 NA 2.85 K ohms 191.2 ohms
0 280 130 017 3.63 K ohms 1.74 K ohms 124.7 ohms



I'd love some input from Djet folks about what numbers you see on a warm motor?

brant

[brant]

New Bosch sensor
New calibration

Fine at idle
Mid to High 12’s from 3k to 5900 rpm

A bit lean. But not much..? At light throttle... highway cruising 80-90mph steady for multiple miles
13.7 to low 14.0. It starts out better but steadily climbs over a mile or two...to that number

I’ll have to research more
What is your goal for steady light throttle?

Oh. And my head temp gauge is now working for no apparent reason
I took the thermo ring out last night for visual inspection. Now it works

[JamesM]

WOT numbers sounds pretty good, especially if you are still holding in the 12s under load at 5900RPM

Are you running a stock cam? All my stock cam cars are done making power well before 5900.

When im tuning Megasquirted cars I usually have the AFR targets set mid 12s under load and mid-high 13s cruise, though i have suspected i could probably lean out the cruise area a bit more. I usually try to keep it out of the 14s unless in overrun but with the thin, hot, dry, air in salt lake I try to error a little on the rich side to help the head temps.

If your head temps are good I would say your numbers are fine.


Around here with my 2.0 d-jet cars (that do have temp monitoring) its not uncommon
for me to see 380-390 (depending on the day) at the #3 plug pushing it on the freeway.

My cam'd high compression 2056 Megasquirt car usually runs ~50 deg cooler

[brant]

WOT numbers sounds pretty good, especially if you are still holding in the 12s under load at 5900RPM

Are you running a stock cam? All my stock cam cars are done making power well before 5900.

When im tuning Megasquirted cars I usually have the AFR targets set mid 12s under load and mid-high 13s cruise, though i have suspected i could probably lean out the cruise area a bit more. I usually try to keep it out of the 14s unless in overrun but with the thin, hot, dry, air in salt lake I try to error a little on the rich side to help the head temps.

If your head temps are good I would say your numbers are fine.


Around here with my 2.0 d-jet cars (that do have temp monitoring) its not uncommon
for me to see 380-390 (depending on the day) at the #3 plug pushing it on the freeway.

My cam'd high compression 2056 Megasquirt car usually runs ~50 deg cooler

Absolutely not trying to be negative

I hope you have a cooler on those cars
Those are pretty high head temps. I typically run 300 max. But have seen 340+ a hair
(On the track worse)

I have a long standing theory. That the Djet cars that were kept running.. over heated their cylinder heads... and dropped valve seats with the gas changes. Thus the negative stories.

[JamesM]

WOT numbers sounds pretty good, especially if you are still holding in the 12s under load at 5900RPM

Are you running a stock cam? All my stock cam cars are done making power well before 5900.

When im tuning Megasquirted cars I usually have the AFR targets set mid 12s under load and mid-high 13s cruise, though i have suspected i could probably lean out the cruise area a bit more. I usually try to keep it out of the 14s unless in overrun but with the thin, hot, dry, air in salt lake I try to error a little on the rich side to help the head temps.

If your head temps are good I would say your numbers are fine.


Around here with my 2.0 d-jet cars (that do have temp monitoring) its not uncommon
for me to see 380-390 (depending on the day) at the #3 plug pushing it on the freeway.

My cam'd high compression 2056 Megasquirt car usually runs ~50 deg cooler

Absolutely not trying to be negative

I hope you have a cooler on those cars
Those are pretty high head temps. I typically run 300 max. But have seen 340+ a hair
(On the track worse)

I have a long standing theory. That the Djet cars that were kept running.. over heated their cylinder heads... and dropped valve seats with the gas changes. Thus the negative stories.

Na no cooler, they are bone stock. Around town driving they are fine and dont ever see over 350, they only get up into the pucker temps if im pushing them pretty hard for extended periods at higher speeds on hot days so I just try and drive mindfully. I dont like them being that high but every stock d-jet 2.0 i have ever had runs similar temps around here. Temps were better when i lived in California and usually stayed closer to the 325 range, I just think the Germans didnt design these things to be driven at a sustained 85+ MPH in 100+ degree weather at altitudes where you only have 85% of the cooling air density. its pretty much worst case scenario for air cooled sports cars around here. Haven't been able to blow one up yet though so I just keep pushing them as is. After having abused type 4s for 20 years I have come to the conclusion that well built/maintained ones are a lot more durable than people give them credit for.

These readings are all from VDO gauges though so who knows how accurate they actually are. In the process of swapping them out for Dakota Digital ones.

Was really happy to see the temps my built 2056 runs at, have read for a long time that the stock d-jet cam runs the heads hot but I was still surprised to see the difference though given how much more power the 2056 is putting out.


You may be right about the gas killing motors, or at least accelerating their death, it absolutely makes a difference at least from what I have seen. Nearest corner gas station to my house sells 88 Ethanol free so i almost always run that however its noticeable when I don't, especially if I drive further up in the mountains. Started having vapor locking problems a few years ago seemingly out of the blue and eventually figured out the gas I put in the car had a lot to do with it. Ethanol free, no problem. Standard pump gas though when i would get over about 10,000 ft elevation would almost always without fail start boiling the fuel in the lines. Wound up relocating the pumps so I could go on longer trips and not have to worry about finding good gas.