# Running Hot On The Hwy : Timing Questions (Megasquirt)



## Shawn B (Nov 27, 2003)

My car has been running really good this year but starts to get hot out on the highway. As I go faster the hotter the coolant temps get. AFR's look good to me (all in the 14's with the occasional blip to 13.9 ish or 15.1 ish, average AFR from the recent datalog on the hwy shows 14.2 as the average) but I am wondering if maybe my timing is too advanced above 3000 rpm. At 3500 rpm timing is around 23 degrees and around 4000 rpm timing goes to 26 degrees, with the highaest spark angle seen being 29. Cruising at these rpms is all done in the 50 - 60 kpa range on my table.
I hope this makes sense and any help is always appreciated. Thanks in advance.


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## broko (Mar 18, 2005)

well, your spark map looks very conservative. 
here's what mine looks like. took it from vcg's 1.8 turbo map.


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## Salsa GTI (Aug 29, 2000)

*Re: Running Hot On The Hwy : Timing Questions (Shawn B)*

turbo car or na...
to the OP


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## Shawn B (Nov 27, 2003)

*Re: (broko)*


_Quote, originally posted by *broko* »_well, your spark map looks very conservative. 
here's what mine looks like. took it from vcg's 1.8 turbo map. 


I'm familiar with that ignition table as I've run it before.
Maybe I need a little more fuel at those highway cruising speeds?


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## Shawn B (Nov 27, 2003)

*Re: Running Hot On The Hwy : Timing Questions (Salsa GTI)*


_Quote, originally posted by *Salsa GTI* »_turbo car or na...
to the OP

Turbo 2.0L 8V


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## Salsa GTI (Aug 29, 2000)

*Re: Running Hot On The Hwy : Timing Questions (Shawn B)*

i would actualy try more timing in the high vac area.
Is your water pump ok?
Are you running a t stat?
ive seen many cars run hot without a t stat..
i thing its a cooling system issue more than a tuning issue


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## need_a_VR6 (May 19, 1999)

*Re: Running Hot On The Hwy : Timing Questions (Salsa GTI)*

I run 45deg timing at highway cruise with no issues, and can run as lean as 16:1 without a hiccup. 
It's a cooling issue for sure..


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## ValveCoverGasket (Mar 20, 2002)

*Re: Running Hot On The Hwy : Timing Questions (need_a_VR6)*


_Quote, originally posted by *need_a_VR6* »_
It's a cooling issue for sure.. 

indeed...
that map actually looks really conservative, and as mentioned, you can run a lot leaner as well if youd like during cruise


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## Prof315 (Jan 5, 2009)

*Re: Running Hot On The Hwy : Timing Questions (ValveCoverGasket)*


_Quote, originally posted by *ValveCoverGasket* »_
indeed...


x3 http://****************.com/smile/emthup.gif sounds very much like a partially blocked radiator


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## Shawn B (Nov 27, 2003)

*Re: Running Hot On The Hwy : Timing Questions (Prof315)*

Thanks guys!
Water pump is good and the thermostat is new (tested).
The rad does have the intercooler in front of it.
Let's go over this again, how hot is too hot?


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## B4S (Apr 16, 2003)

*FV-QR*

I cruise at 95*C.


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (B4S)*

my rabbit runs at about 180 and my gti runs about 190
neither ever get warmer unless sitting in traffic, and they go up maybe 5-10deg tops


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (-RalleyTuned-)*

Down the highway at 120 kmph I see water temps around 200 F - 210 F. Around town and sitting in traffic doesn't worry me at 186 F. Are my temps normal then?


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## broko (Mar 18, 2005)

highway is at 180-190 for me, city driving is around 200 on 100+deg weather and a rabbit rad.


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Shawn B)*

210 on the hwy seems pretty hot, i wouldn't say overheating but definetly on the hot side...
what radiator do you have? maybe try to run the large mk2 one?


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## Southcross (Jul 2, 2004)

*FV-QR*

I'm wondering... where are people putting their coolant temp sensors? You can obtain different temp values just altering where your sensor is located.
i.e. side of head, coolant flange main flow, recirc hose (head back to pump), heater hose, radiator hose


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Southcross)*

i always use the side of the head, easiest way and it threads right in







(if you use the saturn sensor)


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## Southcross (Jul 2, 2004)

*FV-QR*


_Quote, originally posted by *-RalleyTuned-* »_(if you use the saturn sensor)

The Saturn sensor is "GM" (Ohm range) compatible? and 10x1 threaded? :shock:


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Southcross)*

yup, screws right in to the small hole on the front most side in the head. used it on 4 cars now and it's never failed or leaked. i use em in everything now, much easier than finding adaptors and crap


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (-RalleyTuned-)*


_Quote, originally posted by *-RalleyTuned-* »_210 on the hwy seems pretty hot, i wouldn't say overheating but definetly on the hot side...
what radiator do you have? maybe try to run the large mk2 one?

Using a non-overflow rad but using the overflow from the ABA head. It is the biggest rad I can fit in there. I haven't really seen temps as high as 210 but more like 201 ish (just said 210 to identify it was over 200).


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Shawn B)*

that isnt really out of line...but seems odd you get hotter temps in town than running down the freeway...
what coolant sensor are you using?


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## Southcross (Jul 2, 2004)

*FV-QR*


_Quote, originally posted by *-RalleyTuned-* »_yup, screws right in to the small hole on the front most side in the head. used it on 4 cars now and it's never failed or leaked. i use em in everything now, much easier than finding adaptors and crap


****... I had to pay a guy to tig-weld on a 3/8" NPT bung for the GM sensor


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Southcross)*

there is alot of mis-information out there for those sensors...been using them for over a year now in several installs with no problems


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (-RalleyTuned-)*


_Quote, originally posted by *-RalleyTuned-* »_that isnt really out of line...but seems odd you get hotter temps in town than running down the freeway...
what coolant sensor are you using?

No,hotter temps on the highway than around town. Just around town and anything under 80 - 100 km ph is fine and doesn' worry me from 177 - 186 degrees, even 191 doesn't bother me. But out on the highway above 100km ph the temp goes up. GM coolant temp sensor and maybe a little higher than my mechanical gauge but pretty close.


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Shawn B)*

that's what i meant haha
where is it located at? does it raise and keep getting warmer or does it maintain that temp while cruising?


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (-RalleyTuned-)*

Stays constant as far as I know. The coolant temp sensor is in a custom bung in the water neck on the side of the head. The mechanical gauge temp sender is in a bung from diggatrom/wraith also in the water outlet on the side of the head.


_Modified by Shawn B at 7:26 PM 7-2-2009_


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## mjleamy (Mar 16, 2004)

*Re: FV-QR (-RalleyTuned-)*

Is this one of the Saturn sensors that screws in? 
http://www.thepartsbin.com/cat...+6916


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## Southcross (Jul 2, 2004)

*FV-QR*

I chose to install mine in the radiator coolant neck... you always get true "coolant inside the engine" temp (on its way to the radiator). I want to capture temps from the pre-heat recycle as well as the main coolant flow, I also have a heater delete and a temp sensor in the side of the head may be fooled by the temp of the head itself.


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## Southcross (Jul 2, 2004)

*FV-QR*

oh hey! I just remembered something about MegaSquirt coolant temp sensors... is it a Delphi "GM" coolant sensor? Model # 12146312 sold by DIYautotune.com? if so, while "compatible" with the stock GM sensor, according to their product data sheet it has a slightly different resistance curve when it approaches the boiling point.


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (Southcross)*

What sensor is that? I am using the regular GM CLT sensor?
So if my coolant temps aren't too far off from what you guys posted, maybe I'll look into an oil cooler and a way to lower my intake temps (water/meth injection).


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Shawn B)*

those are just bandaids for poor cooling...is your intercooler blocking your whole radiator? id see if removing the intercooler from in front brings your freeway temps back into normal (not the oil cooler, but you wont see lower coolant temps with the oil cooler, just lower oil temps)


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (-RalleyTuned-)*


_Quote, originally posted by *-RalleyTuned-* »_...is your intercooler blocking your whole radiator? 

Pretty much.
Move it eh? 
Sounds good but pretty sure I'd need a new intercooler if I wanted to "move" it.


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Shawn B)*

maybe one day pop your intercooler off and go for a cruise down the freeway. the tune should be ok for driving off boost, so you shouldn't hurt anything. that will let you know for sure if that is what is causing the hot condition on the freeway


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (-RalleyTuned-)*

Starting looking at other intercooler options earlier today so I can move it from in front of the rad.


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## Southcross (Jul 2, 2004)

*FV-QR*

as long as air flows through the intercooler, it shouldn't cause cooling issues. People usually have intercooler caused cooling issues when they drive slower speeds (not as much air flow through the IC)


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (Southcross)*

Tried to fit a G60 IC side mounted down low .......... no dice. Just gunna run with this setup for now, still weird that I get hot out on the hwy but cruising around town is good.


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## -RalleyTuned- (Nov 17, 2008)

*Re: FV-QR (Shawn B)*

guess you could always put your window squirters in fornt of the rad to spray water on it if it gets too hot









but really those temps aren't much to worry about, over 210-215 is a bit too warm though


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## Shawn B (Nov 27, 2003)

*Re: FV-QR (-RalleyTuned-)*


_Quote, originally posted by *-RalleyTuned-* »_guess you could always put your window squirters in fornt of the rad to spray water on it if it gets too hot









You laugh but I had my washer squirters setup to spray straight winter washer fluid on the IC with my old G60 setup http://****************.com/smile/emthup.gif


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## Southcross (Jul 2, 2004)

*FV-QR*


_Quote, originally posted by *Shawn B* »_
You laugh but I had my washer squirters setup to spray straight winter washer fluid on the IC with my old G60 setup http://****************.com/smile/emthup.gif


I bought a pesticide/herbicide sprayer from Harbor Freight to do the same thing between runs when I'm at the track... best $9 evar!


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