Odd thing, after the waterpump swap, and a switch to a 180 Thermostat (had a 160 in there) the RS feels like it gained 10 hp.

Would advanced timing be helped or hurt by a higher operating temperature?

I've been running a 160 stat, and 12 deg advanced timing for a long time now, went with the 180 stat and boom, power..

I don't count the water pump as the HP factor, mostly cause the old one spun with less drag than the new one.

Ideas?

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Shane McConnell
macgyver@nethirdgen.org [*]Webmaster of www.NEThirdgen.org[*]1991 RS 305 T5 15.6@88[*]1979 Z28 ZZ4/2004R (In the future.)
I'm the kinda guy you bring home to Mother.

 

If you T-stat was weak and not holding 160, and you were running too cold, then yes, you could have been loosing power.

 

160 stats also dont deliver very consistent performance when your car runs at that temp

 

Well, there you have it kids, 180 stat beats a 160, the car is running better now than it ever has.

 

If I'm not mistaken, the ECM will allow more total advance when the engine is warmer, because it is safer to rev higher when the oil is warmed up and circulating.

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Working on:
'84 Z28 LG4 305
Added dual elec fans.
145 MPH IROC Speedo
Building 430 HP 350
using primarily GMPP parts.
Block is in shop!

Awaiting results from all 8 ASE tests.

Starting to look like the Kicker poster child!

 

btw mac thats why i switched to a 180 aswell (did so a few days ago) from my own testing and the advice of some gurus, i found cooler temps were way inconsistent for performance

i dont think there is that much of a timing issue (i dont know about the 746 whether it has a wot advance vs coolant table) but there is a substantial difference in fueling from 160 to 180, not to mention, oil temps are generally closer to optimal, as a cooler oil takes more hp to circulate but you dont want it hot enough to where the protection is compromised

i had previously bought into the notion that cooler was better but thats not true when it comes to T stats

 

Yes, but your cars are TBI (I suspect Shane's is too) and I would agree that TBI cars need some heat in the manifold as you have a wet intake. So a 180 is probably optimal for it. I know when I had carbed vehicles, 180s gave the best performance for me.

On my TPI car, the 160 gives VERY consistent performance. In fact, with higher temperatures, it becomes SLOW...due to the wonderful heat-sink of a TPI intake.

Of course when the ambient air temperature is cooler, it is a little quicker, but that has more to do with the cooler denser air charge. So I will continue to use a 160 on my TPI car as I have a dry intake.

 

When I put 160* on my TPI, it made it noticeably slower. Put the stock 195* in there and got my power back.

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'92 Formula
305 TPI 5speed
1LE package
Mods: SLP headers,SLP catback,SLP air foil,ported plenum,Crane AFPR (47psi),MSD6AL,AC delco cold plugs, Bosch O2sensor, homemade cold air,K&Ns,3:73s,JET fan switch, Macewen white face gauges

 

I noticed a big power gain when I put a 160* in my car.

 

On the timing v. temp... for each 25ºF reduction in inlet temp you can increase timing by 2º.

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"The people always have some champion whom they set over them and nurse into greatness... This and no other is the root from which a tyrant springs; when he first appears he is a protector.
-Plato

 

Hey Mac, isn't 12* advance kinda a lot for a TBI engine? Stock there 0*



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Eric Natzke
91 Firebird 305 TBI (ZZ5 summer of "01")
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http://members.aol.com/j007golden/91firebird.html
For info on certain parts or mods go to the site below
http://members.aol.com/j007golden/modeval.html

 

12* is kinda alot, but hey, the motor runs well with that timing, I HAVE to run 93+ octane though...