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I think that has more to do with the heater core performance. The rear cross over doesn't go anywhere, other than to the heater core.
The thermostat is the device that restricts coolant for emissions and a hotter running car. The limiting factor for cooling system performance for typical C4's are:
1. Lack of cooling system maintenance
2. radiator size and access to air flow
3. Everything/anything else.
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Last edited by Tom400CFI; Mar 27, 2020 at 11:50 AM.
The rear passages are blocked off on a SBC. The only thing the rear passages do on an L98 for the vette is allow steam to be bled off through the small hose on the passanger side by the distributer. The L98 in the Camaro do not have this.
WHOOPS! You're right! I thought the heater core hose came from there....but you're right that it's just a small steam hose. That ain't gonna help cooling.
The rear passages are blocked off on a SBC. The only thing the rear passages do on an L98 for the vette is allow steam to be bled off through the small hose on the passanger side by the distributer. The L98 in the Camaro do not have this.
If you have a hard water problem where you live, then run distilled. The water you want to avoid is deionized. Deionized water will cause corrosion in the cooling system.
sstonebreaker is right that straight water will cool better than a typical water/coolant mix. IDK how the heat exchange rate of water compares w/Evans, however.
EDIT: It appears that water has better heat transfer characteristics than Evans. From their site: "Water has superior heat transfer capabilities but...."
EDIT II: Also found this on their web site:
"Does Evans lower the temperature?
I have a 1990 Jaguar V 12 XJS. I have had everything done to it but it still runs hot. I was looking at Evans Coolant. Is this a good fit?
David:
Typically this application will run the same temperature or slightly hotter as 50/50 antifreeze........ "
....so I'm not sure how recommending Evans "for a cooler running L98" is a good or accurate recommendation. (?)
Originally Posted by TommyFox
Well that was helpful lol.
The pic shows that there is no water passage across the rear.
WRT drilling the head and running hoses forward to the stat housing, by doing that, you're taking some of the coolant and passing the cylinder heads with it. I'm not sure that is the right idea.
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Last edited by Tom400CFI; Mar 27, 2020 at 03:51 PM.
I can't speak for the 84-86 iron headed cars. But 87+ L98 intake is not blocked off and neither is the head, hence the block off plate by the factory for emissions. I was told about this tip by a GM engineer many years ago.Tested it myself. No it's not a miracle and meant to be used by someone as a band aid who has never maintained their cooling system and has a gunked up radiator. I think I got a 3 or 4* drop in a summer climate. This works well in conjunction with other mods-you know the drill.
Rear flows ALL THE WAY through on the TPI intake
On the crossfire the rear is the feed or return (I forget) for the heater. But the entire underside of the intake is a crossover so having the rear ports open won't help mu h if any. The renegade just uses a crossover in the rear so having it open is ideal. More flow is more flow... it'll help a little I suppose but I never really saw a difference on mine.
87+ L98 intake is not blocked off and neither is the head, hence the block off plate by the factory for emissions.
Dude, we covered this earlier: the "emissions" is handled by the thermostat...not gaskets.
Originally Posted by TommyFox
I was told about this tip by a GM engineer many years ago.Tested it myself. No it's not a miracle and meant to be used by someone as a band aid who has never maintained their cooling system and has a gunked up radiator. I think I got a 3 or 4* drop in a summer climate. This works well in conjunction with other mods-you know the drill.
Rear flows ALL THE WAY through on the TPI intake
TO WHERE?? Tell us WHERE that crossover passage "flows to"?
I think that your GM engineering buddy was mistaken. Tell us how by-passing coolant past the cylinder head is going to help cooling, please....
Last edited by Tom400CFI; Mar 27, 2020 at 04:08 PM.
I can't speak for the 84-86 iron headed cars. But 87+ L98 intake is not blocked off and neither is the head, hence the block off plate by the factory for emissions. I was told about this tip by a GM engineer many years ago.Tested it myself. No it's not a miracle and meant to be used by someone as a band aid who has never maintained their cooling system and has a gunked up radiator. I think I got a 3 or 4* drop in a summer climate. This works well in conjunction with other mods-you know the drill.
Rear flows ALL THE WAY through on the TPI intake
Tommy, the intake is blocked off except for a very small hose on the passanger side that allows steam to be vented in the corvette since the manifold is higher then the radiator and GM did not want a steam pocket to develop in the head which would lead to detonation. What you are looking at is the the passanger side of the intake where the steam port is located. The drivers side is blocked off, there is no crossflow. The cylinder heads are symetrical so you can use them on either side of the engine, that is why there is a port at the back. If you study the flow you will see that there is no flow from the rear ports. Hope this helps.
Last edited by bjankuski; Mar 27, 2020 at 04:29 PM.
Tommy, the intake is blocked off except for a very small hose on the passanger side that allows steam to be vented in the corvette since the manifold is higher then the radiator and GM did not want a steam pocket to develop in the head which would lead to detonation. What you are looking at is the the passanger side of the intake where the steam port is located. The drivers side is blocked off, there is no crossflow. The cylinder heads are symetrical so you can use them on either side of the engine, that is why there is a port at the back. If you study the flow you will see that there is no flow from the rear ports. Hope this helps.
The actual intake is blocked off or the intake is blocked off by the head not open?
Tip for a cooler running L98
Thanks for the correction! 
