Aircooled

Will reverse flow cooling really help an LS1 run more compression without detonating on pump gas?
Usually this is just assumed to be true, but I’m starting to wonder if that is really the case.
It seems to be pretty well documented that if you run a 160 stat and reset your cooling fans accordingly, the cylinder head temp will hold a constant 160*. If this is true, then how is reverse cooling going to improve anything? There is a limit as to how cold you want to let an engine operate. Also, how many LS1’s are truly experiencing detonation from too much compression on pump gas? Are these engine holding a constant 160* head temp or not? Do the owners believe that reverse flow cooling would reduce their detonation? Everyone wants to run as much compression as possible, but are the headaches of reverse flow cooling (difficulty purging air from system, hot spots due to vapor bubble traps, etc.) really going to gain you anything?

Terry Burger

iTrader: (4)

It should but didn't turn out that way in my case.

LS1derfull

Reverse cooling would allow lean fuel curves and more aggressive timing, not just compression increases. I cant answer how much LS1 would gain but in theory it would allow for more power, also you do want coolant temp low but oil temp very hot.This is hard to do but engine dyno shows power gains when testing this way.The bigger the temperature differential between comb. chamber and coolant areas the less energy is lost on power stroke to the coolant system. I like the idea of hi pressure radiator cap to help keep air pockets from forming and to raise boiling point in system.

Patman

The theory behind reverse flow cooling is great, getting colder coolant to the heads to keep detonation at bay, and warmer coolant to the bottom end for reduced friction. However in reality, the system would end up with a lot of air pockets in it, so it didn't quite work out as well as GM had hoped.

jmX

[quote]Originally posted by Patman:
<strong>the system would end up with a lot of air pockets in it, so it didn't quite work out as well as GM had hoped.</strong><hr></blockquote>

Isnt that why we have the coolant vent tubes at the top of our heads? Seems like the air would work itself out just fine.

The Alchemist

iTrader: (19)

I think the best thing is to ask Mike M how he is making out with his reversed cooled electric water pump. Joe installed it on his car a week or so ago and there were no air pocket issues.
I beleive the air pocket issue was one of the first things ironed out during the R&D phase.


Hopefully Mike M will come in and respond.

JS

iTrader: (4)

Brien I think u misunderstood the post.I'm sure the pump is working well on Mike's car.

What we all want to know is how well is it working and how much benefit will we all see.JPR has NEVER done testing on the same day like Trry Burger has and he only picked up 5RWHP on a stout H/C car.I dont think Terry was too pleased by his post but never the less I'm sure Terry will continue to run it.

Now for the milder guys it might make even more HP and for sure the FI guys should really benefit but until JPR does actual SAME DAY testing on a FI motor or for that matter ANY motor NO ONE will spend 850 bucks on this Pet Rock.

JS

[ March 02, 2002: Message edited by: JS ]

[ March 02, 2002: Message edited by: JS ]</p>

Terry Burger

iTrader: (4)

Like I said, I run 11.3:1 cr. With my reverse flow EWP I pick up only 5-6rwhp from 5000+rpm. I am not able to run any more timing than I do now (~25 degrees). I think it can work for some setups, but it doesn't do much for my car.

The Alchemist

iTrader: (19)

Joel, if you look at the last posts that I was responding to, the question was if anyone was having problems with air pockets.

Its kind of funny how all of a sudden you've turned from I gotta have it to 'Joe's pet rock'

JS

iTrader: (4)

Terry at least u did your testing on the same day with a stock pump vs a EWP.Thats good information.I dont see it making more than 10RWHP on a FI motor but lets face facts.10RWHP is big when u r done modding and are looking for that litle extra.

I know how u feel though.I bought Dynatech STEPPED headers and thougth I'd get 10 and 10 but I LOST HP and TQ under 5500.Safe to say there getting sold to a stroker guy and I'm going back to my Macs.

JS

[ March 02, 2002: Message edited by: JS ]

[ March 02, 2002: Message edited by: JS ]</p>

JS

iTrader: (4)

I really wanted one Brien but until someone does REAL testing back to back on the same day no one will buy the pump.If it works u can bet I will have one but from the looks of it 5RWHP is what to expect.

I just got creamed on a set of DYNATECHS that were suppose to be the header to run.Instead they were too big and I lost HP.I'm not gona be someones lab rat again.

JS

[ March 02, 2002: Message edited by: JS ]

[ March 02, 2002: Message edited by: JS ]</p>

Aircooled

[quote]Originally posted by Terry Burger:
<strong>I am not able to run any more timing than I do now (~25 degrees). </strong><hr></blockquote>

So, you tried to run more timing, but encountered detonation? This looks like a good datapoint.

Aircooled

[quote]Originally posted by LS1derfull:
<strong>Reverse cooling would allow lean fuel curves and more aggressive timing, not just compression increases. .... in theory it would allow for more power.</strong><hr></blockquote>

This is what I'm questioning. I agree that, in theory, the cooler you keep the heads, the more aggressive you can get with fuel, timing and compression and thus the more power you can make. However, will adding reverse cooling to an LS1 convert this theory into reality?
How much cooler can the heads get w/ reverse flow? How much cooler do you want to let the heads get (bottom end reliability)? I keep coming up with 120*F as the lower limit. Assume that you have 1300*F (common EGT number, I think)combustion gases on one side of the head and either 160*F (forward flow) or 120*F (rev. flow) coolant on the other side. Reverse flow cooling would then only increase the cylinder head heat removal by 3.5% [(1300-120)-(1300-160)]/(1300-160). Is this really going to put more measureable power to the ground? I really don't know.

[quote]Originally posted by LS1derfull:
<strong> The bigger the temperature differential between comb. chamber and coolant areas the less energy is lost on power stroke to the coolant system. </strong><hr></blockquote>

Actually that's backwards. Larger temperature differentials cause more energy to be lost to the cooling system, thus making the engine less efficient. [Q=MCp(T1-T2) You just hope that the cooler heads allow you to make enough additional BMEP within your octane limit to net a power gain despite the efficiency loss.

Joe Prince

Posted by.... you guessed it ... JS.

"What we all want to know is how well is it working and how much benefit will we all see.JPR has NEVER done testing on the same day like Trry Burger has and he only picked up 5RWHP on a stout H/C car.I dont think Terry was too pleased by his post but never the less I'm sure Terry will continue to run it.

Now for the milder guys it might make even more HP and for sure the FI guys should really benefit but until JPR does actual SAME DAY testing on a FI motor or for that matter ANY motor NO ONE will spend 850 bucks on this Pet Rock.

JS"


Well it seems like you are out on a negative campaign against this product without any merit to back it up, you out of all people know first hand what this pump has been through in respect to testing and nothing that you have mentioned above has any factual based support. You should know better than this. I think a good place to start is to find out what temp the heads make the best power/how much heat gain is picked up during a quarter mile run both ways (forwards and reverse) and how stable the head temps are at high speeds both forwards and reverse, this has all been covered in the past. Granted.. I believe that FI / high compression / larger CI would be the most benifited with this particular Pat Pend applied reverse cooled system, I have a new housing that is a conventionally cooled housing (Pat Pend applied)to test back to back against the reverse cooled housing.

ONYXSS

JS, what in the world happened with those headers? I'm getting real confused. I just read on LS1 com that you guys might have mis-read the data, and that now you're keeping the dynatechs <img src="images/icons/confused.gif" border="0">

CHRISPY

Alright guys,
This has to calm down. You can't really compare Terry's pump to Joe P's pump and results. They both may be reverse cooled but there is a LOT of differences between the two designs.

JS stating:
"NO ONE will spend 850 bucks on this Pet Rock."

Is just flame bait. I am surprised you would post this after your relationship with Joe and how you praised the pump from the beginning.
I dont think their is an issue with the build quality or performance of the pump holding up release of the pump or dyno information.

There is a legal issue between JPR and another party concerning the pump which you are fully aware of.

Keep it civil and keep it clean please.
Peace,
Chris

[ March 05, 2002: Message edited by: Chris ARE 360 ]</p>

JS

iTrader: (4)

Chris it wasnt a flame.
If it was taken that way then I'm sorry.
Joe knows I believe in his stuff,I ran pretty well with it.All I meant was get some back to back testing done and lets see this thing shine like we know it can.He'll have guys waiting in line for it.

JS

mike m

iTrader: (6)

well the ewp is on my car. i will be doing back to back testing for Joe, i am waiting on a few things for my car then i will track test it with the ewp the i will switch back to the stock and see the difference. we will also do the same testing on the dyno. i myself am not even concerened with power gains. i care more about the fact that i will have less chance of detonation with my setup. im sure the power gains should be good even just from removing the 2 pulleys from the water pump.

JS

iTrader: (4)

Now u guys r thinking correctly.Dyno with it on and off on the same day.I bet u see good results Joe once u fine tune the car in.

Good luck
JS

Terry Burger

iTrader: (4)

[quote]You can't really compare Terry's pump to Joe P's pump and results. They both may be reverse cooled but there is a LOT of differences between the two designs. <hr></blockquote>

I agree with that. Joe's setup might work a lot better than mine. I just wanted to share my results with everyone. So far I haven't track testing mine. Maybe it will be worth .1th? I hope to find out Saturday.