shanghai_todd

iTrader: (2)

My LS2 conversion is about a week away from being completed and the million dollar question is will my rear mounted radiator setup work???

The concern is with the radiator being mounted above the engine and flat how to handle over flow and the vent tubes from the heads?

I have been looking at post about expansion tanks but have no idea how to incorporate into my setup.

Looking for comments and suggestions.

Here is what I have:
- custom made all aluminum radiator (fills from the top when lid is closed)
- 2 Spal fans controlled by PCM to come on at 180 and 185
- Renegade Hybrid adaptor blocks to bypass stock water pump
- External 55GPM water pump
- Custom Tstat housing with 180 degree Tstat
- 20AN Nascar flex hoses and threaded bungs

Here are some pictures

Mike00ss

iTrader: (9)

wow 71 views and no responds! bump to the top for a crazy set up, hope it works!

eastcoastbumps

iTrader: (1)

There is plenty of air flow over the lid and through the radiator with it mounted there so it should have good cooling. You shouldn't have any trouble bleeding it if your fill point is the highest point as well. An expansion tank will be easy to add. It doesn't matter how high it is. It doesn't have to be level with the radiator cap. The cap doesn't have to be the highest point either. It would be ideal, but as long as you can still bleed it from the highest point it will be ok. You could weld on a neck and cap as well as a nipple onto that aluminum tube. Run the steam vents to the nipple and you'll be set.

Nice looking swap! Have any more pics? Those 993's are wonderful cars.

Born-again 7

"custom made all aluminum radiator (fills from the top when lid is closed)"


I love the car. Have you thought of putting a fill cap where that 90 degree an fitting is on the top side of the radiator? That seems like the most logical.

shanghai_todd

iTrader: (2)

Thanks for the feedback, I has actually thinking of adding a bleeder valve to the crossover tube to help vent air out when filling from the top. In regards to the expansion tank I am still unsure how to plumb it. would I open the threaded fill point from the top and route it into the expansion tank? And then route the cross over tube into the expansion tank?

The complete build is posted in my Porsche community below.

http://forums.pelicanparts.com/porsc...ion-911-a.html

shanghai_todd

iTrader: (2)

Yes, in the last picture with the lid closed you can see I put a threaded cap in place of the 90 degree AN fitting. I actually have the electric water pump run and put a funnel into this opening and fill from the top. I then open the cross over tube to burp out any air. Seem to work wekk but not sure what will happen once coolant expands.

pdsq98gt

Use one of those vacuum style coolant fillers to make sure you don't have any air.

ma70tt

imo might want to close the areas around the radiator with sheet aluminum so the air passes through the radiator. airlift makes some decent cooalant vac equipment,

Tainted

iTrader: (9)

cool car

shanghai_todd

iTrader: (2)

Looks like this weekend was a bust. The front cover kit I ordered from GM Discount parts was missing the front cover.. Had the seals, bolts, sensor but missing the friggin cover.. What a pain in the ***!!

Guess I will have to wait another week.

Stu Cool

iTrader: (13)

I think it will work fine, these motors are not hard to cool unless you went silly with compression. You might even find that you do not need the second fan to come on that soon, But that is something you can experiment with once you are running. Good job so far!

Pat

shanghai_todd

iTrader: (2)

Its Alive!! and just in time for fathers day

I still have some some testing of the radiator to do but I was able to drive around the block and the coolant temps seems to stay steady at 198~199F while driving and in idle. Considering that the outside temps in Tampa today were 96F my first impressions are good.

What should the average coolant and oil temps I should be looking for?



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shanghai_todd

iTrader: (2)

http://www.youtube.com/watch?v=uEaCr7tsIis

http://www.youtube.com/watch?v=TF0D7JYB-ow

themachasy

iTrader: (5)

Holy crap that thing is awesome!!! MOARRRRR

motorsports601

In ls1 sandrails they mount radiators in all kinds of positions and they run in 120 degree weather at agressive throttle u might want to post this on glamisdunes.com under sandrail tech.. they have solved all kinds of cooling issues in ls1 engines from mild to wild.. what size is ur radiator size dimensions gallons single pass dual pass what size is the lines inside?, what cfms r ur fans? Is ur engine stock? I've heard theses engines have trouble getting all the air out of the cooling system. Very nice car awesome swap!

lazylongboarder

iTrader: (2)

LS motors in my experience are happiest around 195-200 with both the oil and water. I run 11 qts of german castrol 5w30 and 5 gal. distilled water/20% coolant. My temps were always around 205 before adding a ginormous Setrab oil cooler. Both the water AND oil are a nice-stable 185-190 no matter how hard I drive it. Direct airflow is key. I added a GT2 front splitter which made a dramatic difference in cooling. But my setup is in the front. I've got a BIG Ron Davis Rad and equal sized setrab oil cooler. It's taken a long time with lots of trial and error. I suggest shrouding around the Rad and put the biggest most powerful fans you can fit. That'll aid in getting exhaust heat out of the engine bay as well. Oil coolers help stabilize both oil AND water temps. I highly suggest fitting the largest one you can...even the stock front mount Porsche cooler with some custom adapters would work wonders.

If you find that you can't get enough air into the rad with the standard 993 turbo decklid, you can also look at the GT2 lid (wing/decklid/spoiler) with the side intakes engineered to get more airflow into that intercooler (which would be your rad). Also the Turbo S has side intakes that make it a slightly larger wing.
I'm interested in seeing how your cooling issues are resolved since I'm putting an intercooler in that same spot. It worked for Porsche A.G. because of the large cooling fan always drawing air through the IC and over the cylinders. BUT since we're water cooled now we don't have that vacuum drawing fresh air over our rad/IC's. I might end up having to move my IC's to the side wheel wells like the 996/997...

These keep popping up, more and more guys are seeing what a great super-car value these 911/LS swaps are. 2600 lbs, 400 rwhp, daily drivable with A/C, german handling...Pretty bad ***.
Keep up the momentum. This is looking great.

shanghai_todd

iTrader: (2)

Getting great feedback on the forums and plan to drain the current radiator fluid/ water mix to measure how much fluid my system holds. Also going to re-fill with distilled water and Dexcool and do a couple of different test. I did decide to add an adjustable thermostat to give me more control over the fan on temps, currently coming on around 180F. I hard wired it so that the fans continue to run when the car is turned off, only runs for a couple of minutes so no worries on killing the battery

First test: 20min idle time while sitting in the garage with no incoming air. Fan's pulling in air and pushing over the intake and engine. Temp range after heated up was 198~205F. Average coolant temp after warmed up stayed at 200F.

I think I will get better results by reversing the fans to take heat out of the engine compartment. The fans are defiantly pushing some air and I can feel plenty of heat being drawn thru the radiator.

Unfortunately I have business travel in Europe over the next 2 weeks so have to put the project on hold again until I get back.

lazylongboarder

iTrader: (2)

Hopefully you won't be depending on the fans to do the majority of the cooling. Air travels the easiest route, so a huge amount of air is going around the radiator, not through it. Shrouding around the rad will drastically lower fan usage. The only time the fans should kick on is with A/C low speed and around town, and when you're stopped.
Once you get going the primary concern should be getting every bit of that air through the rad, not around it. I had similar complications with my initial cooling setup. The brake ducts in the front bumper were receiving more air than the larger central rad intake...because it was easier for the air to go through the ducts than through the thick radiator. Once I directed the air up with a splitter and capping 1/2 of the brake ducts and forced the air into the rad my fans rarely kick on. Dramatic difference.

Russ

1dirtyZ

iTrader: (1)

i love what you are doing here and great information !

got a couple of questions for you :

if there is space , why not run two oil coolers ( like mentioned before : biggest you can fit ) in the area behind the rear wheels ? i belive that is where the original mufflers used to be . you can always add some fans to the if airflow was an issue .

the other question is what is the air flow like on top of the deck lid at hiway speeds on these cars? is it a positive pressure area where air will move from outside to inside the engine compartment ? or is it a negative pressure area where the engine compartment gets pressurized and and air is either sucked out or pushed out of the compartment into the atmosphere above the lid?

the reason i ask is cause you don't want the fans to be working opposite of the natural flow of air ( trust me i know ,,,, i took me a while to figure out why my scout would overheat at 40 mph only )


and definatly make sure you shroud the radiator properly like lazylongboarder said , it makes a huge difference.

another small trick ( or band aid fix depending on how you look at it) is to route one of the winshield washer nozzles to the radiator and have it spray on it for when ever you need a quick cool down .

lazylongboarder

iTrader: (2)

Well put.

I've been wondering the same thing. If it isn't gonna be sufficient airflow to keep my IAT's down I'll lose the wing and go with A2W. I'm jealous of your side IC intakes dirty. That's gonna be retarded when you jump into F/I

Back on subject. Basically it would be difficult to put too large of coolers in these cars. So leave the front mount rad/oil cooler an option if trial and error doesn't work with the rear mount. I believe Toy-Jet played around with a few different wing designs.
I'm using the same Meziere Water pump with my front mount and it works like a champ for cam/heads N/A. I haven't fired my F/I motor up with it yet, I may be adding a second in line pump and 2 additional secondary smaller rads if I can't keep the temps under control in the mile.
It's trial and error man!!! Keep us updated after the trip.