Hey V8 conversion 914ers,

I’ve been running my car for some 7 years now and chose to exhaust the radiator out the bottom of the car. It seemed to work fine, but in the 100 degree summer heat of Willow Springs, I was seeing water hitting 250 degrees with fans blazing.

We all know that from the 60’s, race cars have vented out to TOP of the hood and it worked well for a friend’s Corvair 327 Chevy we ran at Riverside (142 MPH on the short course back straight). However, I originally didn’t want the car to look too “radical.” When I got the car running it had 11” fender flairs, side scoops, roof scoop and a wing……Ya’ cops won’t notice my car!

With some time before my next event, I redid the whole radiator layout where I sealed the bottom of the trunk, HACKED a hole in the hood and fabricated radiator shrouding and an exhaust air dam. I upgraded my fans too.

This morning in 60 degree temps, I took the car for a drive AROUND town at low speeds to see if I could keep it from overheating in traffic, as it used to. What I found surprised me: I drove the whole run with NO fans and water temp at 140 degrees. When I was caught by a stop light, the temp went up to 160, but once moving again, it moved back down.

I jumped on the freeway and both oil and water dove down to 120 again. EUREKA, I have found my solution!

Conclusion:
-Of course 120 is lower than desired, in spite of the 180 degree T-stat, but I’m aiming at the right temp ON-Track in Summer. If I want to so some street driving, I can always tape off some of my intake opening.

-In the previous configuration, I would have had to run the radiator + oil cooler fans and worry about over heating, now with NO fans, the temps are on the low side.

-Before, the oil temp would exceed the water temp by some 30 degrees, now the oil matched the water temps, at least in street driving.

-The internal hood bracing defines the hole shape as a trapezoid, so I cut all the width I could get right to left. The back edge is defined by the rear wall of the trunk and from there I measured 12” forward, held my breath, and cut.

-If your V8 car is on the edge of overheating and big fans aren’t enough, give this a try. Mine is a pure “racer” design, but our friend byndbad914 came up with an attractive louvered approach that keeps his 500 HP small-block cool. In another design, AndyS created a very attractive molded “air dam” for his LS1 conversion.

Being pleased to see all the work was worth it, I wanted to pass it along.

Best,
Terry

What radiator is this in your car?
I am considering cutting the hood for more air as well. Good to see it works well.

[quote name='kyracedog' date='May 1 2010, 05:44 PM' post='1312252']
What radiator is this in your car?
I am considering cutting the hood for more air as well. Good to see it works well.



[quote name='stewteral' post='1308505' date='Apr 24 2010, 09:00 AM']
Hey V8 conversion 914ers,

I’ve been running my car for some 7 years now and chose to exhaust the radiator out the bottom of the car. It seemed to work fine, but in the 100 degree summer heat of Willow Springs, I was seeing water hitting 250 degrees with fans blazing.

We all know that from the 60’s, race cars have vented out to TOP of the hood and it worked well for a friend’s Corvair 327 Chevy we ran at Riverside (142 MPH on the short course back straight). However, I originally didn’t want the car to look too “radical.” When I got the car running it had 11” fender flairs, side scoops, roof scoop and a wing……Ya’ cops won’t notice my car!

With some time before my next event, I redid the whole radiator layout where I sealed the bottom of the trunk, HACKED a hole in the hood and fabricated radiator shrouding and an exhaust air dam. I upgraded my fans too.

This morning in 60 degree temps, I took the car for a drive AROUND town at low speeds to see if I could keep it from overheating in traffic, as it used to. What I found surprised me: I drove the whole run with NO fans and water temp at 140 degrees. When I was caught by a stop light, the temp went up to 160, but once moving again, it moved back down.

I jumped on the freeway and both oil and water dove down to 120 again. EUREKA, I have found my solution!

Conclusion:
-Of course 120 is lower than desired, in spite of the 180 degree T-stat, but I’m aiming at the right temp ON-Track in Summer. If I want to so some street driving, I can always tape off some of my intake opening.

-In the previous configuration, I would have had to run the radiator + oil cooler fans and worry about over heating, now with NO fans, the temps are on the low side.

-Before, the oil temp would exceed the water temp by some 30 degrees, now the oil matched the water temps, at least in street driving.

-The internal hood bracing defines the hole shape as a trapezoid, so I cut all the width I could get right to left. The back edge is defined by the rear wall of the trunk and from there I measured 12” forward, held my breath, and cut.

-If your V8 car is on the edge of overheating and big fans aren’t enough, give this a try. Mine is a pure “racer” design, but our friend byndbad914 came up with an attractive louvered approach that keeps his 500 HP small-block cool. In another design, AndyS created a very attractive molded “air dam” for his LS1 conversion.

Being pleased to see all the work was worth it, I wanted to pass it along.

Best,
Terry


Hey kyracedog,

If you live anywhere that gets hot, I think it is the only way to go. Our bud, byndbad914, with the tube-frame V8 car, has a very attractive louvered exhaust that is hardly noticeable. You can check out his approach on his website: http://www.negativereinforcementracing.com/ . The outlet louvers are standard pieces from Summit Racing and readily available. byndad914 has a race-prep 355 SBC that puts out 500 HP at an insane RPM....he's a real engine builder.

Speaking of Summit Racing, that's where I got my radiator. It is a lower-cost ($270 current price) unit for a Camaro and measures 30-5/8" X 18-1/2". The Summit Racing number is SUM-380455. You can also chase eBay for a better price. I've run the stock radiator for 7+ years and simply put a high-pressure cap on it while relying on my header tank in the engine bay to purge the air from the system. The cap arrangement began to weep a bit, so just welded the filler neck over with a bleed hole for the initial fill up.

I liked the radiator because it was the BIGGEST I could fit in the car. To get it in between the headlight boxes took a bit of "massaging" of the boxes with a big hammer and in it went. Since I'm running a BUILT 383 SBC with 500+HP, I wanted the biggest I could get!

I'm a firm believer that there is no such thing as TOO much cooling and my new layout IS actually running the engine too cold (120 Deg.) However, as I said, I can easily block off parts of the intake to bring the temp up, if necessary.

My very smart bud AndyS advised me that the exhaust opening MUST be at least 1.7 times the intake area to ensure good pressure differential for good cooling. Carroll Smith advises that the INTAKE opening must be >40% of the radiator area, so I'll leave you to do all the calculating! The bottom line is that it works GREAT!

Good luck,
Terry

I'm curious about how much the engine lid needs to be vented to help cool the engine and to keep from cooking wires and hoses near the exhaust.
If the air intake is connected to ramair ducts in the quarter panels the lid isn't needed for combustion air but can the lid be closed off to help keep heat out of the cabin? Would that cause excessive temps in the engine compartment?

Click to view attachmentClick to view attachment

Hey Racer Chris:

All good questions. It is apparent that you also know that 30% of cooling of the Chevy is AIR FLOW over the block. I attached some photos to show what I've done:
-ENGINE COVER: I removed the entire stock cover, shined it up and put it in my living room as Porsche Art. Then I made my own "cover" from aluminum tube for the frame and ALL open screen. This also allowed me to raise it a bit for better aircleaner clearance. With 500 HP, I make a lot of heat, but have got it to work by running the ignition wires UNDER the headers, along with insulation tubing.
-All the water hoses are FORWARD to the high header heat and last for many years.
-With the cooling airflow for the V8 coming from under the car and flowing up & out the engine cover, I am a FIRM believer in OPENING up that airflow, rather than trying to close it off to reduce any heat getting into the passenger compartment. If that engine bay were closed off, it would be a HOT BOX!
-I'm resolved to the fact that inside the car is always WARM. Not only heat from the firewall, but I have the radiator water flowing in copper tubing in the shift tunnel! My solution that has worked great is the ROOF SCOOP I made with a sliding air control.
-Valve Cover View: Forget the Porsche Logo, that's just to confuse cops as most weren't BORN when the car was built. The photo is to show how the engine sits in the bay. The firewall is on the left and completely sealed.
-3rd Photo: This is to show the 180-degree exhaust system that I am running which required cutting out most of the trunk. I've taken advantage of the extra open area through the trunk by jacking the rear of the trunk lid by 1" (not even noticeable) to create a 56" wide exhaust vent.

In the 3rd photo, you can see the engine cross bar I built to hold the Chevy.
Since the photo, I've added a flexible air damn sticking down 3" to push more air up through the engine bay.

Also, at the bottom of the 3rd photo, you can see the stack of 2 oil coolers (each with a fan) next to the side scoops I made: Left side for oil coolers, Right side for fresh air to the air cleaner. I used to have a "ramair" tube & aircleaner set up, but
it didn't fit with the 180-degree headers. Now I have vanes channeling the air to the aircleaner and cannot tell any difference while the car has gotten faster.

I hope I've answered your questions, good luck with your car,
Terry

Thanks for those details Terry.
We have a LS-6 powered 914 at the shop right now and one of the problems is melted plastic items in the engine compartment. This seems to have become a serious problem since the engine lid was sealed off, which was done because the owner thought it would help keep heat out of the cockpit when he drives with the roof off.
I told him that opening the engine lid is necessary and a good way to provide interior cooling must be arranged. I'm interested in your roof scoop but with the radiator outlet in the front deck lid I would think the scoop might draw in hot air from the radiator.

Hey Racer Chris,

The quickest, easiest way to prove the benefits of "opening up the engine cover" would be simply loosening the 2 ten-millimeter bolts and REMOVE the cover.
The difference should be dramatic. I'd be interested to know the drop in the water temps.

I've heard a lot of concern about only getting hot air through my roof scoop, but have found that the radiator exhaust temps are not much higher than ambient.
Even though I'm dumping a lot of heat, the transfer occurs via such a large volume of air, that by the time it gets to the scoop, it still can cool me down.

If one is still not convinced, using 2 small scoops over the driver & passenger would move them outboard of the center radiator exhaust.

Good luck with your customer,
Terry

I think he commented that normal water temps were around 190 and during his most recent trip, since closing off the deck lid, they were 210 - still not problematic, but this was in 70 degree weather.
The engine needs some valvetrain reliability work before any real driving tests are conducted. It has some major mods that apparently aren't working well together. A local muscle car shop with a lot of LS1, LS6 tuning experience is helping us with that stuff.
I guess we'll see what we can come up with in regard to a fresh air duct over the top of the windshield frame.
Thanks for all your good advice,
Chris

Hey Chris,

As I expected, the "customer" car is running VERY high temps. Even with my "vent out the bottom" approach and mediocre fans, I could keep the car at 200 degrees or less on the street. The only problem was 100+ degree temps at Willow Springs in summer in the upper desert.

I'm surprised about the "valve train" reliability issue with the LSx engine as I'm running the reliable OLD flat-tappet cam & lifters in my SBC! I'd like to know what that issue is, as I had thought GM had finally built the "bullet proof" solution!

At the end of the day, with all that you are learning, I see you snatching Victory from the Jaws of Defete in CURING the high temps and being the HERO!! Can you Stand it?

Best of luck,
Terry

This engine has lots of cool parts like LS7 roller lifters, Trick Flow heads, Yella Terra rockers, and more. Enough to create 550hp FWHP!
It has suffered from lots of broken rockers though. The current hypothesis is that the (Comp) camshaft is simply wrong for the rest of the combination.

I'll be sure to share some of the glory with my mechanic. He's the one with the magic touch, lol.

.
"If you live anywhere that gets hot, I think it is the only way to go. Our bud, byndbad914, with the tube-frame V8 car, has a very attractive louvered exhaust that is hardly noticeable. You can check out his approach on his website: http://www.negativereinforcementracing.com/ . The outlet louvers are standard pieces from Summit Racing and readily available. byndad914 has a race-prep 355 SBC that puts out 500 HP at an insane RPM....he's a real engine builder."

ok so maybe i'm blind i looked all over the summit racing site for functional hood louvers and no joy. can you point out exactly where i might find some like the ones on byndad914's car? that is exactly the thing i have been searching for. i like the big hole in the hood look(as long as it has the proper ducting to go along with it) but i think the louvers are more my speed

Chris, if he is running Trick FLow heads, the pushrods are too long. They need to be shortened to solve the problem. Another LS6 owner here had that problem back at the Rocket City Ramble.

Same car, new owner.
I imagine the pushrods were changed, and other changes have been made too, but there are still problems. No broken rockers for now, but we had to replace a broken stud and helicoil the head where the other one on the same cylinder pulled out (& replaced that stud too).
The Corvette shop owner already looked at the ECU map and showed me that the ignition advance is way too much - over a wide operating range, and he said the AFR is way too lean as well. That's another source of excess heat in the engine compartment I'm sure.
...and there's more...
We'll get it sorted out so the new owner can have some fun for a change.

Roger that. Good luck with it. as for the tune, not necessarily. I tend to tune street cars really lean and with a lot of timing in areas of the map that the car just cruises or coasts. I would have to see the map before I made some judgement on that. When the timing is high and the AFRs are lean, there will be no excess heat generated. Usually it is when the timing is retarded and the mixture continues to burn in the exhaust, thus creating more heat.

Beyond 14.7 with an NA motor, there is less energy in the chamber, so running the car at 16-17:1 (if it will run that way) is really not a problem. You should use extra timing to get the lean mixture to light off reliably.

I have the Genesis louvers - I can't recall if I got them from HRP specifically but I think that was the case. It wasn't Summit tho'. I think some circle track places had 'em but not as cheap as I ended up finding. Have smaller ones in my roof as well.

Nonetheless, here is a link and you can search away on the net to find if there is better pricing elsewhere

http://www.hrpworld.com/index.cfm?form_pro...;action=product

Sounds like Bill's old car 'cept he would have made the power at the rear wheels Only way to have those problems are to either bind something (make sure that the retainers aren't bottoming on the seals - I have seen that overlooked more than a few times - and check all the normal bind stuff but I am guessing it is geometry as well.

Sometimes is just can't be fixed without stud relocation (if the stud is just in the wrong location - I have seen that too on some SBC heads that were imported thru Australia from China for awhile until I welded up a core, redid the stud location and sent it back to them to fix their design). I am not familiar with TF heads, been 10 yrs now since in the industry to that level, but if you have to rob Peter to pay Paul, you would rather have the rocker tip sit centered on the valve from mid to full lift, maybe roll jjuuuuussst a bit forward of center during that sweep, and let it roll off to the rear at the low lift since the spring force is low there.

Wrote a magazine article in the late 90s on how to do geom checks and so forth but no longer have a copy or I would scan it in.

This is Bill's old car. I have a dyno sheet that shows 460hp at the rear wheels at 6000rpm. The local expert says the power should keep going to 7000, but it's all done by 6500 with the current setup.
Oil consumption has been very high which would correlate to the seals being wiped out by the valve spring retainers.
The next step is to actually measure lift at the valves.

Aircraft engines run lean of peak quite a bit during cruise.
I think this was just set up a little too lean in an effort to make power.
I'm going to find out just how good these local guys are with SBC tuning pretty soon.
Last week I saw a Testarossa behind their shop that's getting a later model 512 engine upgrade with custom turbo installation.

thank you very much thats exactly what i have been looking for. but i promise i won't copy your car all the way
p.s. i used to go to school at jefferson county airport. loved living in broomfield

weather is getting nice again so a few of us roll over to JeffCo and have lunch periodically and watch the planes come and go on the patio. And I lived in SoCal (LA and OC) 'til 3 yrs ago so we just traded states... my tube chassis was built in Orange in '06 and that shop is now in Corona.


I was just spoofing on that you stated FWHP which would be front wheels I now realize you meant at the flywheel, or BHP (brake HP).

Hey Conversion Guys,

There is yet ANOTHER benefit to exhausting our the hood of the 914 that I forgot to pass on: the 12" trapezoidal piece defined by the hood support ribs weighed 5 LBS!!!
Ah!....More weight reduction!!

Terry

I didn't think to ask the owner what it was but a new mustang was parked at a whataburger in Belton, Tx. awhile back. I was in a hurry to get to nth austin and didn't hang around. It had a real nice hood vent that looked like it would be perfect on the 914. I have since looked for it online but haven't found it. It may have been a complete hood vent arrangement but it looked perfect for the 914.

I had the same experience with my six conversion. When I was running a 2.7 the front oil cooler was vented through the wheel wells. When the 2.7 went KABLAMMO! and the teener got a 3.2. The oil temps started getting over 210 even in Seattle. By venting the hot air up and out the hood, the oil temps went down over 25 degrees.


I didn't want to spend big buck on an full width oil cooler so I sourced a NASCAR refuge Setrab cooler that is only 13"x6"x2". This leaves room for brake cooling ducts on the outsides of the oil cooler opening. No loovers, just a wickerbill on the leading edge.

Cheers,

Eddie