89 911 LS1 Conversion

[Yan2947]

Thanks! And tell us a little about your Mercedes...

[drmatera]

well, traffic was crazy and the weather sucked last night but I did manage to drive thru my neighborhood in 2nd gear going from 3200-3500rpm. People thought I was nuts. I found out 2 interesting things:

1) temp goes from 196* to 198* within the first 15-20 seconds but stabilizes there. Now I didn't do it for 5 miles/5 minutes as I just didn't have the real estate to pull that off.

2) Why on earth would you even consider running 4000rpm down the road for any period of time? Change the gear ratio

[Yan2947]

Well, 4000 rpm is 80 in 5th gear. I agree, all these conversions should swap out at least 5th gear.

[lin7310948]

my conversion with the radiator in front runs 180-190 on hot days on the interstate. but with the 930 transaxle i am only turning 2200 rpms at 70 mph. and my car has a small frontal opening as it is a ruf yellowbird front spoiler and i dont want to cut the opening larger! the engine is a mast motorsports ls7...427 cubic inches..and makes 700 chp!

[Yan2947]

Larry, can you drive down a nice road in a low gear at 4 rpm for about 5 miles and let me know your temp. If we all have hi temps then it is all about gears.

Yan

[Yan2947]

Does anyone have instructions/photos/video for a g50/01 5th gear swap. I am looking for a real tall gear for highway quiet and low rpm.

Thanks

[drmatera]

my tuner also said it sounds like a fuel or timing issue. High rpm and low load needs a decent amount of timing

[Yan2947]

Already nicely tuned to correct the issue. I think (and may be wrong) that all of the ls setups will get hot around 4000 rpm (especially after 5 to 10 miles) unless they have a large radiator. Tall gears probably solves all the issues and should be a priority in all swaps. These motors like to run with low rpms I think...

[Lapkritis]

Originally Posted by drmatera

my tuner also said it sounds like a fuel or timing issue. High rpm and low load needs a decent amount of timing

Seconded. Setup depending, I keep 34-40° advance in cruising bins. An EGT probe can help dial in a nice, safe burn.

[drmatera]

Originally Posted by Yan2947

Already nicely tuned to correct the issue. I think (and may be wrong) that all of the ls setups will get hot around 4000 rpm (especially after 5 to 10 miles) unless they have a large radiator. Tall gears probably solves all the issues and should be a priority in all swaps. These motors like to run with low rpms I think...

yessir

my Benz cruises down the highway at close to 80mph well under 3000rpm

[lin7310948]

yan it is rainy in our area. maybe i can make a run later in the week. as a note, i did not use the renegade hybrids radiator. i had the radiator built by griffin which is very close to me. i had it built as large as i could fit into the frontal opening. it is sealed to the sides and to the inner fenders as well as the hood. seems the faster i go the better it cools. probably due to the relatively small opening in the ruf front spoiler!

[Yan2947]

Larry, what size radiator and fan setup did u use? I am not worried about speed with anyone. Gear size totally makes a difference. I am hoping just even going slow at 4000 rpm for say 5 to 10 miles will show the true temps of the car. I know the car gauges are never perfect but hoping you have a computer of some sort hooked up. I use my iphone with Rev2 and a wifi adapter with the obd2 but anything that reads the temp is fine. If someone with a good radiator setup gets hot with high rpms then it really is all in the gears... Thanks!

Yan

[Mitch Leland]

I'll chime in on this, I have 3 radiators on my 966 C4S, now C42. I had a taller ring and pinion installed, in 6th gear I'm showing 80 MPH 2,375 RPM . My temp at highway speed never gets over 190 degrees even in 100 degree temps. However my oil gets hot, at the same temps it will go to 260 degrees. Am in the process of looking into an oil cooler.

I noticed that pulling a grade in 95-100 temps that the oil temp rises quickly. I just returned from 4,000 mile trip in the car so I had lot's of time to look at all of this.

Bottom line, unless you're going to drag race your car, I would go for the taller gears, changing the ring and pinion changed all of the gearing, expensive, but well worth it... At 70-80 MPH my car is quieter than with the 3.6 engine, mostly because the RPM's are lower.

[Yan2947]

Mitch, thanks for chiming in. You have two of your radiators in your front fenders (stock)? Do you have photos of that portion of your setup? I am wondering if I added an additional radiator in a front fender in my 89 911. Would I need to cut anything to vent or are they just naturally vented in the fender and what size are they? Fans? Or would a center front radiator require or work with a stock valance with a cutout of the valance (this being just an extra radiator).

I do plan on getting the taller 5th gear but I know I must be very close to a fully working setup already and with slightly extra cooling I may be able to maintain temp at any rpms. Not that I plan to ride hard at high rpms but if I conquer the temp issue now I won't have any issues with added hp later. I have thought of adding an extra cooler in the rear right fender or one of the front ones. Just not sure which way to try.

Is there any chance you could ride your car at the higher rpms for about 10 miles (4000 rpm) and let me know what you reach? Do it a slow speed or any speed. I have trouble understanding why no other person has chimed in after doing this. I don't think 4000 will hurt anything even though it may be a bit loud... It will give me a starting point with what size radiator really works!

[Mitch Leland]

Originally Posted by Yan2947

Mitch, thanks for chiming in. You have two of your radiators in your front fenders (stock)? Do you have photos of that portion of your setup? I am wondering if I added an additional radiator in a front fender in my 89 911. Would I need to cut anything to vent or are they just naturally vented in the fender and what size are they? Fans? Or would a center front radiator require or work with a stock valance with a cutout of the valance (this being just an extra radiator).

I do plan on getting the taller 5th gear but I know I must be very close to a fully working setup already and with slightly extra cooling I may be able to maintain temp at any rpms. Not that I plan to ride hard at high rpms but if I conquer the temp issue now I won't have any issues with added hp later. I have thought of adding an extra cooler in the rear right fender or one of the front ones. Just not sure which way to try.

Is there any chance you could ride your car at the higher rpms for about 10 miles (4000 rpm) and let me know what you reach? Do it a slow speed or any speed. I have trouble understanding why no other person has chimed in after doing this. I don't think 4000 will hurt anything even though it may be a bit loud... It will give me a starting point with what size radiator really works!

Yan,

Where I installed the 3rd radiator in my 966 won't be the same for your 911... I used the same mounting brackets as the factory "Tiptronic" oil cooler mount. I then connected the 3rd radiator in series with the two factory radiators.

Right now I have the car on my lift working out the new oil cooler so it's not going anywhere any time soon. I had 3 weeks of fun driving so I'll give it a rest while I do some more upgrades.

The only thing I can say is you can't have too much cooling capacity, why not change out the ring and pinion instead of the 5th gear. Then you have taller gearing through out the RPM range. If nothing else I would consider taller wheels...

I would also consider an oil cooler, my LS3 motor only holds 5 qts of oil and being in the rear of the car I don't think it's getting the same airflow as a front engine install. I know the same LS motor in the current 2014 Corvette is a dry sump engine. The point here is if you want a factory operating, everyday car I think you need to look at all of these options. If you just want a 0-60 hot rod then you don't need some of this.

[Yan2947]

Mitch, what is the H x L x D of that center radiator? I wonder if I could run one in series with my rear one. No fan on it? No venting in back? Do you have the part number for it and the brackets? Would it fit on my 89?

The rack and pinion is a bit expensive right now. I have been restoring a 52 MB...

1952 220 Sedan W187 build restoration

So funds will have to wait and the one gear is not too bad.

[Mitch Leland]

Yan,

I can't find the dimensions right now of my 3rd radiator. I've got shop drawings and details but I just can't lay my hands on them right now. But I can tell you my radiator that I had custom built will "not" fit your car. It's not vented as my radiator system is a closed system. And I don't have a fan on the new 3rd radiator. So far it doesn't seem to need one. However once I get my oil temp uncontrol I'll revisit that.

[Yan2947]

Mitch, Just looking at my setup with my stock valence/spoiler - you are right - won't fit. I purchased this front spoiler from Better Bodies a while ago. I know that the cooler would fit with it but I really like the stock look. Thoughts? It would allow for the extra cooler. I also attached a CBR cooler from ebay that says:

CBR PERFORMANCE COOLING PRODUCTS SMALL OFF-ROAD OIL COOLER -10JIC W/ 9" SPAL FAN
8"X9.5"x2.25 Fans- Single 9" SPAL

If I could mount it somewhere it would be great as a second radiator mounted in series also. The rear right fender may work or near the rear bumper. or just the taller 5th gear...

[ChrisP911]

Have you had any luck with your cooling.

[Yan2947]

Everything cools well except at the 4000 rpm range. I am going to add a front center 996/997 radiator and see if that is an immediate fix. Steve at renegades is always a help even with my toy jet setup. I am going to run some inch and a quarter lines up front and mount it temporarily, running it in series. If that solves the cooling then I will add the radiator into my spoiler or my 935 spoiler. This will tell me if I have or don't have enough square inches on my radiator... After that is solved I can add a tall gear also.

Not a single person did the 4000 rpm challenge! 😞