CRASH
NAXJA Forum User
- Location
- Foresthill, CA
xj-grin said:
You are not making as much horsepower at your altitude, therefor not producing as much heat.
Stroker overheating
- Thread starter 92stroker
- Start date
You are not making as much horsepower at your altitude, therefor not producing as much heat.
CRASH
NAXJA Forum User
- Location
- Foresthill, CA
xjbubba said:
Exactly my point, a custom rad is necessary to make a stroker work under extreme conditions. Loaded, my truck weighs 5,500 pounds, plus another 700 in the trailer. In 110-15 degree ambient temps (common in the Northern Sacramento Valley in the summer), even crusing on level ground you are going to be using some HP to keep up a 75 MPH speed. Those kind of conditions REQUIRE more rad area/volume. I understand this, but have been trying to avoid the time and money it takes to make this happen.
SCW
NAXJA Forum User
- Location
- SLC (yuck) UT
xjbubba said:
PICS!!!!
If I may offer a cheap-ish idea to try?
Run a tank of premium fuel in the tank. Drive what you have until practically (best would be actually) empty and then fill it full of the high octane stuff. The idea is to get the gas feeding to the system as high an octane rating as possible.
Why? Often when installing a stroker crank and doing head work, the compression ratio is raised and the stock combustion chamber is designed to run on the low octane-rated stuff. From what you have said, to me it sounds like you are getting pre-detonation in the chamber, and when under a load, the pre-detonation is getting worse-typical of running too low a fuel rating with a higher compression motor. The On-board computer is designed to eliminate this condition by advancing or retarding the timing as well as adjusting the flow from the injectors. However, its designed to do this for a stock motor. All the extra cooling add-ons are helping, but are a band-aide to the central issue causing the overheating.
Adjusting the octane rating to meet the need of the specific engine is pretty common in racing applications where mixing different ratings of racing fuel are necessary to get the ideal octane rating of the fuel. NASCAR gets away with selling only one 'octane' rated racing fuel because it mandates the combustion chamber cc's as well as the max compression ratio the motor can run; ergo everyone needs the same octane rated racing fuel. Drag racers are not quite so bound by this handicap.
I used to run into this issue when I raced Air-cooled engines frequently and you'd be surprised at the amount of heat the wrong fuel rating for a given engine can create. Likewise, it'd run much cooler with the correctly rated fuel flowing through the system.
The easiest way to up your octane rating.....well, is to buy premium gas. If it doesn't work, you aren't out much (relatively speaking), but if it does....... The price one pays for having high-performance goodies,eh? :thumbup:
As a side note: do NOT use a bottle of octane boost to try the same thing. These products are NOT going to raise a tank of gas to 104 octane or whatever...all they do is inhibit the fuel's ingition, causing you to burn significantly less efficiently; which is why you added all these parts in the first palce-to run more efficiently
Run a tank of premium fuel in the tank. Drive what you have until practically (best would be actually) empty and then fill it full of the high octane stuff. The idea is to get the gas feeding to the system as high an octane rating as possible.
Why? Often when installing a stroker crank and doing head work, the compression ratio is raised and the stock combustion chamber is designed to run on the low octane-rated stuff. From what you have said, to me it sounds like you are getting pre-detonation in the chamber, and when under a load, the pre-detonation is getting worse-typical of running too low a fuel rating with a higher compression motor. The On-board computer is designed to eliminate this condition by advancing or retarding the timing as well as adjusting the flow from the injectors. However, its designed to do this for a stock motor. All the extra cooling add-ons are helping, but are a band-aide to the central issue causing the overheating.
Adjusting the octane rating to meet the need of the specific engine is pretty common in racing applications where mixing different ratings of racing fuel are necessary to get the ideal octane rating of the fuel. NASCAR gets away with selling only one 'octane' rated racing fuel because it mandates the combustion chamber cc's as well as the max compression ratio the motor can run; ergo everyone needs the same octane rated racing fuel. Drag racers are not quite so bound by this handicap.
I used to run into this issue when I raced Air-cooled engines frequently and you'd be surprised at the amount of heat the wrong fuel rating for a given engine can create. Likewise, it'd run much cooler with the correctly rated fuel flowing through the system. The easiest way to up your octane rating.....well, is to buy premium gas. If it doesn't work, you aren't out much (relatively speaking), but if it does....... The price one pays for having high-performance goodies,eh? :thumbup:
As a side note: do NOT use a bottle of octane boost to try the same thing. These products are NOT going to raise a tank of gas to 104 octane or whatever...all they do is inhibit the fuel's ingition, causing you to burn significantly less efficiently; which is why you added all these parts in the first palce-to run more efficiently
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
Over here the outside temp. in mid-afternoon has been hovering around 113-115*F. Under these conditions, my ~270hp 4.6 stroker runs a coolant temp of 210*F and an oil temp. of 175*F when cruising down the highway at 85mph with the A/C switched on.
At night time when the outside temp. is down to 95*F, the engine runs a coolant temp. of just 190*F and the oil temp. sits at 160*F with A/C on and driving at the same speed.
I can make the coolant temp. gauge creep up to 220 (A/C on, both electric fans working feverishly) and the oil temp. can also go up to 220 if I'm stuck in heavy traffic crawling at less than 20mph for more than 1/2 an hour.
The bottom line is that for all my cooling system upgrades, I don't have any cooling issues at least 98% of the time but the system IS marginal in extreme situations. My radiator is a custom 3-row unit that has the same frontal area as the stocker (31"x10.5" or 325.5 sq. in.). I can't see how a bigger radiator could fit without needing to perform some surgery to the bodywork around the radiator supports.
I'm sure that a bigger radiator plus two higher capacity electric fans would keep my stroker cool even in the most extreme conditions, but getting there ain't gonna be easy and will require a lot of fabrication work.
At night time when the outside temp. is down to 95*F, the engine runs a coolant temp. of just 190*F and the oil temp. sits at 160*F with A/C on and driving at the same speed.
I can make the coolant temp. gauge creep up to 220 (A/C on, both electric fans working feverishly) and the oil temp. can also go up to 220 if I'm stuck in heavy traffic crawling at less than 20mph for more than 1/2 an hour.
The bottom line is that for all my cooling system upgrades, I don't have any cooling issues at least 98% of the time but the system IS marginal in extreme situations. My radiator is a custom 3-row unit that has the same frontal area as the stocker (31"x10.5" or 325.5 sq. in.). I can't see how a bigger radiator could fit without needing to perform some surgery to the bodywork around the radiator supports.
I'm sure that a bigger radiator plus two higher capacity electric fans would keep my stroker cool even in the most extreme conditions, but getting there ain't gonna be easy and will require a lot of fabrication work.
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
StevenB said:
What you're saying is correct but that doesn't apply in my case. My stroker has a CR of ~9.4:1 and I'm running it on 91 octane fuel with no detonation. Air/fuel ratios are already optimized so nothing I can do there either.
Dr.Dyno- if it were me, I'd still try 93 octane for a couple tanks, just to see what happened. based on my expierences, a couple of points CAN make a difference. With the different fuel additives mixed in by the various vendors (yanno, to make 'their' gas better than the next guy's), it could affect the octane rating the motor sees. Meaning- you might be buying 91 octane, but its actually 90 that the motor sees; and would ideally want 92.
I'm no Jeep engineer, and don't play one on TV, but If you are starting at an ambient air temp of 115* ( :exclamati ), then a typical cooling system can only do so much with what it has to work with, eh?
I'm no Jeep engineer, and don't play one on TV, but If you are starting at an ambient air temp of 115* ( :exclamati ), then a typical cooling system can only do so much with what it has to work with, eh?
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
StevenB said:
We do have 94 octane (98 RON) over here as well as 91 octane (95 RON) but it's 10% more expensive than the lower grade. It might be worth a try on one or two tankfuls though just out of curiosity. I believe the fuel over here has MTBE in it so I don't know if that makes any difference.
StevenB said:I'm no Jeep engineer, and don't play one on TV, but If you are starting at an ambient air temp of 115* ( :exclamati ), then a typical cooling system can only do so much with what it has to work with, eh?
You've got that right!
goodburbon
NAXJA Forum User
- Location
- Westcliffe Colorado.
A trick I have used in the past for cooling when the stock radiator just won't cut it is:
1. Go to the local hardware store and pick up 6-5/8" nipples, 2 tees, and 8 hose clamps.
2. Go to the Auto parts store and pick up an old ford or chevy truck heater core and the hose to fit. They have different input/output tubing sizes, so just start opening boxes and find which one will fit your needs best.
3. Pick up a 9-10" cooling fan and necessary wiring/switch.
4. make a housing for the core (an old computer case works pretty well) and mount it under the hood somewhere.
5. Cut your heater hoses (on the engine side of the cutoff valve) and splice in the tee's, then splice in the core.
Presto, you have an auxilliary radiator for when the going gets tough, and it fts well where the stock airbox is.
1. Go to the local hardware store and pick up 6-5/8" nipples, 2 tees, and 8 hose clamps.
2. Go to the Auto parts store and pick up an old ford or chevy truck heater core and the hose to fit. They have different input/output tubing sizes, so just start opening boxes and find which one will fit your needs best.
3. Pick up a 9-10" cooling fan and necessary wiring/switch.
4. make a housing for the core (an old computer case works pretty well) and mount it under the hood somewhere.
5. Cut your heater hoses (on the engine side of the cutoff valve) and splice in the tee's, then splice in the core.
Presto, you have an auxilliary radiator for when the going gets tough, and it fts well where the stock airbox is.
SCW
NAXJA Forum User
- Location
- SLC (yuck) UT
Dr. Dyno said:
Have you thought about an oil cooler? I used to tow large loads with my 3/4-ton Ford that had and engine oil cooler and even drafting a semi while towing I couldn't make the thing overheat. It's soon to come on my Jeep because of heating issues while towing in the mountains.
Years ago I went to the Harrah's car museum in Reno, NV and saw a car that he had customized for him to drive in the winter around Reno. It was a Jeep Wagoneer with a Farrari V-12 engine, console, seats, steering, etc. As explained by the staff at the museum, the biggest issue was cooling the beast, and there was two smaller radiators added below the original slanted back to reduce ground clearance lost. Each new radiator was about 12" high x 18" long, as I remember.
j99xj
NAXJA Forum User
- Location
- Colorado Springs, CO, USA
CRASH said:
Engines can still overheat at high altitudes. My older brother roasted a Chrysler LeBaron about 10 years ago.
In fact I think cooling is slightly harder at high altitude. Since there is less pressure (ie less molecules of oxygen, nitrogen etc) the radiator has a harder time trying to transfer its heat to the air.
Root Moose
NAXJA Forum User
- Location
- ON, Canada
SCW said:
This is something worth having plumbed into the system even if it doesn't directly cure the problem that is occuring in the examples above.
Im kinda intrigued by StevenB's comments above. What cylinder heads are you guys with over heat issues running? Quench numbers and all that?
What I'm wondering about is if there is enough of a difference between HO and RENIX heads to make heat in the head an issue. I haven't layed an HO and RENIX head side by side... is the combustion chamber shape different (size and/or geometry) between the two?
Dr. Dyno
NAXJA Forum User
- Location
- Al Ain, UAE
An oil cooler would certainly be worth considering especially if you do a lot of slow wheeling offroad. I HAVE considered installing one myself but most of the time my oil temp. is below 180*F so I would only need it in extreme situations. If there was some kind of thermostatic control to prevent oil circulating to the oil cooler when it's below a certain temp., then it would be worthwhile.
An auxiliary radiator? Now that's an interesting idea! I'm gonna look into that, especially for those extreme situations (slow wheeling or climbing steep grades on a blazing hot day).
An auxiliary radiator? Now that's an interesting idea! I'm gonna look into that, especially for those extreme situations (slow wheeling or climbing steep grades on a blazing hot day).
SCW
NAXJA Forum User
- Location
- SLC (yuck) UT
Dr. Dyno said:
I'll use this when I install the oil cooler, which might be quite soon as I've been getting warm (not overheated yet, but close in 105 F).
http://store.summitracing.com/partdetail.asp?autofilter=1&part=DER-15720&N=115&autoview=sku
SCW
NAXJA Forum User
- Location
- SLC (yuck) UT
A little spendy, but very nice-
http://cgi.ebay.com/ebaymotors/Dera...014QQitemZ330002492894QQrdZ1QQsspagenameZWD1V
http://cgi.ebay.com/ebaymotors/Dera...014QQitemZ330002492894QQrdZ1QQsspagenameZWD1V
CRASH
NAXJA Forum User
- Location
- Foresthill, CA
I'm at 9.4 with spot on quench. Renix.
Root Moose said:
Talyn
NAXJA Forum User
- Location
- Radford, Communistwealth of Virginia
The reason I asked about a radiator is because with a high flow pump the fluid could be flowing too fast. I had that problme when I put in a high flow pump, high flow tstat and high flow t-stat housing, but left my stock radiator. It would over heat until I put in a stock flow t-stat. Might want to consider the flow rates there.
-Chris
-Chris
