Grill block

[Hockey4mnhs]

Did you guys ever get loss of power or wierd rpm's with your grill blocks. I made a real quick one out of duct tape today to see what it would do but on the way home it seemed a little wierd. Idk if it is the tranny or the tape. the temp was fine didnt look any hotter than normal. what do ya guys think?

[DracoFelis]

Any chance your radiator fan(s) were coming on more, due to the heat?

If your block is "too big", than "too much" heat builds up, and than the radiator fan(s) come on to compensate (and keep the temp down). But when the fan(s) come on, your car will have more drag and likely higher RPMs due to the extra electrical load on the engine. If that is what is going on, you have two options (or a combo of the two) to deal with the issue:

1) Shrink the size of your grill block, as that is telling you your grill block is too large. The smaller you block, the more natural air will make it through the radiator to cool things. This will lower the aerodynamic benefits of the grill block, but it will also lower the heat buildup and therefore keep the fans (which cause electrical drag on the engine) from coming on so often! So it's a balancing act here.

or 2) Modify/replace your fan thermostat control to kick on at a higher temp. This will have the side-effect of letting your engine run a little hotter (i.e. letting a little more heat buildup), which may actually help FE a little bit more (as hotter engines are often more FE than colder ones). However, the down-side of this approach, is that it also risks damaging the engine if you get too hot. So this option is even more of a "balancing act" that option #1! If you want to do this, you clearly need to know what shape your engine is in, and carefully control other variables (for example, using high quality SYNTHETIC OIL, as synthetics better handle heat than traditional oils).

NOTE:
Various things can be done to help the engine handle higher temps. For example a nice clean (unsludged) engine will be better off with higher temps then a dirty engine. Likewise synthetics oils are better when you have extra heat, than regular oils are. So simply increasing the temp when the fan comes on isn't necessarily dangerous, if/when you do other things that help your car/engine handle the extra heat. But raising the temp does lower your "safety margin", so it's best to pay close attention to the other car/engine details if/when you choose that route.

BTW:
As soon as I figure out which wire to splice into (to control the fans), I'll be wiring up my adjustable radiator fan control IN SERIES with the existing controls. By doing things this way, the fan will never (no matter how I set things) come on more frequently than "stock", but I will have the option to dial back when the fan comes on (i.e. option #2) so things are allowed to get a little hotter in there). But OTOH I do use high end synthetics (which handle heat better), and I have a "bypass filter" (which also means more heat dissipation by the oil), and my engine is very clean and not sludged (in part do to the cleaning properties of the synthetics). So I'm pretty sure I can safely let temps raise some, without putting undo stress on my engine. Also my fan doesn't come on all that often anyway (mostly slower speeds in hot weather), so it's also the case that my previous attempts to shrink my grill block size (option #1) where at least partially effective. So while I'm currently only using option #1, I intend to use a combo of the two options "soon"...

Edit (8/6/2007):
My mechanic was over doing some last minute work on my car before a long road trip (vacation) my wife and I are taking later this month. While he was over, he brought a photo-copy of a wiring diagram (dealing with the car's fans) he got from a dealer. With that wiring diagram, it was trivial to figure out which wire to tap into, to make the radiator fan temp setting adjustable. So as of this evening, I now appear to have an adjustable radiator fan control! I've started off somewhat conservatively on the control, and I figure I'll keep adjusting the temp (when the fans kick on) up in small increments, until I see a rise in the dash temp meter while driving (then back off a bit). That should hopefully allow me to reach the optimum fan temp setting by simple "trial and error" (i.e. continuing to make small adjustments until I have gone "too far", then backing off a bit).

[holypaulie]

Originally Posted by DracoFelis

Any chance your radiator fan(s) were coming on more, due to the heat?

If your block is "too big", than "too much" heat builds up, and than the radiator fan(s) come on to compensate (and keep the temp down). But when the fan(s) come on, your car will have more drag and likely higher RPMs due to the extra electrical load on the engine. If that is what is going on, you have two options (or a combo of the two) to deal with the issue:

1) Shrink the size of your grill block, as that is telling you your grill block is too large. The smaller you block, the more natural air will make it through the radiator to cool things. This will lower the aerodynamic benefits of the grill block, but it will also lower the heat buildup and therefore keep the fans (which cause electrical drag on the engine) from coming on so often! So it's a balancing act here.

or 2) Modify/replace your fan thermostat control to kick on at a higher temp. This will have the side-effect of letting your engine run a little hotter (i.e. letting a little more heat buildup), which may actually help FE a little bit more (as hotter engines are often more FE than colder ones). However, the down-side of this approach, is that it also risks damaging the engine if you get too hot. So this option is even more of a "balancing act" that option #1! If you want to do this, you clearly need to know what shape your engine is in, and carefully control other variables (for example, using high quality SYNTHETIC OIL, as synthetics better handle heat than traditional oils).

NOTE:
Various things can be done to help the engine handle higher temps. For example a nice clean (unsludged) engine will be better off with higher temps then a dirty engine. Likewise synthetics oils are better when you have extra heat, than regular oils are. So simply increasing the temp when the fan comes on isn't necessarily dangerous, if/when you do other things that help your car/engine handle the extra heat. But raising the temp does lower your "safety margin", so it's best to pay close attention to the other car/engine details if/when you choose that route.

BTW:
As soon as I figure out which wire to splice into (to control the fans), I'll be wiring up my adjustable radiator fan control IN SERIES with the existing controls. By doing things this way, the fan will never (no matter how I set things) come on more frequently than "stock", but I will have the option to dial back when the fan comes on (i.e. option #2) so things are allowed to get a little hotter in there). But OTOH I do use high end synthetics (which handle heat better), and I have a "bypass filter" (which also means more heat dissipation by the oil), and my engine is very clean and not sludged (in part do to the cleaning properties of the synthetics). So I'm pretty sure I can safely let temps raise some, without putting undo stress on my engine. Also my fan doesn't come on all that often anyway (mostly slower speeds in hot weather), so it's also the case that my previous attempts to shrink my grill block size (option #1) where at least partially effective. So while I'm currently only using option #1, I intend to use a combo of the two options "soon"...

3) concentrate your coolant to 40/60 ratio to transfer more heat per cycle http://www.challengers101.com/CoolantMix.html

[Hockey4mnhs]

hmm so it might be to much block ill check it out after this tank.

[DracoFelis]

Originally Posted by holypaulie

3) concentrate your coolant to 40/60 ratio to transfer more heat per cycle http://www.challengers101.com/CoolantMix.html

That might help if you also adjusted your fan temp sensor, to only come on at a higher temp. And likewise additives such as RedLine's "Watter Wetter" might also help, again if (and only if) you adjust the temp sensor upwards a few degrees (possibly requiring a replacement temp sensor, because most car sensors have a fixed setting they trigger at)

However, the (subtle) problem with just adjusting the coolant mix and/or using a product like "Watter Wetter", is that both approaches actually make the coolant itself hotter (even though both approaches have the beneficial effect of lowering the engine temp, the coolant temp actually goes up more than it otherwise would, because more of the engine's heat is being carried away by the cooling system). And since most fans are controlled by temp sensors that measure the coolant temp (not the engine temp itself), this actually has the undesirable side-effect of causing the fans to turn on SOONER than they otherwise would.

OTOH if you adjust your coolant mix (and/or use an additive such as "Water Wetter"), and also raise the coolant temp setting that the fans come on at, you might get the best of both worlds. Because those approaches will allow the coolant to work more efficiently, while at the same time you can still avoid the "fan coming on too soon" problem by simply adjusting up a bit (an extra 10 degrees, maybe?) what coolant temp the fans are set to trigger at...