Upgraded radiator => strange underhood noises: FIX

[treynor]

Upgrading your stock radiator to a thicker Fluidyne (or similar) while retaining your stock airbox introduces a clearance problem between the bottom of the airbox and the fan shrouding. This most commonly manifests itself as a growling or whirring sound once the car is warm, especially when the steering is turned one way or another. The problem is, once the fan shrouding is cut away to accommodate the airbox, the fan blades will contact the bottom of the airbox when the engine and/or radiator shifts slightly:

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There are three basic solutions:
1) Replace the stock airbox;
2) Modify the stock airbox;
3) Replace the cooling module.

I chose option (3) because I wanted more cooling power when in traffic, and I wanted to retain the airflow and rain-resistant features of the stock airbox. Valaya Racing (408.448.8811) sells an excellent cooling module upgrade, and it has the side effect of eliminating the clearance problem associated with the OEM module and a larger radiator. I've included a few pictures to show how it fits:

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Here you can see the space available with the Fluidyne installed and the OEM cooling module removed. Note also the stock oil cooler (that black thingie just above the brace).

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Here is the "after" shot, with the two new fans replacing the stock single fan. Each of the new fans pulls as much or more CFM as the OEM fan alone, which really keeps the temps down in traffic.

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A second "after" shot, showing just how much space is now available. I could practically get -two- airboxes in there

Needless to say, there is no more interference problem. A simple wiring harness plugs into the stock fan turn-on lead and activates the dual fans. Alternatively, you can wire it with a manual override switch to turn on the fans from inside the cockpit (good for drag racers) or using an external temp sensor.

obAside: my dyno testing has shown that, at least on '01 models, keeping engine temps below 190 picks up 10-20 RWHP compared to temps over 200. After tubes + filters, a radiator+thermostat+fan swap is the cheapest way to pick up real-world HP on the Viper.

 

[King GTS]

You mentioned that you replaced the cooling module. What did you replace it with?

 

[treynor]

"Cooling module" is the name for the combination of OEM fan + shroud + rubber flapper doors. In this case, it was replaced with the two smaller fans you see mounted in the last couple pictures.

For a side-by-side comparison:

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[Eddie N]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by King GTS:
You mentioned that you replaced the cooling module. What did you replace it with?

<HR></BLOCKQUOTE>

i believe the cooling module is the OEM fan..

treynor,

did you switch out the oil cooler with a roe racing unit as well? i cant really tell in the pictures..

definitely a worthly modification.. im into efficiency mods as much as im into performance mods.. anything to make the car run better is a good investment to me!

- eddie -

 

[cstegall]

Ben,

Thanks for the info. and pics. I have been thinking of doing the same thing and wondered what problems might occur.

No Flame Intended...Just Observation,

CStegall

 

[treynor]

I swapped the OEM power steering fluid cooler for the Roe Racing cooler. It's about 60% larger than the stock unit, and since we were already digging around in there it made sense to do so. The engine oil cooler is actually way up in front of the main radiator, and that remained stock.

 

[Eddie N]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by treynor:
I swapped the OEM power steering fluid cooler for the Roe Racing cooler. It's about 60% larger than the stock unit, and since we were already digging around in there it made sense to do so.
<HR></BLOCKQUOTE>

thanks for clearing that up!!

that civic is going DOWN!!

- eddie -

 

[King GTS]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by treynor:
"Cooling module" is the name for the combination of OEM fan + shroud + rubber flapper doors. In this case, it was replaced with the two smaller fans you see mounted in the last couple pictures.


For a side-by-side comparison:

You must be registered for see images

<HR></BLOCKQUOTE>

Oooohhh, I see! Thanks.

 

[Mike L]

It would be interesting to see what effect mounting the new fan cooling module to a stock radiator produces (if it will fit). If you increase the CFM's substantially, wouldn't that make a big difference even with the stock radiator?
Mike

 

[Doug Supercharged Vipers]

Ben -

Call me at the shop, I'll be there Sat & Sun.

Great job and thanks sharing!

Doug

 

[Ron]

<FONT face="Comic Sans MS">Thanks Ben, now I know where my 20 HP went.

I dyno'd my 1996 GTS at the 2K mileage mark and had an SAE corrected 412, stock. Dyno'd again last week at 8.5K miles and had a 403 number, again SAE corrected. Needless to say I was disappointed. I suspected heat was the issue as on the earlier run we hooked everything up and let the car cooldown with an external fan on and the hood up for 15 ~ 20 minutes. The recent pull required the engine to idle for 15 minutes before the operator could figure out how to get an RPM reading from the V10, which he had no familiarity with. My rad fan never came on during the earlier pull while the recent pull had the fan on high the whole time, plus I had the heat on full blast to try to cool it down.

Next time, complete cooldown before the pull!
</FONT f>