LQ4 into a 3rd Gen/1972 Nova by frojoe

8 minute(s) of a 891 minute read

Part of my order today was the new rad & fans. I've gotten far enough along with the cardboard cooling stack mockup to know that there will be good room to make it work, so was time to move to the next step of getting parts.

Radiator is a 31"x19" overall size.. actually measures 31.0" wide by 18.625" high, and the core is 28.0" wide.

Reason for getting this particular radiator are:

1) has the widest core (28.0" wide) out of any of the popular brands' 31" rads, most common core size being 25.5-26.0" wide

2) C&R is a known and trusted brand. For my build I felt the price was only slightly higher than more questionable brands (Summit, Griffin, Entropy, etc) but I also couldn't spring for a big brand like BeCool, Ron Davis, etc. Welds are very consistent and tight, serial number and date of manufacture are hand engraved into the end tank. Multiple QC stickers.. everything points to a well-produced product

3) inlet & outlet are both on the same side.. I wanted to try a dual pass radiator just to see how it goes. Quite a few on the Corvette forums swear by dual pass for cooling when limited airflow is available.

The fan setup I'm trying out is about the beefiest setup I could conjur up... the highest-amperage Derale 16" fan paired with the highest-amperage 12" fan I could find.

The 16" fan is rated at 1918cfm but at 25.4amps, which is the highest ampdraw I could find out of any fan of any size, according to Summit but also searching manufacturers' websites and forum posts.

The second fan in the pic is one of my old ones (as a placeholder) which is 13" and 1640cfm @ 21.4amps. However the second fan I actually ordered and plan to try out (hasn't arrived yet) is a Derale 12" rated at a higher 2000cfm @ 24.8amps.

So total possible airflow (if the ratings are to be remotely trusted) is ~3900cfm, but at a whopping 50A. Luckily I already had the wiring setup to handle 70A continuous with a Ron Francis rad fan relay+fuse combo module.

I suspected that Derale fans are just re-branded Spal fans but about 25% cheaper, based off internet picture comparison, but it turns out that the fansare literally Spal fans just in a renamed box.

Rad is mocked up with spacers to the rad support to approx simulate a 4.5" thick intercooler, still not sure if I'm going to go that big. I'd really like to use a new-gen Garrett 3.8" thick intercooler core if I can find any core size that will work for my sizing.

I was anticipating some misalignment in the outlet/inlet, but it actually lined up better than I expected. Because everything on this damn car is custom, I'll give it a little effort to find a rad hose that might fit, but I'm expecting having to just cut off most of the rad inlet tube and weld on a bend to realign it perfectly with the waterpump outlet, and just use a straight rubber rad hose or maybe a black silicone coupler.

 

And fans appear to fit the accessory drive with a good 2-3" of clearance.

Like for the radiator lower inlet, I'm probably going to have to cut/weld on a tight aluminum 1.5" bend to the radiator outlet, to get the upper hose to hug the fans closely.

And fans appear to fit the accessory drive with a good 2-3" of clearance.

Like for the radiator lower inlet, I'm probably going to have to cut/weld on a tight aluminum 1.5" bend to the radiator outlet, to get the upper hose to hug the fans closely.

I also got a double-hump silicone coupler for the throttlebody, here's the backstory:

1) I originally got a 3.75"-to-3.5" reducer coupler that slid onto the throttlebody perfectly "just snug", but it didn't really have much give at all (for flex from engine motion, vibration, etc)

2) I then tried a 3.5"-3.5" single hump coupler, and I was able to stretch the 3.5" over the throttlebody's 3.75" OD without much issue, but in stretching the coupler it stiffened it up and removed a fair amount of give inherent in the hump design

3) So.. I now have a 3.5" double hump that is stretched over the throttlebody but still flexes side to side really nicely. I'll also be trimming the overall length down when I get to actually making the intercooler-throttlebody charge pipe.

It also looks like I'll have loads of room to hide the BOV underneath the charge pipe for a clean look, or if I want to bias the BOV to one side and have it rotated 45degrees from fully underneath (imagine at 4:30 or 7:30 position when viewed from front) if I want.

And finally got around to starting on the passenger side pre-turbo hotpipe. Yes, that's some laser alignment going on! Figured it was easiest reference to have once I confirmed that the laser was perpendicular to the center plane of the car via left & right distance measurements from both the firewall and the rad support. I also got the turbo's to the exact same height... 259mm height from the top of the subframe to the oil drain flange surface. Nerd!

I did some cutting and tack welding but ran out of time to tack on my last couple cut bends, but looks like the hot piping appear close to mirrored up until the final 90* bend into the T3 flanges.  

I think that with the wastegates up top, the wastegate dump pipes routed near the turbine housing and over the turbine inlet should help mask the remaining asymmetry in the turbine housing mounting area. I also like that both compressor housings will likely have the outlets pointing directly down, which could make them appear "lined up" side to side, in the absence of actual symmetry in the compressor housings

Ahhh.. here's a fun post to wrap up the weekend. I may cut the driver side wastegate hot pipe off and slacken the miter angle on it, to bring the driver side wastegate up a slight amount, currently it's just barely lower than the passenger side wastegate.