Summer LS Swap

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Funco4JM

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Hey all,

Over summer I decided that I will do an LS swap into my Gen4. I have already purchased the LS1, it is complete out of another running sand car. Nothing special, stock LS1 with Painless harness, corvette computer running all sensors, Painless fuse block and relays, OBDII port, Intake with MAF, headers, adaptor plate and clutch. Should be easy for the most part. 

This is my list of things to Fab or Change -

Engine mounts to be fabbed

Coolant Lines to be fabbed

Replace Bosch -6 fuel system with Aeromotive -8 (A1000, pre/post filter, regulator and all new -8 fittings/hose)

Weld in -4 bung in coolant purge tank for LS steam port line

Change fans on CBR radiator from 14" (Circa 2004) to new 16" Hi Performance fans

Replace P/S lines due to pump location change and attached resi vs remote resi

Battery option - Add second Odyssee PC925, or remove existing PC925 and install a single Optima full size? Any recommendations on this?

For those of you who have LS swapped a Gen4, what where some of the struggles you encountered? 

Thanks in advance!

 
Fans, don't go by the mfg's cfm rating.  Look at current draw.  It will give you a better idea of the motor size, and how much work it's actually doing.  Something like this is good.

Battery, I wouldn't trust an Optima to function as a door stop...

 
Kraut_n_Rice


I don't see any CFM or Current draw specs.  What have you seen as far as normal to Brushless comparisons?

Do you think the extra coin is worth it?


 

 
Last edited by a moderator:
Kraut_n_Rice said:
Fans, don't go by the mfg's cfm rating.  Look at current draw.  It will give you a better idea of the motor size, and how much work it's actually doing.  Something like this is good.

Battery, I wouldn't trust an Optima to function as a door stop...
Click to expand...
Good to know... May not go the route of Brushless due to the additional wiring and sensors needed. I may not even need new fans, I am just thinking the 14" fans that are 18 years old may need to be replaced with some 16" modern units. 

On the battery, what would you suggest? A different brand large group single, or dual odyssee PC925? Full disclosure, I already have a 2nd PC925 and battery box. I was going to pass it along to a buddy and use my original PC925 battery on my trailer to power my fuel drum pump, if I went the single battery route.

 
HTElectrical said:
Yeah Right :classic_blink:   I almost did on my recent upgrades, but ran out of money.  At $300 per 12" fan, and another coupe hundred for controller they are spendy..
Click to expand...
A friend of mine always says a crack addiction would be cheaper than playing in the sand... I'm starting to believe that Lol. 

 
HTElectrical said:
Kraut_n_Rice


I don't see any CFM or Current draw specs.  What have you seen as far as normal to Brushless comparisons?

Do you think the extra coin is worth it?


 
Click to expand...
The spal link I provided has all the data in a graph.  It's metric, but it's there.  That fan is just under 35 amps and 2400cfm.  The nice thing about the brushless fans is they are progressive.  They vary the speed with temperature.  You would only need to run a 40 amp fuse because there is no huge in rush of current on start up.  With the sensor options you can try to target your engine temps, and you only need one.  They can control up to 12 fans each.

Price wise, the brushless are not quite double.  Worth it?  Judgment of the person spending the money.

There are devices on the market that will make you brushed fans operate like brushless.  Soft start fan controllers that will also vary the fan speed by a user programmable setting.   

 
Jtmoney714 said:
I can help you with some savings… unless you already have the a1000 I think you would be better served with an aem fuel pump. I run it on my stroker and even with an e60 blend of fuel it was plenty of fuel pump. 
 

https://www.amazon.com/AEM-Electronics-50-1009-Inline-Flow/dp/B077JJ2Z5C/ref=mp_s_a_1_4?crid=1KLULDYJ45BSL&keywords=aem+400lph+fuel+pump&qid=1647647218&sprefix=aem+40%2Caps%2C139&sr=8-4
Click to expand...
I already have the a1000. Thanks for the info tho!

 
I run a single pc925 on my Gen 4 with a Stroked LS2.   I don't have a lot of electrical accessories (stereo, heated seats, etc) but it always starts the car no problem.

 
Well, the process has begun... Started with removal of the Honda V6 and its accessories. This I found to be the easy part... 

Honda.jpg

For mock-up I did not install the clutch as I have to change the throw out bearing and do some cleanup in the bay. It will come out once or twice before going back in permanently. 

LS.jpg

It went in with no issues. I quickly installed the rear cage to check clearance, no issues there other than the intake elbow. There is just not enough room from the TB to cage to make the elbow fit. I do have to rotate the intake 180* and that is where the problem began. I was excited and didn't stop to think of potential issues, not thinking about the sand build up under the intake, I removed the harness and unbolted the intake. Popped the PCV system off and grabbed the intake to remove... Thats when the gallon of sand that was under the intake flowed into all 8 intake runners and into my cylinders... Or some of them anyway. As I sat there cursing myself for not thinking things through, I realized the worst part was having to buy new gaskets. I'll just blow it apart, clean it and reassemble it. Being April, I still have plenty of time before the season starts *knocks on wood*. 

With that nonsense to deal with, I am pondering should I spend the $$ and have the 243 heads ported while they are off? It is a stock bottom end LS1 with a GM Performance Cam and springs. The intake is an LS6 with a stock 78mm throttle body and GM computer. I planned on pushing it to 383 cubes next year (can't swing that this year) but I might swing the heads now. Would it even be worth it with the 78mm throttle body?!

I already began the purchase of parts and items I would need for the swap. Fuel system is mostly here with just a fuel pump on its way, I wanted to go a little overkill in case I ended up with TT on E85 or something crazy, so all new -10AN fuel feed lines, Aeromotive filters, brushless Aeromotive fuel pump and Aeromotive X1 Regulator. I'll have to replace the existing 3/8NPT bung with a 1/2NPT bung on the fuel tank to feed it. The return line will be -8AN from the regulator to the tank. No changes there needed. 

Next thing to figure out is coolant lines... What are your thoughts on hard lining them vs. -16/-20 hose? The hose is very pricey compared to hard line fab. Since my current radiator uses an expansion tank, I will have to weld on a -4AN bung for the steam port line coming from the LS. I also need a bung added to the lower radiator hose for the expansion tank to drain back to. This is where the coolant line material comes into play. If it is hardline, I weld in a bung for an AN feed. If it is a soft line, I will have to have some sort of break in the line where a feed bung can be added, then soft line to radiator. 

I decided to just add a second PC925 to the car. Ordered a Funco battery box to add to the passenger side of the Forin. That will make it easy to wire into the new battery disconnect switch. 

I'll try to get some pics of stuff as it comes in. 

 
Funco4JM said:
Well, the process has begun... Started with removal of the Honda V6 and its accessories. This I found to be the easy part... 

Next thing to figure out is coolant lines... What are your thoughts on hard lining them vs. -16/-20 hose? The hose is very pricey compared to hard line fab. Since my current radiator uses an expansion tank, I will have to weld on a -4AN bung for the steam port line coming from the LS. I also need a bung added to the lower radiator hose for the expansion tank to drain back to. This is where the coolant line material comes into play. If it is hardline, I weld in a bung for an AN feed. If it is a soft line, I will have to have some sort of break in the line where a feed bung can be added, then soft line to radiator. 
Click to expand...
Actual expansion tank with a pressurized cap, or just an overflow bottle?

 
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