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93 Crew Cab Build

Thanks for the suggestions. I ordered another walbro today to give it another shot. I'll probably run -8 lines from tank to filter to pump and see how it goes. Pretty excited to hit some trails soon once the fuel system is sorted out. The caddy motor is thirsty and that fitech must have 60 psi all the time or it falls flat on power.

Didnt have much time over the weekend to work on it. Drove it around some with the family loaded up. Welded in some tabs for the limit straps today. Gonna make a simple battery tray and get that secured this week. Next big task is trimming off the cowl and fitting a hood and dash/console. I have a box of switches and electrical junk to add. I even have a cig lighter and USB charger. Gonna do my best to have a luxury ride.
 
dignifiedWT said:
Thanks! Anyone want to share their opinion on the exhaust? I had cheap turbo mufflers before and don't want to put them back on. They seemed too restrictive. A good friend has 2 pairs of flowmasters he has offered to donate. Both are 3" pipe, one set is 13" long and the other 17" i think. I'm kind of leaning toward running the short ones. Currently I have 2.5" from the headers back past the t-case. Figured I'll run 3" duals from the mufflers back past the axle/rear bumper. Anyone think that will be too loud for trail riding? The other option I have in mind is to install a pair of cut-outs in front of some quiet mufflers. I figure that might be beneficial if I ever take this to go hog hunting, etc... I'm open to suggestions.
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Personally wouldn't run duel exhaust. A (Y) pipe or crossover helps with efi tuning, but thats my opinion and someone may say different.

Run a 3 or 4 inch single exhaust to a 4" diesel muffler like a Donaldson, or go to the local big rig shop and see what's on the shelf that fits. Awesome build.
 
dignifiedWT said:
Thanks for the suggestions. I ordered another walbro today to give it another shot. I'll probably run -8 lines from tank to filter to pump and see how it goes. Pretty excited to hit some trails soon once the fuel system is sorted out. The caddy motor is thirsty and that fitech must have 60 psi all the time or it falls flat on power.
Click to expand...

Maybe fuel sloshing or off angle fuel starving? Had this problem before killing pumps. I cut a 3" hole in the bottom of the fuel cell, weld on a deeper sump to feed.
 
dignifiedWT said:
Thanks! Anyone want to share their opinion on the exhaust? I had cheap turbo mufflers before and don't want to put them back on. They seemed too restrictive. A good friend has 2 pairs of flowmasters he has offered to donate. Both are 3" pipe, one set is 13" long and the other 17" i think. I'm kind of leaning toward running the short ones. Currently I have 2.5" from the headers back past the t-case. Figured I'll run 3" duals from the mufflers back past the axle/rear bumper. Anyone think that will be too loud for trail riding? The other option I have in mind is to install a pair of cut-outs in front of some quiet mufflers. I figure that might be beneficial if I ever take this to go hog hunting, etc... I'm open to suggestions.
Click to expand...

Unless your turning the caddy motor past 7000 rpm a dual 2.5" exhaust is plenty. 3" won't help buy may hurt low end. Flowmasters don't flow that well and may be worse than your existing turbo (straight through) mufflers. Put in a V-band so you can try different mufflers/combos. Suggest longer case muffs.

I intentionally build an appropriate sized 'truck' exhaust system for my 466, 1.75" L&L headers into 2.5" tube, into a 2-into-1 muffler with single 3" out.
 
rattle_snake said:
Unless your turning the caddy motor past 7000 rpm a dual 2.5" exhaust is plenty. 3" won't help buy may hurt low end. Flowmasters don't flow that well and may be worse than your existing turbo (straight through) mufflers. Put in a V-band so you can try different mufflers/combos. Suggest longer case muffs.

I intentionally build an appropriate sized 'truck' exhaust system for my 466, 1.75" L&L headers into 2.5" tube, into a 2-into-1 muffler with single 3" out.
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I would assume the turbo mufflers he is referring to are this style, not the bullet style mufflers you are thinking of.

https://www.dynomax.com/mufflers/super-turbo-mufflers

Not that I am a exhaust expert, and I didn't stay at a Holiday Inn Express last night, but I believe the "backpressure" myth has been disproven at this point. Specially on a large displacement motor such as this, the 3" will only help. Engine Masters has shown this a few times in the recent few years I believe.
 
I am on board with running a single exhaust. Routing it past the links and over the axle will be harder with duals, plus the fuel pump is in the way on one side now. I don't want to choke the motor any. Toreadoranger is correct about the muffler style I have. The engine seems to be much snappier without the mufflers on, so I'd like to find something that flows better. 3" single is probably fine. I doubt the engine has much more that 400 hp and its not revving past 5K without exploding. Running 4" seems crazy. Might do like rattle_snake's, but go dual 2.5" into a 3.5" single.

I watched the Engine Masters episode on mufflers a while back. The turbo mufflers were dog shit on the dyno!

Another question: should the O2 sensor go behind the Y-pipe on a single exhaust setup, or is it more important to have it closer to the collector?
 
dignifiedWT said:
Another question: should the O2 sensor go behind the Y-pipe on a single exhaust setup, or is it more important to have it closer to the collector?
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Looking at factory efi setups most are mounted close to the collectors.
 
Gravy said:
Not so much backpressure but exhaust scavenging. Engine masters test peak power and tweaks the tune for dyno numbers.
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They evaluate under the curve and have done a few tests where they don't change anything but the exhaust piping between runs as they were specifically testing the change in the exhaust size. I guess this is an excuse to go back and rewatch those.
 
dignifiedWT said:
I am on board with running a single exhaust. Routing it past the links and over the axle will be harder with duals, plus the fuel pump is in the way on one side now. I don't want to choke the motor any. Toreadoranger is correct about the muffler style I have. The engine seems to be much snappier without the mufflers on, so I'd like to find something that flows better. 3" single is probably fine. I doubt the engine has much more that 400 hp and its not revving past 5K without exploding. Running 4" seems crazy. Might do like rattle_snake's, but go dual 2.5" into a 3.5" single.

I watched the Engine Masters episode on mufflers a while back. The turbo mufflers were dog shit on the dyno!

Another question: should the O2 sensor go behind the Y-pipe on a single exhaust setup, or is it more important to have it closer to the collector?
Click to expand...

Id take a look at the Magnaflow Straight through mufflers. Get the biggest case one you can fit.

Gravy said:
Looking at factory efi setups most are mounted close to the collectors.
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Most Factory setups run multiple O2s, so they can monitor each bank. Which it sounds like he only has a single sensor. I could be wrong but it would seem odd to me to monitor only a single bank of the motor by putting the O2 up that far on a single setup.
 
I personally have yet to see any evidence that running "too big" of an exhaust hurts low end power (at least appreciably). Obviously though, you will start to see diminishing returns. I don't think any of the sizes that have been discussed her are overkill for a 500ci V8.
 
Some people remove cats and re-install just for emission testing. Obviously the cats induce more back pressure. Low end torque increase from cats can be very noticeable, guessing ~15% to be able to feel in seat of pants. You results may vary. Most dyno result don't show much below 3000 rpm or any part throttle behavior, but this is 95% of driving conditions.

But it all comes down to the specific vehicle and use. So if you have the data/experience that suggests your motor performs better with less restriction go for it.
 
I ran full length 1.75" l&l headers into dual (kink bent) 3" into single 3.5" then into 4" in my old 76 ford with warmed up 472.
I ran two different mufflers, the one in this video (circa 2006 hence the awesome quality) was a single 4" straight thru dynomax with apprx 9" case and about 30" long.



I had it set up where i could easily switch in a stock 99-03 7.3 powerstroke 3.5" muffler using band clamps. It made the truck much quieter and had a nice rumble still. I could not tell a difference in power driving on the street.

I guess what im saying is i recommend a single, and dont over think it.

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Made a battery tray and another aluminum panel to hold the rear license plate today. Went on an extended test drive and the fuel pump made all the difference. Runs awesome.

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Finally found something to flex out on. The front end flexes decently enough. Obviously the rear does most of the articulation, but its more balanced than I expected it to be. The clearance between the rear tire and the coil over is tight but I can live with it. For reference the front springs are X code super duty fronts from a 2004 supposedly. Rear I'm running 175/200. In these pics the rear is maxed out. Pass side looked to be fully compressed. Driver side tire just lifted.

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When you first built your cage did you run it through the dash? or just pull the dash? I'm trying to figure out which way I want to go with my 88. There isn't much on the dash that's of use to me at this point.
 
Toreadorranger said:
When you first built your cage did you run it through the dash? or just pull the dash? I'm trying to figure out which way I want to go with my 88. There isn't much on the dash that's of use to me at this point.
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I ripped the dash out completely. It was pretty busted up. Gave me a lot more room to put the cage in later. My original plan was to build the cage tied into the cab, build a tube dash/console into the cage/seat frame.
 
wicked to see this build over there and the new changes are awesome :smokin:
 
Added a T case brace and crude crossmember to support the back of the NP205. Never had one before but i never pushed the truck hard enough to snap a trans case. Made a quick dash with some 1" square tube and aluminum panel I had laying around. Don't have anything besides oil pressure, ignition switch, headlights, and a battery disconnect. More importantly, cup holders were added. Made those out of the old driveshaft tubing in the scrap pile. Fits a magnetic koozie nicely. Mounted the cable trans and tcase shifters on the seat frame/console within easy reach. Paint is all rustoleum hammer finish, brushed on artistically. I put a hood on, but didn't have time to put fenders on so I left it untrimmed.

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Also whipped up a nice little storage tray out of some 16ga to keep the ice chest off of the fuel tank. My good friend let me use his shear and brake to knock this out moments before leaving for Clayton, Oklahoma.
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New wheelbase was a huge improvement on the trail. Steering angles could still be better (still have the steering ram limited from when it was on a toyota axle), but it was still way easier to navigate the trails. The suspension stays planted under throttle and felt stable all weekend. Coil overs have settled about 2 inches which actually is perfect. Suspension flexes well enough and donuts are still fun. I was able to make it up every obstacle that I had to winch on the previous year. Considering the rain and mud this year, I'm pretty pleased with it.

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Plans for now are to finish the body panels and add creature comforts, gauges, lighting, etc. Exhaust is fine but will eventually rework it into a single routed over the axle. Adding a doubler or some kind of gear reduction would be nice for crawling but the setup works fine for most trail riding. Just requires a little more speed than the rest of the group on the technical stuff.

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