Builds Joel's multipurpose 40 on 41s (1 Viewer)

[frijolee]

It looks like the vette alternator bracket is only $85 or so new so I'm not out much if I screw one up. Here's my first cut (ahem) at a piecut.

The intent would be to keep the relative position of the two mount points constant. However, now as I think about it some more, it might make more sense to leave the lower mount fully attached and just roll the top mount inward via a pie cut. That would help keep the alternator belt aligned. Clearance would be best if I could roll the bottom mount inward, but I think that is likely to get into the space for the power steering pump pretty quickly. Thoughts?

Assuming I do screw with the top mount position on this bracket it intuitively wants to get a bit shorter, but I could still run the slightly smaller form factor GTO alternator as I still have one of those lying around. Anyone have a favorite alternator form factor?

-Joel

 

[frijolee]

About this point a good friend jumped in and kicked my ass with his logic:

You want my .02?

You have a packaging problem mixed with an engineer.

Offroad s#!t gets the hell kicked out of it. Bitchin custom this and that gets borked then you are stuck, SOL, side of the road.

I really think you should make every effort to use factory, or similar parts. Strength at minimal cost so you can have spares, not break the bank, etc. Unless all other options fail.

My experience with these bracket systems makes me lobe factory stuff more and more, or the cast holly stuff.

Use the alternator that fits. That will likely be fbody. The truck alternators are more bitchin, but huge in comparison.

Save the 4 grand for the vintage air setup, and buy a stack of factory parts to praxtice mock up.

The chassis has been build with a no compromise suspension, play to that strength. Go factory motor that you can swap out in a weekend when the inevitable happens. Fit a tank under the rear seat, and put cushions on it.​

Ah the 65imp nugget of truth. You kick my ass and yet I still have much love for ya' amigo. That's a pretty simple way of looking at why stock is good, but you're probably right. I think I really need to see what the shocks do with the chassis fully twisted up before I assume I shouldn't be moving those instead. There isn't factory high mount AC option I'm aware of so Holley will have to do if I want AC and still want to keep it simple. The good news is that I think that could tuck under one of the rails since I'm about even with the top of my throttle body opening.

Note: in the above, I had started to play with whether I could cut this down as well and while I could, I think you're correct it's best to avoid that unless required.

Alternator side, there are only two factory high mount alternator's I'm aware of: Vette and Truck. Since I already have the vette I might as well try it, even if that means cutting, before I assume I need to do something crazier and go truck. I'm not certain the truck's power steering position will work for me either.

 

[SuperBuickGuy]

Holley also sells stand-alone serpentine systems for the LS motor that don't use billet aluminum and chrome.... save you a bunch of money. Last I checked they were about $1200 for the entire set up (with alt, and ps pump). I also know of other, more fly-by-night outfits that sell bits and pieces to craft your own system.... Speedway motors is where I'd start with that search.

as for daisy chaining the fuel tanks... you can make it work, but why are you against switching between the tanks with a traditional switch? Use a holley pickup sock in each, a 87 GM Truck fuel tank switch (designed for efi and 2 tanks) - or a diesel from 82 up - and run two separate tanks. That way should you hole one, you'll still get home. The biggest issue with 2 tanks and EFI is the return (unless you use the GM tank switch). The reason for the hydramat (the sock) is twofold - 1) it's a filter, and 2) they work amazingly well at getting the last drop out... oh yeah, and they also work in lieu of a surge tank

or you can run your tanks linearly and use your second tank as a surge tank... there you'd put a one-way valve between the fill up tank and the 2nd tank. Problem is it'd take for'effing'ever to fill both to max capacity.

As for serpentine set ups, the biggest deal is always tension. Getting the belts in line is pretty easy, but then you need to find a way to tension the belts. With a spring-loaded tensioner, it's fairly easy, but if you use a spreader (like many of the 4k systems use), they tend to throw belts when the bearings start to wear.... don't ask me how I know this.

 

[frijolee]

Super Buick,

Thanks for the tips... I'll have to look into the fuel tank switch as that's an approach I hadn't considered.

I like the Holley setup a lot. Is this the one you're referring to?

In my mind the best thing is that you can get each half (AC and alternator) individually. My first stop will be to see if I can make the vette alternator work. If I can then designing around the Holley for the AC half makes sense. One good bit of news. It looks like I can drop the engine a bit which should greatly help the ability to package both high mounts I'm investigating.

This pic is from last night (when I was checking this out)

Looks like I can go about 3/4" before I have to rework the skid plate frame (Still want a little clearance for skid plate to bend and deflect before it loads up the pan... The bad news is that because this sat through spring while I was traveling, I have some surface rust to deal with.


Question for the forum then:

What's are you all's favorite paint / rust conversion / rust inhibitors? I'm not opposed to the approach of hit it with some cheap stuff then sand off and redo, but I'd love to get a few more bars and structure added before I do. We're at least back in SoCal's dry season so I'm kinda tempted to say screw it, if I have to deal with some surface rust just about everywhere, dealing with slightly heavier surface rust isn't a big deal.

 

[SuperBuickGuy]

you know eastwood has a rust inhibiting spray (comes out of a squirt bottle) that's for bare metal to protect it while you build (there are others as well, but that's the first that pops to mind, I think WD40 makes something similar as well) - from what I understand (keep in mind, I'm in Seattle and paint rusts here) it works really well in dry climates by keeping the dew off and not creating havoc later when you paint it. It's what they used on James Hetfield's (Metallica) bare steel cars to keep them from rusting but still allow him to drive the wheels off. Otherwise, you can use rust converter to create a shell, or simply spray it down with phosphoric acid (keep it off the aluminum) to create a good barrier.

glad to help

 

[frijolee]

New topic, exhaust planning... Again looking for a forum sounding board/sanity check.

Earlier I mentioned that I want to run my exhaust down the boat sides on either side of the frame rails. There’s not a great deal of space but I’m optimistic I can wedge something in there. Been playing with the idea of making some custom triangular shapes but that’s just an option.

The first trick will be how to get headers of any kind of a decent length to package on the engine side of the firewall. I can't see the bundle of the tubes running through the triangular hole just under the footwell on each side so it’s going to take some creative routing. The good news is that my stance is so wide that I do have quite a bit of space at the sides of the motor and that opens up options. Best possible conceptual run I've found was done on the 2013 Miller Motorsports KOH Rig.

Super simple, super clean. Credit to the guys at Liquid Iron Industries who made this on behalf of Erik Miller (epic build thread here if anyone is curious): 2013 Miller Motorsports Ultra4 Car - Pirate4x4.Com : 4x4 and Off-Road Forum

I'd basically plan to route my headers as a mirror of what Erik did (running up and forward instead of up and back). Miller's car was about 18" primaries. I'd love to get mine north of 30" if I can. Instead of the merges exiting pointing downward, I’ll also make mine turn horizontal again to gain some length (merges point toward firewall).

I’ve also been reading about merge collectors. I ran across some folks who should know (Joe Sherman of Engine Master’s fame was one) who claim they don’t do much except possibly down low. MERGE COLLECTORS,WHEN TO USE,HOW BIG A CHOKE AND WHY • Speed Talk But that’s the thing, I care a great deal about torque down low for this rig so I’m still planning around merge collectors.

Note: my last set of merges I bought from Burn Stainless who spec’ed them for my RX7. They were (are) rad but budget constraints rule Burns out this time. Instead I’m going to spec my own and trust that they’re close enough… From lots of history on here (with a dash of David Vizard theory thrown in), I pretty much think that 1 ¾ primaries with a 2.5” dual exhaust is about optimized for a stock displacement LS1. That said, you can just as easily do 1 7/8” and 3” duals not leave a lot on the table and still have room to grow. That’s my plan, so I basically just need to spec the merges and components to make it happen.

I’m looking at:
• 1 7/8 primaries (a touch oversize for an LS1, but I could easily see this growing down the line
• 15 deg merge angle
• 2.5” choke diameter (more on that in a second)
• 10 deg transition
• Just enough length running straight for 02 bungs.

12 deg merges have a reputation for making the most power but they’re just too long and 15 degree merges are notably shorter but not that far behind. The hardest bit to spec out was the choke point diameter. I didn’t have a great grasp of what the choke point does (still don’t fully get it, but the most helpful description I ran across was the following from the Speedtalk thread linked earlier:

The principle that is at work in a merged collector is this. The smaller the choke the longer it takes for atmospheric pressure to equalize into the back door of a given engine. It protects your power curve the same way as shorter cam timing and longer primary tubes. Just slipping a collector on with a smaller choke will usually show more power at the bottom of the curve. (which Joe points out)..
The secret is that you can now shorten your header which is how you can make more power upstairs.

Header length is always relative to rpm band but also the size of the choke. Most headers have to be long because the collectors are so large. The longer tubes keep the reflected wave "back" at the lowest point on the power band that the engine has to pull from. Change the collector choke and shorten the tubes and you will see the power. If you can't shorten the tubes, do not blame the collector, and if you need shorter headers, call me...

I am using Joe Sherman's example as what will happen just installing on a existing header. If you can not shorten your header or get one shorter for your application, Joe is absolutely correct, they are expensive and are not a solution in themselves.

Calvin Elston
Elston Exhaust Inc.
Matthews, NC 28104
704-443-8088
Web: www.elstonheaders.com
Blog: www.exhausting101.com

I also ran across a decent cheat sheet on this particular topic.
www.coneeng.com/pdf/Area_Calculation_Table.pdf

Screen cap cribbed here:

Short story: picked 2.5” choke based upon the chart and goal of focusing on low end torque. If anyone has better resources please chime in. Note, one cool thing at the www.coneeng.com site I ran across is a DIY merge collector of sorts that still lets you weld it around 100%.

Slip On Collector, Conical Merge Collector, Slip On Collectors

I never liked that there’s no way to 100% seal my slip on collectors on the RX7.

So that leaves the rest of the exhaust. I’ll run a V-band off the header and then duck under the floorboard into the boat side.

I might be able to snake an H-pipe across but I'm not sure. I do want to try to keep this rig relatively quiet but that may be a challenge given the lack of internal insulation. That basically means I want as much sound deadening material in the muffler can as possible. Even using a triangular shape I don’t have a huge space to use but I can make the muffler pretty long. It also needs to be held relatively rigid in space because clearances aren’t going to be much. So that brings me to the next question. How flexible are flex pipes? I used one on my jeep but that’s my entire experience with the things. I think I may need one on each side before I run under the firewall, which eats up space I’d rather use for header primaries. I assume the interlocking style flows better, but I’m guessing the double braid is actually more flexible as I would think it can do a bit of in/out motion (Chinese finger trap style) Anyone know for sure?

That brings me around to considering engine motion and clearances similar to the train of thought on AC and accessories. I could run this solid mounted (or nearly solid). There’s nothing I can do about thermal growth but does anyone have opinions on whether I could get away without a flex pipe?

What style of hanger would you use in extremely close quarters?

I’m planning to dump this in front of the rear and point it slightly downward. Am I dumb for even thinking that an exhausts that exits under the vehicle can be tamed enough to be livable?

If that’s too boomy I may have to figure out how to snake it over the rear axle which isn’t trivial but doesn’t look impossible either. I just need to duck to the inside of the frame rails. The upside of taking the exhaust all the way back is that I could work out a Porsche style crossover exhaust.

Something like this internally, but with perf core and a case around the bulk. This is about as close to an X-pipe as I think I'll be able to pull off.

That might let me just run simple glasspacks or similar down the side and save the effort with the crazy triangular mufflers.

[/quote]

 

[Flipper1938]

Fyi...running the headers up and then back down increases underhood temps a bunch. More tubing in the engine compartment to exchange heat AND it blocks air leaving the engine compartment. .....at least it did on my 48 Chevy hot rod.

 

[frijolee]

Flipper, good thought. Do you have any pics handy to compare that setup to what I'm envisioning?

I was looking at this earlier today and I'm not really looking to cook my AC compressor or alternator so I hear what you're saying. At the same time long tube headers and tuned length pulse reflections make such a huge difference in performance I really want to try. I just don't see any way I'm getting a bundle of 4 primaries (even 1 3/4) to snake under the pedals and floorboards.

As mentioned, my wide stance means I can go out quite a ways which should help with heat management.

 

[Flipper1938]

Flipper, good thought. Do you have any pics handy to compare that setup to what I'm envisioning?

I was looking at this earlier today and I'm not really looking to cook my AC compressor or alternator so I hear what you're saying. At the same time long tube headers and tuned length pulse reflections make such a huge difference in performance I really want to try. I just don't see any way I'm getting a bundle of 4 primaries (even 1 3/4) to snake under the pedals and floorboards.

As mentioned, my wide stance means I can go out quite a ways which should help with heat management.

The truck runs great and sounds even better, but damn it gets hot when you stick your foot in it!

 

[Mace]

Also keep in mind that if you run the exhaust under the footwells it has the potential of melting your shoes...

 

[frijolee]

Also keep in mind that if you run the exhaust under the footwells it has the potential of melting your shoes...

Any alternate suggestions? Here's my though process on that:

-I could do a dump straight out the side of the engine bay (sides or heck, even through the hood) but muffling and header length both become problematic and the potential to breathe exhaust goes way up. Still it's by far the easiest run to make happen. It's also one more thing for a cop to look at me sideways for and I kinda think I may have enough of those already.
-I could do side pipes but now they're in harms way for the rocks (yes could armor but it's more work). Risk of burning one's self when climbing into a high cab is real as well.
-There's no space to get past front driveshaft and transfer case on the driver side. That means running on the inside of the frame rails is problem unless I can run down the passenger side only. I don't see a good way to do a crossover from driver to passenger to run a single out the back. If I do go single it'd need to be min 3.5" and has to dump under the rig since that's not getting past the rear axle.

I've kinda stared at this for a while and I think I only really have three choices
-Option 1) Engine bay dump
-Option 2a) Under floorboards (through that tiny triangle) glasspacks then dumping before rear axle.
-Option 2b) Under floorboards, routed to the back with a cross-over style muffler (likely limits me to 2.5" duals)

For under floorboards, heat shields and insulation are all I can do.

Like I said, I'd love some alternate suggestions, but looking at it in person. It's just not easy.

Oh, bonus note on 2b) above. I went digging on some of the Porsche forums for what they use as mufflers. Turns out the dual in, dual out Magnaflows with the Tru-X perforated core are really popular. Interesting since the two sides kind of fire at one another but seems to work well regardless.

 

[Flipper1938]

Ls3 manifolds are actually pretty good performance wise. Long tube, high dollar headers only pick up a few horsepower on a camaro (8-10?)....try looking at 2 drivers side manifolds (pass side dumping forward) and run single exhaust down the drivers side. That would leave a big hole on the passenger side to let hot air out.

 

[Flipper1938]

GM Performance Parts LS1 Engine Header and Manifold Test - Car Craft Magazine

 

[frijolee]

Flipper,

I'll have to look into the LS3s specifically but manifolds and shorties aren't the right length to take advantage of reflected pulse wave tuning. Long tubes should be a great deal more valuable than just a few horsepower if done right. [BTW hadn't seen your link when I wrote most of this, see follow on post for more].

Excuse me while I tangent, but this is kind of a topic I geek out about (as in A LOT). I've spend a bunch of past effort on optimizing breathing tracts and maybe this will help someone...

Starting from the most basic (much credit to David Vizard's "How to Build Horsepower" which strongly influenced my thinking in this regard):

An engine is an air pump which means the entire intake/exhaust tract is interrelated so the biggest gains come from doing the one weakest link last (hence guys claiming a K&N filter can make 30hp). There are two events going on in headers: actual particle flow and the shock wave from the exhaust valve cracking open with residual explosive pressure behind it which then travels at the speed of sound like any shock wave. Air moves via pressure deltas right? Vizard measured the pressure delta of a moving piston sucking air past a variety of heads and found it's typically only about 1-2 psi for most heads since the valve opening are relatively large. Better heads have less restriction and flow better so agressive street heads are in the 1 psi kinda range and race car applications have heads with such little restriction they draw with only about 0.5 psi.

Now looking at the second aspect, the shock wave I mentioned. Shock waves bounce when they high the open end of a tube (typically the merge in this case) and reflect back up stream as negative pressure wave. If you time it right (meaning the start of valve overlap) this pulse wave is actually what begins pulling in the intake air as well as evacuating the chamber. Vizard's testing claimed this reflected pulse wav pulls more like 6-7 psi.

Comparative, this means that shock wave is sucking 5x harder than the piston without help (IE shorties).

Let's say you have a 10:1 compression engine. The motion of the piston can't easily clear the last bit of exhaust in the combustion chamber (there are some second order effects of particulate momentum, but it's not where nearly as effective for scavenging as the shock wave). Given the combustion chamber is the 1 in a 10:1 engine, scavenging means you can get all 11 volumetric units of air exchanged instead of only the 10 units of volume the motion of the piston get you. Effectively you should be able to see more like +10% hp difference for long tube vs. manifolds on any given engine (40 hp in a 400 hp v8).

My personal experience backs this up. I made 65 more rwhp (430 vs. 365 IIRC) vs. a nearly identical friend's car. Both were v8 powered rx7s, same driveline, mostly the same mods, with the only only major differences being my car having long tube headers and ported stock heads. Then I updated my intake tract (still on a stock ls6 intake manifold, mind you) and made 462 rwhp. That's excellent for a stock 5.7L v8 with a mild cam and ported stock parts.

Ever since then I've been hooked on this stuff. The RX7 now has a 429 ci LS2 stroker. These were the second gen long tube headers I built for it when I did the big motor.

People sometime brag about equal length headers. I tend to think equal isn't nearly as important as length since it's very possible to have something equally the wrong length. For any given camshaft the perfect timing only works out at one RPM but it won't matter if one cylinder gets it's max effect at a slightly different RPM than the cylinder next to it. For an LS with a 230 ish duration cam that's about 30" primaries. If you wanted this to come into play at more like 5000 rpm you'd need 42" primaries. You can also play with smaller steps at variable frequencies (F1 does this extensively).

That's all to say, my geeky sensibilities are going to suffer mightily if I have to "compromise" for packaging reasons and for now my heart's pretty well set on long tubes (even if I have to build them).

Joel

 

[frijolee]

PS, many thanks for the link (just saw that after posting the above).

It's damn impressive the LS3 manifolds are that good. It does say that the F-body manifolds in the comparison between my friends car and mine weren't nearly as good. I do wonder if in using a stock engine (stock cam) they weren't taking advantage of valve overlap to get the full benefit of the long tubes. Clearly something's going on as they're making 400 engine hp on a stock LS, when I made 462 wheel horsepower (~550 engine?) on stock ported parts with a medium cam and headers.

It was also interesting that the article referenced 40" headers for more low/mid range torque. Not that different from what my prior math/research found.

Really what this will come down to, is that if I can't get at least 28" or so of length out of the headers I might have to give up on the idea at which point the LS3's become a pretty viable option. Thanks for the links and commentary!

-Joel

 

[peteinjp]

I know absolutely nothing about the stuff so forgive me if I say something totally stupid but I wonder if you could make me a room for all your Engine stuff by eliminating the mechanical water pump.

At any rate I find is going to build totally fascinating. Keep us posted!



Pete

 

[Mace]

Any alternate suggestions? Here's my though process on that:

-I could do a dump straight out the side of the engine bay (sides or heck, even through the hood) but muffling and header length both become problematic and the potential to breathe exhaust goes way up. Still it's by far the easiest run to make happen. It's also one more thing for a cop to look at me sideways for and I kinda think I may have enough of those already.
-I could do side pipes but now they're in harms way for the rocks (yes could armor but it's more work). Risk of burning one's self when climbing into a high cab is real as well.
-There's no space to get past front driveshaft and transfer case on the driver side. That means running on the inside of the frame rails is problem unless I can run down the passenger side only. I don't see a good way to do a crossover from driver to passenger to run a single out the back. If I do go single it'd need to be min 3.5" and has to dump under the rig since that's not getting past the rear axle.

I've kinda stared at this for a while and I think I only really have three choices
-Option 1) Engine bay dump
-Option 2a) Under floorboards (through that tiny triangle) glasspacks then dumping before rear axle.
-Option 2b) Under floorboards, routed to the back with a cross-over style muffler (likely limits me to 2.5" duals)

For under floorboards, heat shields and insulation are all I can do.

Like I said, I'd love some alternate suggestions, but looking at it in person. It's just not easy.

Oh, bonus note on 2b) above. I went digging on some of the Porsche forums for what they use as mufflers. Turns out the dual in, dual out Magnaflows with the Tru-X perforated core are really popular. Interesting since the two sides kind of fire at one another but seems to work well regardless.

Locating the exhaust in the boatsides may just be your only route. So heat shields will be very important. As will not enclosing the boatsides entirely so that radiant heat can escape. The caveat is depending on what type of wheeling you do, you really want to make sure you can clean out any debris that can get trapped (mud or brush). I prefer multi layer shields with a layer of fiberglass (or similar) sandwiched in between some steel.

How many HP are you looking at? (I may have missed it earlier)

 

[frijolee]

Agree on the heat shields. I don't see much downside to having the boat sides nearly 100% open. CA is mostly dry wheeling and brush shouldn't be too terrible to clean out. You kinda have to be into a rock at the exact right angle to not be sliding on the rocker or frame rail anyways. I will made a mid skid for the bottom flat.

Horsepower? Stock displacement I should be able get 500 engine hp out of it, but that likely takes a cam to do so. No idea what driveline loses will be like in a rig like this (whp). I've debated swapping engines with my RX7 (429 ci LS2 stroker) but for now I'm sticking with the engines in their respective homes.

RX7 for ref...

 

[SuperBuickGuy]

after my C3 Corvette with side pipes - I'll never run exhaust anywhere but outside the rails (if I can help it).

Just a rule of thumb - every 90 degree bend has the same amount of back pressure as 10 linear feet of pipe. When you're looking for 30" primary lengths - remember you're getting good back pressure just from the turns required to get the exhaust out from under the engine.

Temps can be an issue, but are really easy to address if you build your headers out of stainless and wrap them. In my system, it's 450* before it was wrapped, now I can hold the header with my hand while it's running. One thing I did have to do, I put fire wrap on top of the muffler - that space is pretty tight so reducing top temps would be a good idea. I also control the heat with ceramic Lizard Skin top and bottom. It's good enough that when the exhaust hanger caught on fire (because of swapped plug wires), that it didn't damage anything including the gas tank that was immediately above it.

With the blanket on top of the muffler, I haven't melted a shoe yet and the pipes are bare under (and I run a catalytic converter on each side so I don't get migraines from exhaust fumes)... that's under the floorboard at my feet as well.

My exhaust is boxed through the body mount and protected by the sliders.

 

[frijolee]

I'm thinking seriously about running 2.5" piping (instead of the dual 3" version I assumed I'd run). It packages notably easier, both getting under the firewall (aforementioned triangles) and getting over the rear axle, assuming I take the exhaust all the way to the back... and I'm leaning that way. Despite the simplicity of dumping in front of the rear axle, I want this to be relatively quiet and going out the back helps that a great deal. The one time I drove my XJ with an under car dump I ended up putting in earplugs halfway through the drive.

If I want to tuck a cross over muffler under the rear floorboards (mounted laterally behind the rear end), I think I'm looking at two choices:

Magnaflow 12468

It's already 2.5" piping, it tucks in a little better. 18" case width is a lot happier (only have 30.5" inside rails back there). I'll need to raise the rear deck something like 2" and it can mount with the oval at an angle. I do worry that the muffler will be choking flow and I question what kind of impact having the two inputs fire at one another would make. I really liked David Vizard's approach of running a larger muffler core vs. the surrounding piping (IE 3" core with 2.5" pipes could be nice) which has me looking at the next muffler, but packaging becomes much much harder.


Magnaflow 12599

The problem here is that the 22" case width is just too wide so I'd end up doing surgery to cut down the body by an inch on each side just to get it to package side to side, then more cutting to taper from 2.5 to 3" pipes, then raise the rear deck something like 5-6" since the oval needs to mount just about straight up and down. This is a big muffler which might be good for sound suppression despite the larger piping.

On net, I think I should probably do the simple/smaller version, maybe try dyno'ing it with and without the muffler if I get curious...