COE A 42 GMC Bike Hauler thread

Been awhile. Will be finished with the trailer by the end of the year .
I did finish the interior of my model a and the sun visor. Done lots of beadrolling over the summer , got to pay the bills . Won’t bother you till I get back on the COE .

 

All the metal looks great,,, won't it be hot?

would material glued on calm down the Texas Heat.?

 

It’s not hot , every thing has lots of insulation behind it and the glass is so short I don’t get much direct sunlight .

 

That is so cool...so much better than the flowered***** carpet I had on the doors of my first hotrod lol

 

Ok , as soon as it warms up a little and I can paint the rest of the wood work in the Airstream I will be done with 99% of it and will be back on the COE . Should be April and back full time on the COE , although it will take me a week to figure out where I left off . All the time away has put a lot of thoughts in my mind of the design . Problem of being awake at 4am . Will see .
Just a small amount of the work I’ve been doing , not a wood worker . Blue

 

As usual very nice work!

 

I got wood just looking at it!

 

Thanks guys , don’t know why they doubled up on the photos . Blue

 

I think it is beautiful, except that you need a pizza oven....LOL

 

On a diet .

 

Been working on my Tudor . Honing up my metal skills . A little panel adjustment left .
Blue

 

Impressive!!!!!!!

 

So clean, so nice and so so cool!

 

So I’m back on the COE . Started working on the exhaust and had to fit up sheet metal first . It I’d SS and will get polished .

 

Show more of triple size pipes for shaping please

 

Only ones I have on my computer, see if I can get some tomorrow.

 

Very cool, very nice work. Wish I had 1/2 your skills. Q" how much horses you got in the COE? What size stacks ? I just purchased 4" stacks for my 39, & now I'm told that I can't run 4" exhaust on a stock 350. Said I will louse power. Got to have some back pressure? So I 'm planning on running 2.5" inside the 4"? Got to have the bigger stacks, so cool looking...

 

502 hp , 4” stacks . If you run a 2.25 or a 2.5 exhaust off you motor for a foot or whatever you can enlarge to 4” with no problem the exhaust will have the back pressure of the smallest pipe . On a 350 a 2.25 will deliver better torque and the 2.5 better hp , of coarse I’m talking duels . Good luck . All info from magnaflow you do not have to run the 2.5 in the 4” you have already made your backpreasure .

 

On my exhaust I’m using 3” from headers to mufflers 4’ feet towards the back . Making a u turn with 3” back toward the stacks with 3” glass packs as resonators then going up to 4” stacks . Was told this would be find for my hp and torque but I could use 2.5 or 2.27 under the truck and increase the torque. Hopping I don’t have a problem , but if I do I will install a 2.5” muffler . Motor rated at508 hp at 5200 rpm and 580 ft-lbs at3600 rpm .

 

Looking good Blue! General information; have a 351 with tri-y headers into 2 1/2" exhaust into Magnaflow mufflers, in and out same end (facing forward), I used 36 Ford torque tubes for stacks. Even though I had drilled 1/4" holes in the bottom of the 90 at the stack to release moisture (condensation) from pipe, when I started it up it would blow out black soot when cold. I solved that by installing electric cutouts, open when starting and closed when warmed up. Something else to think about.

 

I'm not sure what the HP & torque is on a stock 1989 Corvette motor? I was told that 89 was a bad year, Corvette cut the motors back for smog. Good low end torque but falls on it's face at higher speeds. Corvette had 280 or so rear end gears & it helps to change to 320s or so. I have 355 gears I was told that that would help.
Motor is still under the cab, but moved back at the back of the cab. 2.25" pipe out the manifold out & down, right after it curves back, is the muffler. I have not picked mufflers yet but there is only room for 14" mufflers before the pipe starts to curved around behind the bottom step. I don't have a foot or so before or after the muffler.

 

When it comes to back pressure, have you ever noticed that "run what ya brung" drag cars often don't have any pipes behind the headers? Blue is right, once you've gotten past the header collector, bigger is better! Putting a 2 1/2" pipe inside a 4" stack is a waste of time and materials

 

When I use to drag race , you wanted hp and high rpms . No back pressure, just get rid of the exhaust. Had a mouse motor that we were getting about 450+ hp out of but needed the rpms to get off the line because the high hp made the torque. Any thing under 3500 rpm it would fall on its face . Old days , got tired of building 15,000 dollar engines three or four times a season . I really couldn’t afford it now days .

 

great to see your back on the COE, I look forward to seeing more

 

I was thinking the same when I decided on 4" stacks, bigger is better. I don't want to sound like I know what I am talking about, I spoke with a rep. from one of the muffler manufactures. He said you need much much more horse power than a stock v8 to run 4" exhaust.
Now let me add that I'm building a hi way cruiser / trailer hauler, not a race truck. I don't know if that makes any difference? This is all over my head, I'm learning as I go, building this truck. I will be looking a-lot more into it, as I have not picked mufflers yet. I needed the stacks & elbow's to get around the steps to determine how much room would be left for mufflers. There are way to many mufflers out there to figure that one out quick. Since mine will be so short, & right under my seats, & I want as little cab noise as possible.

 

It sounds like you were told the same as I was. Since you have over 4' of smaller 3" pipe before the muffler & more after the muffler before you stepped up to 4" would passably be OK. You also have a-lot more horse power than I have, making 3" pipe off the collectors/headers possibly OK? From what your saying, you may need to reduce the size of the muffler flow to create a more little back pressure? is that right?? Be leave me this is all over my head & I'm trying to get it all understood..

 

It’s all about volume. You will never have more volume/ pressure than your smallest pipe . Think about when you have larger exhaust tips put on a pipe . Going from a 2 1/2 to 4 is like going from it to end of the 2 1/2 to open air , you are just directing the hot gas where you want it to go .

 

That all makes seance to me? But going back to what you said earlier about possibility wanting to reduce your muffler down to 2.5 to increase torque. Is it because your motor was originally designed for 2.5 exhaust to get peak torque performance, but changing to headers brought you up to 3" off the heads, so you may need to reduce it back down some were, back to 2.5 to get possible torque lost back ? I guess that is what is confusing me? Why would there ever be a reason to reduce the flow if quicker exhaust is better performance?? I think, me not understanding low-end torque/high-end torque verses horsepower on a stock highway driver?

 

I have the feeling there was a misunderstanding between you and the rep. I think the truth here is, you don't "need" 4" exhaust until you have much more horsepower but having 4" exhaust is not going to be detrimental to your HP output.
Another substantial part of the equation is, "at what RPM do you want your max torque." For a diesel working truck, best efficiency is max torque at cruising speed and I'm****uming a gasser is the same, or very close. For my Detroit diesel, max torque is 1900 RPM, so I need rear axle gears that will give me 1900 RPM at 70 (6th gear) and 55 mph. (5th gear) the lower gears just determine how soon I get to cruising speed.
BTW my redline is 2800, which would have me over 100mph at redline, enough for this old man.

 

For a 350 21/2 is great unless your drag racing . Most header collectors are 3” but the 3 to 21/2 come for them . You need a 3 “ collector to get 4 pipes into . A 430 hp LS 3 has 21/2 exhaust manifolds exit . The reason it’s smaller is a street drive car is driven at all different rpm . Where a drag car is wide open . Now let’s talk about torque converts or let’s don’t.