I was wondering why more people are not using C4 headers (stock or aftermarket large tube) for single turbos?

I did this ugly mockup in paint, but from what I can tell by cutting the collector off and welding up a 2 1/2" log and a couple of bends, a vband on the bottom for the crossover and a T4 flange you would have a decent stainless single turbo header. (with good plug access from the top). Wastegate on the end of the log where it belongs...

Rather than the BBS/XS-POWER running the log in parallel with the exhaust ports, I say drop the log down so it's just over the motor mount. Ample plug clearance, ample downpipe/wastegate clearance.


-- Joe

 

Maybe on a ms/as shorty header. But how well would a cast iron c4 manifold weld w vbands a t4 flange n such?

 

84-91 C4 manifolds are all tubular stainless steel (and rust just like SLP headers). I think only the LT1 stock manifolds were cast. All aftermarket ones are tubular.

http://www.ebay.com/itm/84-corvette-factory-GM-exhaust-manifold-headrer-NICE-C4-DRIVERS-/370806763626?pt=Motors_Car_Truck_Parts_Accessories&hash=item5655ce306a&vxp=mtr

-- Joe

 

Yes, the C4 LT1 stock manifolds were cast, unfortunately my '96 is still wearing them. I never even considered the earlier C4 manifolds though, maybe because everyone might have assumed they were too scarce to get a hold of, but looking at them now they have a lot of potential. Looks like a pretty easy set to make twins with, that's for sure...

 

Twins would be super easy with them.

The only drawback to the stock ones is they are 1.5" primaries. I've read that on a turbo car you want to run a primary sized for a motor that is 2/3 the HP of your turbo combo, but 1.5" seems small.

Then again, the BBS header is 1.5"..

-- Joe

 

I would think the turbulence/flow of that would be terrible. You would basically have numbers 4&6 flowing straight down into the merge.

With the work it would take to make that you would be better off building a log from scratch. I would personally use minimum 14awg on a log like that. Or for the cost build it all out of schedule 10. I had major warping issues when I built a log setup with 16awg.

Jay

 

Definitely an alternative to build on but i am a huge fan of simple logs on simple builds. Can build a really solid log for dirt cheap in mild steel. 11 ga or similar, maybe even schedule 10, it would last forever

 

That's how the BBS/SSAC/XS-POWER and most logs are though. The #4 and #6 primary dump right into the log.

-- Joe

 

Yeah, I'm just wondering on the routing. As we discussed in PM, I'm not exactly impressed with the plug clearance with traditional logs. I'd rather have a configuration where the plug wires can be run from the top, with ample plug access and the log UNDER the plugs.

I've got a pair of these. I think I'm gonna cut one up and see what I end up with.

-- Joe

 

My car is kinda opposite. Good plug access from underneath car, no access from up top. Plug wires have to route around and under even with coil packs up top of fuel rails lol

Build the log to drop low and you'll have access

 

I'm actually still working on a set of twin cast manifolds, but they run up and parallel with the valve covers, and the plug wires run straight back and are held in place, and will be a breeze to replace from underneath, even with the downpipe(s) still bolted on. Even the valve covers come off no problem with them bolted in place. Here is an old pic when I was first mocking them up on an LG4 Camaro...

 

to add to this, 82 vette manifolds are very similar and they're 409 stainless also.

 

Just found a picture. Now THOSE are interesting! Like a tubular ram horn.

-- Joe

 

The c4 manifolds were my original inspiration for my sandersons. I think they are a good option but there are better options for the same or less money

 

That is exactly what they are

 

When C4 manifolds are bolted in, I wonder if their is enough room to get a 2 1/2" 90* bend to go forward on both sides..

-- Joe

 

joe ....ive been wondering the same thing.......

 

installed upside down or in the normal orientation? There is a setup floating around with them installed upside down and it works. installed the normal way, I would say yes, for sure with a tubular k-member. I am doing basically that with my block hugger headers

 

Got any pictures of your setup?

-- Joe

 

Replied to your PM then found this.

I forget what they hit in the normal position.( I think block/kmember issues.) They would have needed cut and pulled away from the block) At that point I said I'll just start from scratch. Thats when I mocked up and did a setup like prestons.

Upside down they worked great. I Kinda wish I keep this setup.

http://www.cecoatings.com/images/Car.../hotside304ss/

 

Upside down there is just barely enough room to cut the collectors up and mount a set of small twins up there (t3's ore similar sized). Right side up the engine mounts get in the way.

 

Any pic's of the Twin ontop of em? Id think they would be right over the valve covers.
Hitting the AC and Brake res.

 

a view of both:









there are a few more in this thread on page 11, with more to come

https://www.thirdgen.org/forums/powe...-z28-c-11.html

 

what headers are those? what happened to that oil pan?

 

Looking at those, and some pictures of smithy's setup that Chris provided, I think one could run a normal header on the driver's side,and either a C4 or block hugger on the passenger. Merge the crossover by the starter then run 2.5" under the motor mount.

Would make a nice tight clean fit. Then 90* straight up and run the T4 flange up top by the head, perhaps making a bracket to bolt to the head for extra strength.

 

just some Sanderson hod-rod headers, I modified the collectors to shorten them up

The oil pan is just cut in half... so I can take it in/out easily for mockup

 

Joe,

Thats what i did with one setup I built and sold. Used a SLP header nd chopped up y-pipe. Make a custom P.side turbo manifold.

 

I posted them here a _long_ time ago, should come up in a search. If not I can go digging...

 

this setup will not fit with the stock crossmember. I also suspect that once you get this in the car you'll realize that the main power feed from the battery to starter where it gets distributed to the rest of the car runs through there and would best be relocated, but yea, at that point it would work well...

 

Don't see why it wouldn't. My car is on the lift right now, and I can pass a 3" pipe under the motor mount. with clearance on all sides. Surely a 2 1/2" pipe would fit. The only tricky part is the radius on the 90*.

My power distribution is re-routed. I only have a single battery cable to the starter.

I wouldn't try running the crossover up front though, that makes no sense to me when you already have space between the pan and the k-member. Essentially, you make a "Y" just forward of the stater to grab the crossover and the passenger header, then snake under the motor mount and up to a T4 flange.


-- Joe

 

the tightest bend options I have found are the summit 120* bends, or if you want to spend the money a "donut" from a chassis shop can have a very tight radius

 

The C4 headers don't hug the block tight enough to be installed normal orientation, they go right into the k-member.

Flipped up, cutting the flanges off and welding T3 flanges on, you've got about 5.5" of room until the hood. What size turbo would that be?

-- Joe

 

You talking for twins now? If so why not just go this way.

 

I was actually still thinking single. I'm thinking of making one of those out of a passenger thirdgen manifold. I wonder if the crossover was up front so it merged at the T4 flange rather than into the log, wouldn't it be better?

Twins would just be too much work on my car. different intercooler, intake routing, etc.. Not interested

-- Joe

 

Those were from a Twin setup.

Ya should just make a setup with those vette manifolds and call it a day.

 

I might. I have another c4 header in the shop.

I started my car today and I still have a tick on the #8 primary, and the downpipe leaks at a vband. Hopefully have that fixed tomorrow.

I still want a cast manifold. I think I'll make a single out of a cast thirdgen manifold, and see how it comes out.

-- Joe

 

Like I'm setting up for this build? Third gen manifolds turned around to dump in front.

https://www.thirdgen.org/forums/powe...rbo-build.html

 

Yeah but I didn't consider using the drivers manifold on the passenger side. That's clever.

I was thinking of running the crossover under the oil pan, and then snake around the motor mount. I didn't think you could fit it under the front like you did. When you steer, the linkage doesn't whack the pipe?

-- Joe

 

I modified C4 manifolds for my turbo hot side.

 

No when I routed the crossover I turned the wheels lock to lock to assure it doesn't hit. I comes within about 1/2" of the castle nut on the pitman arm and a couple inches away from the idler arm.

 

What about something like this.

I wonder if a stock L98 manifold, modified in this fashion could support 700fwhp.

-- Joe

 

would be a cool simple set up. However the positioning would limit your turbo selection due to hood clearance.

 

I take it that the box around the manifold is supposed to represent the cylinder head and the dots the spark plugs?

"Support" the HP? Sure, no problem I'm sure. Honestly, it's probably better than some of the stuff that people used for more than that.

Will it work? I'm not sure, I don't think that you can make that bend between where you have the inlet for the crossover between it and the motor mount without cutting that area way short and getting in the way of the spark plug, and then I would think that you've cut too much of the manifold away and will be welding to much back, it will end up cracking quickly when you run some real power through it/get it hot.

Hood clearance shouldn't be a problem unless you're running something with a T6 housing, and even then I don't see why you couldn't rock it over/put the flange on the outside of the manifold. My bigger concern would probably be clearing the strut tower but that can always be notched and welded.

 

I started doing it. Whoever told me these manifolds were cast steel, not cast iron was not correct. These are a PITA to weld.

I welded two sides, preheated, slowed down the cool. Then I whacked it once with a 5lb mallet on the side of the T4 flange and it flew across the room.

My biggest problem making manifolds is overheating the header flange when welding, and causing epic warpage.

-- Joe

 

No offense, but it sounds like you might need to spend a bunch of time under the hood practicing before you tackle the next set. Also, patience goes a long way keeping stuff from warping, and air cool the part your working on frequently. I know your preheating so "cooling" sounds odd, but preheated and overheated are different.

I submerge real thin parts in water while Im welding them to prevent warping, like welding a head. It works really well

 

Huh, yea, I've heard of a few people claim that they're cast steel instead of cast iron, I doubt it, but I have seen a few sets welded (I don't remember how they claimed they did it).

If it was me I'd start with trying to use some stainless filler wire and work from there... typically some stainless will do cast iron well, if that still doesn't do it I'd try a different spot and see if its better. I've run into cast iron that welded great even with ER70S6 and then I hit a spot where it just wouldn't work and found that there was trash in the casting in that area that prevented anything from working right. I tried cutting it out, drilling... and finally gave up and just brazed that part.

 

Wow that was awhile ago.

I made a new set out of LT1 F-body manifolds. I used my stick welder, and a drum of sand. They came out great.

Rather than putting a box on the top and trying to force the flow out a hard 90, I used weld-el's so the manifold flows how it would naturally.

Enough casting existed to gasket match them to the felpro 1206 ports on my AFR 210 heads.


-- Joe

 

LOL, I didn't even notice the date when i posted that, was just catching up/cleaning up old stuff...

AAMOF, I know I commented in the other thread with you messing with the LT1 manifolds a couple of months ago :-P

 

Yep.. I took that picture about a month ago. I have not been inside the garage since. Hopefully I'll have some time this summer to finish putting the car together. Maybe actually drive it once or twice in the fall. I doubt it though.

-- Joe

 

yea, I'm kind of in the same boat, I tore mine down probably over a month ago, and have only had time to touch it intermitttently since, I don't think I've actually touched the car in 2 weeks now (though I have messed with some parts in the basement...).

I really still hope to have it running again before the end of the month, but I guess I also have to figure out how to make some changes in the MS before I fire it (MUCH bigger injectors, I've gotten 3 different answers about scaling the tune for it in the MS forums/groups which has me pretty annoyed).