bsmuwk Posted March 1, 2012 Share Posted March 1, 2012 Gents, Have some questions for you. I have the exhaust/intake manifolds off of my car right now. I cleaned out the exhaust manifold and it's minty fresh right now. As for the intake manifold - I'm in the process of dewebbing it right now. I'm blocking off the pop off valve with a 1" pipe plug and am going to be grinding down useless bumps and I've already made a plate to block the EGR. I want a bare bones manifold here folks - what's absolutely necessary to keep on this manifold and what can I just get rid of? The car isn't going to be driven in the winter, so what can I get rid of in terms of cold start equipment? Does anybody run a 3" downpipe on their stock turbos? I'd love to have some pictures of those set ups for inspiration. I have all the 3" piping in the world and I'd love to fab one up. Quote Link to comment Share on other sites More sharing options...
calvin280zxt Posted March 1, 2012 Share Posted March 1, 2012 I think the air while idleing goes thru the cold start crapp. I tried pluging it the other day to find a vac leak Quote Link to comment Share on other sites More sharing options...
LanceVance Posted March 1, 2012 Share Posted March 1, 2012 Check out BRAAP's EFI guide for information regarding what can be removed from the stock manifold. Quote Link to comment Share on other sites More sharing options...
KnightoftheRound Posted March 2, 2012 Share Posted March 2, 2012 I didn't have any cold start or emissions crap left on my L28ET swapped 82 slicktop. Didn't have any problems in winter. Sometimes if its really cold you have to keep the idle up so it won't stall by depressing the gas pedal a little, but its only for like 10-15 seconds. Quote Link to comment Share on other sites More sharing options...
FricFrac Posted March 2, 2012 Share Posted March 2, 2012 Gents, Have some questions for you. I have the exhaust/intake manifolds off of my car right now. I cleaned out the exhaust manifold and it's minty fresh right now. As for the intake manifold - I'm in the process of dewebbing it right now. I'm blocking off the pop off valve with a 1" pipe plug and am going to be grinding down useless bumps and I've already made a plate to block the EGR. I want a bare bones manifold here folks - what's absolutely necessary to keep on this manifold and what can I just get rid of? The car isn't going to be driven in the winter, so what can I get rid of in terms of cold start equipment? Does anybody run a 3" downpipe on their stock turbos? I'd love to have some pictures of those set ups for inspiration. I have all the 3" piping in the world and I'd love to fab one up. Instead of making it look good while you've got it off make it work better. The stock runners are a major restriction - almost half of the area of the intake valve. Port them out and at least get rid of the casting ridges. A 1" 60 grit flapper wheel on a die grinder works well - even better if you have an extension. I recomend using some heat barrier on the heat shield if you have all that off. DEI makes a nice heat barrier blanket with mylar on one side to help reflect the heat back that you can put on the heat shield. A 3" downpipe isn't going to mate up to the stock turbo - the outlet is less than 2.5" - you'll have to taper/flare/grind, etc to get up to 3" smoothly Quote Link to comment Share on other sites More sharing options...
bsmuwk Posted March 2, 2012 Author Share Posted March 2, 2012 Instead of making it look good while you've got it off make it work better. The stock runners are a major restriction - almost half of the area of the intake valve. Port them out and at least get rid of the casting ridges. A 1" 60 grit flapper wheel on a die grinder works well - even better if you have an extension. I recomend using some heat barrier on the heat shield if you have all that off. DEI makes a nice heat barrier blanket with mylar on one side to help reflect the heat back that you can put on the heat shield. A 3" downpipe isn't going to mate up to the stock turbo - the outlet is less than 2.5" - you'll have to taper/flare/grind, etc to get up to 3" smoothly Oh I've been porting out the runners for a few hours last night and making sure everything was as smooth as possible. I'm going to be wrapping the exhaust manifold and turbo with heat wrap so the intake manifold won't be soaking up so much heat. I figure it would do a better job than those flimsy metal shields. Besides, the car's going to be in motion more than it's going to be sitting anyway. I've been looking at my turbo and there's definitely more work than I hoped was involved in mating up a 3" downpipe. My turbo has no shaft play whatsoever, but I need to take steps ahead to get some power out of this car. Looks like I'm going to have to spring for different turbo and just shelf this little T3 for a while. Quote Link to comment Share on other sites More sharing options...
ZUL8TR Posted March 2, 2012 Share Posted March 2, 2012 3" downpipe mating to a T3/4 turbo shown from top and bottom Simple plate to block off the EGR Quote Link to comment Share on other sites More sharing options...
FricFrac Posted March 3, 2012 Share Posted March 3, 2012 Oh I've been porting out the runners for a few hours last night and making sure everything was as smooth as possible. I'm going to be wrapping the exhaust manifold and turbo with heat wrap so the intake manifold won't be soaking up so much heat. I figure it would do a better job than those flimsy metal shields. Besides, the car's going to be in motion more than it's going to be sitting anyway. I've been looking at my turbo and there's definitely more work than I hoped was involved in mating up a 3" downpipe. My turbo has no shaft play whatsoever, but I need to take steps ahead to get some power out of this car. Looks like I'm going to have to spring for different turbo and just shelf this little T3 for a while. Perfect. Don't under estimate the stock heat shields though. They do provide a significant thermal barrier. You can get a 3" but it's a challenge on a 280ZX.... here's an idea though.... Quote Link to comment Share on other sites More sharing options...
ZUL8TR Posted March 3, 2012 Share Posted March 3, 2012 It isn't that much of a challenge to build a 3" mandrel downpipe on a 280ZXT. See my pics above. A better description is below. For the first bend coming off the turbo, you need a 3" radius bend. Summit Racing sells them. Not all tubing suppliers offer a 3" radius. You cut the pipe right as it curves around and begins to run straight. It will fit just fine. If you do this, the rest is a cake walk. I don't weld. So I would work on a section, mark how I wanted it welded, then took to a buddy's shop and he would tack it together. Then back home to verify it fit and work on the next section, mark it, then back to my buddy for more welding. When I knew a section was perfect, he would weld up the joint. If I knew how to weld and had a welder, this was a weekend job. Look at the next pic and you will notice the DP needs a twist to clear the engine/tranny and then curve back to mate with the rest of the exhaust. The v-band flange you see in the pic mates to the exhaust. This section was made from two 90 degree bends. The top is the 3" radius. The bottom is a 6" radius. I cut the 6" in the middle of the bend. This allowed me to articulate into the twist I needed to fit. This shows the parts needed. You can see how tight you can get the 3" radius bend where the flange is welded on. It helps to do that first so you can bolt it in place, then work figuring out how to get the rest to line up. I should note that the 3" exhaust was done before I worked on the downpipe. The top left mates to the turbo. You can see the twist it needs. This is showing the flange that mates to the turbo. Notice it is a 2.5" vs the 3" on the opposite end. The T3/4 turbo I went with was set-up for a 2.5" v-band clamp. The flange slips inside the tubing and it was easy to weld it in place without having to use a 2.5" pipe. This shows where the DP mats to the exhaust. V-band clamps are great for doing all of this. Quote Link to comment Share on other sites More sharing options...
FricFrac Posted March 3, 2012 Share Posted March 3, 2012 (edited) Right I understand that but the outlet of a stock T3 is 2 1/8" so you would have a sharp edge from 2 1/8" to 2 7/8" or whatever your 3" inside diameter is. As far as I know a sharp step like that will cause significant turbulence which isn't good for getting rid of the exhaust at the exit of the turbo. Also the stock T3 doesn't use a V-Band flange. Also for the stock flange there is barely room to bolt it on to a 2 1/2" downpipe. I suppose if you were using a stock flange you could bump a 3" in where the bolts come out to allow it to be bolted on. Did your T3/T4 come with the v-band or did you need to modify it as well? Thanks for the pictures. Those are great! Do you have any pics of the downpipe back for the rest of your 3" exhaust? Edited March 3, 2012 by FricFrac Quote Link to comment Share on other sites More sharing options...
ZUL8TR Posted March 3, 2012 Share Posted March 3, 2012 T3/4 came set-up for v-band. Here's the rest of the exhaust. I paid a "professional" to build the CAT back. I think I did a heck of a lot better job. Quote Link to comment Share on other sites More sharing options...
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