RB25 stock manifold external wastegate

[wakotow]

So being a poor mechanical engineering student, and overboosting like mad, I decided that I needed to add a wastegate to my stock manifold.

Making the 1.75 inch hole turned out to be darn near impossible, so I did a 1" drill and then dremel the rest out.







After welding, painting and wraping.

Finally





This thing works awesome, but it scared the crap out of me the first time it opened up.

[GSDKinked]

Where did you get the adapter plate from for your mani???

[wakotow]

two of these and a little tig welding

http://cgi.ebay.com/ebaymotors...ories

[GSDKinked]

Did you drill out your old studs and get longer ones???

[Darius]

Ideal WG placement on the stock manifold. Nice work!!

[wakotow]

I got two out without any problems, but broke two off, my dad and I drilled them out but managed to save the threads, then just bought a set that were longer and put them in.

[l0nestar]

Nice!

[PorkChopExpress]

sweet. i just got done doing the same thing yesterday, only i just welded the flange to the top of the snail.

[wakotow]

You drilled the hole in the turbo itself? You have pictures?

[PorkChopExpress]

yep, the top of the hy35 snail is flat enough to weld the flange straight to it. cleared everything with the small synchronic wastegate.

im ordering parts for the intake and wastegate pipe today. i can have pics of it installed next week.

[meet07]

i always thought that runing that turbo with that spacer would cause the downpipe to not clear the steering wheel shaft?? guess it does....lol

what do you think all that cost ya??

[wakotow]

that's cool, I didn't think about just drilling out the turbo, that would've taken alot less time not having to pull the manifold.

Ya it does have issues clearing the steering shaft, I had to angle it comming off the vband about 15-30 degrees to clear (I didn't want to dent my pretty new downpipe), I'll see if I can get a picture of it, it clears but only by about 1/16-1/8th of an inch.

Turbo - 220ish shipped3" mandrel stainless 90 degree bend - 30ish4-3" silicone coupler - 30ish2.5" to 3" 90 degree silicone coupler - 30 ishMisc hardware (studs, hose clamps, nuts) - 20ish2 vband clamp + 4 flanges - 75ishstainless braided line (oil feed) - 20ish2 M12x1.5 to -4an fittings - 30ish2 90 degree -4an DIY hose fittings - 30ish3" braided exhaust flex joint - 20ish2 .5 inch T3 spacers - 15ish

Total - 520ish

Then the wastegate came later but that wasTial 44mm wastegate 345shipped1.75" mild stee J bend - 25ish2"x15' exhaust wrap - 10 maybe1 can of 2000 degree black spray paint like 6 bucks or something

Total - 390 ish

So about 900 dollars total.

I accumulated the turbo parts over the whole summer (I ordered the turbo first in may and got it installed in august)The wastegate happened in 1 week, I ordered it sunday night and the next sunday it was installed and I was running again.

[amakadius]

i like

[DETurbine]

Like what you have done. I just had a 38mm flange welded in the same position as yours. It's a cheap way of doing things, but functions great.

[Fibre guy]

I did something like yours but the manifold cracked... Many people on the aussi forums have done this mod and the manifold always likes to crack right under the cast bridge in the middle on the 4th runner. Mine cracked right through the bridge though. (MIG welded and 5 min. break between welds but I kept the manifold heated at around 140*. (best for welding mixed metals)Just a heads up on where to check if you hear an exhaust leak.

[240z4u]

I did a similar mod about 2 years ago or so... and no cracks. I think it also depends on the pipe you used.

Looks good!

[PorkChopExpress]

your supposed to use a high nickel filler metal between the two like Ni99. my tig welder is in storage and is like 600lbs so its staying there lol. so i just stuck the cast piece in my kiln let it soak at 1000deg welded it up with mild steel mig wire and stuck it back in the kiln to cool overnight. if it cracks i guess i will just braze the crack.

[wakotow]

I know that welding two different materials is pretty sketchy, however, I've had decent luck doing the same thing to my dad's sr20 gtir manifold, and welding a stainless bung to the stock cast downpipe. All I've done to prevent stress increasing is to weld very short amounts less than 1/2 inch at a time and letting it cool down before the next round of welding. So this piece took about 3 times of welding to finish it, and it seems just fine, but I will keep an ear out for the leaking...thanks.

If it does start breaking then I guess I'll pull it and reweld it. And then start looking for a real manifold.

[Seishuku]

Preheat it to around 500 degrees F, and use a nickel rod, I like to use a 625 Inconel filler.

Works great for welding both stainless and mild steel to cast iron, or fixing a crack in the casting.

Edit:And PorkChop already said the same thing. lol

[240slidekat]

so did it get rid of your boost creep? im on the same boat right now. tried porting the internal gate but still wouldnt hold under big load. let me know how it works out for you. how much boost are you boosting anyway.

[wakotow]

Oh it does a fantastic job of keeping boost to where I set it. I'm at around 14 psi right now, I'd like to run about 19 but my ecu really doesn't like it. I'm looking into nistune right now and see how that will work for me.

[240slidekat]

what rpm do you see full boost?

[wakotow]

16psi at or around 4000, and back when I didn't have a wastegate that worked it was 20ish around the same spot, maybe 4500 but I doubt it's there after that. I'll try again on the way home and see what rpm it hits. It just doesn't feel like I want it to, maybe it's the ecu, maybe I have a small boost leak, maybe both but right now 16 psi feels about as good at 12-13 felt, not bad, but that turbo wants to give me so much more, I can't wait till I can bump it to 19 or so and let it roar.

[wakotow]

I have 16-17psi at 4200 or so

[Cjmartz2k]

What is that, an HX35? What's it tuned with right now, and what gear were those spool figures in?

[wakotow]

Yes that's an HX35 the 7 blade, so spool is supposed to be a little slower but with a little more top end. It's kindof tuned with a SAFC2...

That was 4th gear going from about 45 and the putting my foot on the floor. When I'm going from the top of second to third though it's instant, pretty much as soon as my foot is off the clutch my wastegate is fully open.

[240slidekat]

i also have a 7blade, cant wait till i have external wastegate mounted. as of right now it holds 18 in second gear, third gear who knows, it just keeps on going. thank god i have a built motor and enough fuel supplied or else it would of been BOOM!

[Cjmartz2k]

Wow, stock injectors and a SAFC? Dude, that's why it's so slow. My full boogy HX40 was at 14psi by less than 4000rpm, and I didn't even have VCT any more. Time for a Power FC or something like that to do that thing justice. You'll need at a MINIMUM 550 injectors for that thing, and that's only if you don't get nuts with the boost. What kind of fuel pressure are you running?

[wakotow]

I actually can't tell if I have larger than stock injectors or not. When I got the car the guy that sold it to me said it had upgraded injectors. But when I pop off those little caps they look stock to me. He told me they were 550's, right now I'm running stock fuel pressure (43 at idle with the vacuum line pulled off) and my safc is around -15% across the rpm band. Actually if anything I think I'm running a little rich, 11.5 to 12, and a little lower in the earlier rpm, maybe I'll try pulling a little fuel out down low and see if I can get it spooling a little faster.

As for the ecu, I think I'm going to go with nistune, I can afford it and I think it'll be powerful enough to do what I want it to.

[Cjmartz2k]

What color are the injectors? Purple/grey or red?