Triple Blowthrough Turbo

[Dat73z]

4 hours ago, madkaw said:

I don’t remember , but it was very pricey and the holes didn’t hit the lash pads very well. I have a couple extra spray bars if you run into trouble. I do t use them

Thanks for the offer 👌 I may take you up on that if this one doesn't work out. 

[Dat73z]

Been a busy week but finally getting back into this. Trimmed a spare valvecover to fit over the oil spray bar and buttoned up the rest of the fuel tank. Ended up running teflon AN washers on either side of each bulkhead fitting with a washer on the back to spread the load. Routed the return at the top of the tank which feeds back into the top of the black box. Hoping for no leaks and adequate return flow to maintain 3-4 PSI at the carbs with no boost. 

 

Still waiting for the AN fittings and stainless hardline to come in, but plenty to button up this weekend. 

[madkaw]

I’d rig up a driveshaft to drive your oil pump before start up to get everything primed and to check how well that spray bar works 

[softopz]

IF im not mistaken the the thread is m10x1.25 on the manifold side and the turbo side its coarse thread 1.5

[texis30O]

LOL I stumble on this just in time.  I am about to embarqe on a Cartech install for my 72 240z.  I would like the power to be at least 400whp ( which is about 1/2 of what I have on my 70 240z) This build I am going with period influences with a modern twist for reliability..... Since I am in TX and just down the road from Corky Bell I will be leaning on him for the final approvals.  Good luck on your build as you have done a lot of things I am leaning to.  I have picked up some good ideas in here.... What are the specs on your turbo as I will be updating that as well from the old unit to something new....

[Dat73z]

On 11/8/2018 at 4:53 AM, texis30O said:

LOL I stumble on this just in time.  I am about to embarqe on a Cartech install for my 72 240z.  I would like the power to be at least 400whp ( which is about 1/2 of what I have on my 70 240z) This build I am going with period influences with a modern twist for reliability..... Since I am in TX and just down the road from Corky Bell I will be leaning on him for the final approvals.  Good luck on your build as you have done a lot of things I am leaning to.  I have picked up some good ideas in here.... What are the specs on your turbo as I will be updating that as well from the old unit to something new....

 

Sounds like a neat project. Turbo setup is a standard Garrett ball bearing T3/T40E 50 trim/63 AR with the ATP ultimate internal gate, Tial 10psi actuator. What will you be running for ignition? 

 

Keep me posted on your build, always looking for more perspectives 👌

 

Build is still moving forward. Just got back from a long work trip and it's too smokey in CA from all the wildfires to make good progress.  

[texis30O]

On 11/10/2018 at 4:21 PM, Dat73z said:

I am looking at running with a COP set up or a LS coil set up.  I have a SixOne Industries distributor that I can run or possibly a 123 Ignition unit.  I don't want to keep the old distributor set up on it. 

I know I want to verify the correct oil pump, if I don't have a turbo oil pump set up I will go with something aftermarket. 

I plan on making sure the head and intake/exhaust manifolds are port matched. 

I noticed that your Mikuni manifold is set up like mine. Mine was plumbed to read pressure from each cylinder and sent that to a common canister then 1 hose coming out to read pressure in a in cabin gauge. 

I am going to upgrade the oil pan to a 6qt Moroso. 

The head has been worked over and has a cam of some sort but I do not have any of the specs on it.  I am hoping to find out.....

The set up I am rebuilding has the old RotoMaster turbo on it which will be wall art.  I am going to updated it with a new BW or Comp Turbo unit.  I am going with a larger intercooler than what was on there originally. 

Sounds like a neat project. Turbo setup is a standard Garrett ball bearing T3/T40E 50 trim/63 AR with the ATP ultimate internal gate, Tial 10psi actuator. What will you be running for ignition? 

When all is said and done I am hoping to be 400-50whp. 

👌

 

 

 

[texis30O]

[DuffyMahoney]

2 hours ago, texis30O said:

Wow that is a lot of oxidation.  

[texis30O]

The car was near the ocean.... like feet from the ocean in a garage

[DuffyMahoney]

17 hours ago, texis30O said:

The car was near the ocean.... like feet from the ocean in a garage

Yeah, I kind of figured something. Vapor blasting the carbs would make them look the best.  But they will always have pitting.  

[Tony D]

I never got the transition correct using the Cartech Style non-diffused plenum. Always had a transitional lean spot and was not up for modulator rings so went EFI (HKS ITB's)

Max Power and WOT was comparable between Cartech Plenum, and the HKS T-1...but the refined drivability of the HKS spoiled me.

 

[Curtball]

Still cant get my hands on any hks itb. Considering going with the borla 2900 series. You have any input on those Tony D ?

 

https://www.borlainduction.com/2900-series.html

[DuffyMahoney]

On 12/30/2018 at 7:00 AM, Curtball said:

Still cant get my hands on any hks itb. Considering going with the borla 2900 series. You have any input on those Tony D ?

 

https://www.borlainduction.com/2900-series.html

The borla's sure look good!

[Tony D]

Borla bought out Gary Pollard's TWM Induction in Goleta. They're a nice piece.
A but less spendy due to the exchange rate are the bodies from EFI Speed down in Oz. They have nice kits complete, then sell off their manifold for some bucks if you have a better one or like me ran the Mikuni for the clearance.

Thanks to 24OZ in the UK, I now proudly possess both 45mm HKS ITB's and his old set of 40mm HKS ITB's. Sadly he went with newer Jenvey's which are problematic in the blow through configuration. The quality was not up to what we expected due to the hype. I would hope their "Heritage ITB's" are better as that carburettor look with concealed injectors and TPS does lend an authentic vintage look to the whole works, without the Carb Hassles!

 

[Curtball]

Thanks for the input 👍 Tony

[Dat73z]

Wow I can't believe it's already been a year (married, house sale, moving, etc.) but this build goes on. 

 

Just dropped off the random stroker parts, spare n42 and p90 head I had laying around to Rebello earlier today. Figured it would be easier to drop them off at his shop which is local to me rather than keep moving them around while we're getting re-rooted. The new engine setup will be a 3.1 stroker, knife edged ld28 stroker crank, forged rods, pistons, p90 solid lifter head with supertech valves, headwork custom cam, ported mikuni short runner etc. Hopefully done in a few months and hopefully ready to throw back in if we can close on a new house sometime next year. 

 

Still need to decide on a compression ratio. Apparently my p90 head is straight and virgin according to Dave when he measured it out earlier today. I'm thinking 8.5:1 for safety on pump gas and off boost response but Brian and Dave mentioned we could go up to 9:1 if we shave the head. Seems risky esp with 91 CA pump gas. Car will be primarily street with some track time @ laguna seca which is my closest track. Any thoughts? 

 

I should probably add the custom pistons have a quench area which matches the p90 head. Dave was talking me through the benefits but some of the details were over my head having never built a stroker turbo motor myself. 

Edited December 11, 2019 by Dat73z
Details

[Tony D]

I see the edit regarding drilling the carbs.... Are you meaning you enlarged the holes on the carbs to allow movement to accomodate both the pattern on the box, and the pattern on the manifold (basically made the holes bigger so you could jigger the carbs around to get the lined up and the fasteners to fit?)

This has been a known issue for a time on the later boxes, don't know why they got funky on the hole drilling some fit some are quite a bit off. On the ITB's (which was really the design for these) some of the fuel rails interfere with the box and you need to spacer it out to fit, this makes for a great opportunity to fix it up permanently!

What you do is bolt up the carbs to the manifold properly, and level, with proper hole centering on the studs. Lock them down. Then on the spacer plate you lay out your holes to they allign perfectly and fix them to the carbs using countersunk allen-headed screws. This fixes your carbs immovable, and allows you to synch them with the box off.

Now, to attach the box to the plenum, my personal favorite is to use O-Rings on the holes and make some EASILY ACCESSIBLE M-8X1.25 or M-6X1.00 in a pattern around the edge of the spacer plate. Yeah, you're drilling into and HKS Box, and tapping it (and if you're smart, putting in Nutserts, roseann inserts, or keen-serts and installing long studs that allow you to pilot your surge tank onto the spacer plate and secure it with nuts and washers on teh backside of the spacer plate. I wish I had photos of what we did for the guy in UK but it worked treat and now he can drop the tank in 5 minutes without touching the carbs at all! putting the fasteners where you can GET to them makes bolting it up SO much easier! In fact, I'm considering a 375" thick spacer plate just to use O-Ring Static Seals and the studs on my HKS 45 ITB's. I don't have a clearance problem at all and the extra 10mm of the box won't be an issue either.

Just some food for thought on another way to do it without hogging out the holes on the carbs. They really should be level and all in the same plane. I'd recommend you check your fuel levels per carb and check the float bowl for level barrel to barrel as if they are angled one barrel respective to the other in the same carb, the same jets will run richer in the lower barrel than the upper barrel and under boost when the differential pressure elevates the fuel in the jet wells that can really add headaches to getting cylinder-to-cylinder mix correct.

[Dat73z]

Thanks for the feedback Tony. Wish I had known your tips for the funky hole drilling on the later boxes before. Useful information if I ever go for another set of carbs or ITBs in the future. I had considered making a spacer plate at that time but just ended up drilling out either end of the carbs taking care to ensure everything was centered and level. I think my concern was that even with the Mikuni short runner the manifold inlet on the later tank was coming pretty close to the shock tower. In hindsight making a spacer plate would have been easier and less time consuming. As I was measuring I also think the previous owner of my car had already "clearanced" the bottom of the shock tower lightly above the frame rail back when the car was drawthrough turbo.  

 

Edit: Specifically what I had done was drill the holes enough to remove the threading where the trumpets used to mount via studs. The spacing at this point at the front of the manifold looked good with the bores for each carb aligned to the holes in the HKS v2 Surge Tank and the float tank pressurization port aligned as well. These dimensions looked ok and I bolted them up with stainless hex head hardware. I then had to drill out the rear mounting points for each carb to line up with the Mikuni manifold. I took care not to really hog out the holes. Just enough to be a hair under an interference fit with the manifold studs when slipping the carbs + surge tank on. I don't know what the ID of the Mikuni runners is but the OER 47 and the phenolic? spacers are much larger. I think Rebello is going to port everything between the head and the carbs- I'll need to confirm this. 

 

A question for you Tony if you read this and have input: How is venturi selection affected in a blowthrough setup? I currently have 36mm venturis on the OER 47s (the smallest they make for these carbs). I figured the smaller venturi would be good for off boost throttle response. I see NA cars running much larger venturis on these carbs, but we're cramming a lot more air in with the turbo. 

 

Got an update from Rebello earlier today- motor is moving along quicker than expected and they're already machining the block. We settled on the 8.5:1 compression ratio. BHK? dual row damper with a trigger wheel was selected in the event I decide to move off the 123 unit. Cam selection is still in the air. 

Edited December 19, 2019 by Dat73z

[Dat73z]

Bringing this build back from the dead.

 

Wow I can't believe how much time has flown by, especially this past pandemic year.

 

Ended up moving 3x since my last post but we're finally settled back in now and I brought the car along with me for that journey the entire way doing misc. things here and there. Finally got my garage partially set up and my engine is finally on the dyno as of this week @ Rebello with the blowthrough setup. 

 

Since the last post I've put in a q45 rear end, fuel tank, stainless hardlines, did a custom fan shroud, bunch of other random items. Got a day off from work this Fri so the current motor is coming out for final engine bay prep. 

 

Will be updating this thread again as the build progresses.