Dat73z

Investigated the progression port covers a bit more. The orings are some obscure metric size. I don't quite have the right sizes (too large or small) so I'll measure them out a bit later today and order an inbetween size to try for a bit more squish but not too much.

@LooseRocks there are themostatic plates, but when I disassembled and restored the ZXT oil cooler plate I was under the impression that there is a thermostat built in. Not sure what the best approach here is as it's overcooling on the street even obscured but I think it should work out well for 20min WOT boosting sessions on the track. Unfortunately I still found some smaller puddles of fuel at the carbs. It is certainly less than before. I'm thinking it may be the progression port covers as the orings in there are some tiny metric size. I think I'm going to see if I can find some suitably sized replacements or maybe try some sort of sealing washers. I could easily loctite them and have 100% seal, but that would leave residue and possibly be a pita to remove for service.

I put another 30 miles on the car this PM. In 78F weather obscuring the oil cooler by 2/3rds let my oil temps get up to 168 or so over the course of an hour or so on and off the boost, and in stop and go Fri Bay Area traffic. It still drops like a rock when moving but not like it did before. An unintended consequence is my water temps seemed to be slightly higher for this kind of weather, maybe 210. So I think if I'm going to be stuck in traffic during a heat wave like driving through LA or SoCal I need to ensure there is no obstruction at all.

Had a few mins this AM so I partially obscured the oil cooler with some cardboard. Clearances are so tight I could barely wedge a piece large enough to obscure the cooler by maybe 2/3rds. With temps dropping into the 50s in the AM now, I'm getting significant oil overcooling issues. The highest temp I've seen was 180sF oil temp at the pan on a record 107F day sitting in traffic after boosting. Hopefully this doesn't block the airflow coming out of the IC too much.

There surprisingly isn't a lot of blowthrough dcoe info for datsuns, although there were plenty of off the shelf kits developed for our cars through the decades. Maybe this thread can serve as a goldmine of info for that. After reading all sorts of blowthrough rotary and v8 forums posts ranging from all out drag cars to street and road racing I'm going to see if I can keep the FPR reference at the top hat to see positive pressure only and attempt to resolve the low boost vent/response issue with a normally open BOV. So off boost, the triples should respond as I've tuned them NA, which is a very small portion of the dynamic driving range, but the one which is used the most on the street. At WOT and if I actually get on the boost, my current SSQV BOV fully vents and all is good. But at low boost settings it flutters which sounds cool but leaves some residual pressure in the floats causing enrichment until the engine burns it all off. I've placed and order for the new BOV so hopefully it comes in before my dyno day.

Things got really busy but I was able to spend maybe 10 mins today working on the car. I installed the cup washers and orings then reset the needles to my baseline. Technically I get tomorrow off but I'm working through the weekend too. Hoping I can squeeze a couple hrs in to try using the Gunson to get the idles dialed before heading out on Saturday...just a bunch of little projects which all take time.

Tonight I went for a short drive and met with the Datsun Europe people who were really cool. Have been meeting with lots of random people lately I think because JCCS recently wrapped up. It seems the orings on the idle mix screws are working at low boost at least. Tomorrow when the cup washers come in I'm going to try using a Gunson colortune to adjust the idle mix for each cylinder. I tried the listening/lean-rich extremes approach but the car is just too loud so I've been adjusting based on plug color. Of course this is a very iterative and subjective process. Hopefully the Gunson tool will work better.

As a temporary stopgap I've installed orings and washers I had around. I ordered the cup washers and to my surprise they'll be here tomorrow so I'll put those on when they get in, I thought it would take a few days to a week. I need to recalibrate my idle mixture screws anyways for each cylinder so the timing is good.

I didn't have too much time last night to work on this but upon visial inspection my OER carbs lack the cup washers and orings on the idle mixture screws. I know my last set of weber DCOEs I rebuilt had them. I don't recall if my Mikuni 44s had them. At this point, I think the idle mixture screws and progression port covers are the only areas which I haven't taken a close look at sealing. Fortunately I don't need to remove the carbs again to seal these areas. Everything else seems to be well sealed. So I'll order some cup washers for the idle mix screws and hopefully that will help seal those areas on boost. I also have some ideas if that doesn't work. When boosting through dcoe carbs it is apparent that is a lot of fine attention to detail is required to ensure they are adequately sealed. I've seen some pictures of blowthrough setups where these details weren't addressed and it's apparent from the fuel staining that the carbs were just run with fuel and boost leaks.

Went for more shakedown boosting tonight and caught some more fuel leaks. Perhaps from the idle screws or progression port covers on all 3 carbs. They've been bone dry for weeks so its curious it all happened tonight. I'm going to change the o-rings, clean up the area and check again on my drive tomorrow. This weekend I will take the car for a few hour high speed shakdown and visit some friends in the East Bay.

3.2 stroker turbo. I could get more out of it, but it's blowthrough. Have a thread in the turbo section of the build so far

I'm running a Q45 R200 SN 3.54 rear end. I think our #s are similar though, at 9PSI on Rebello's dyno my engine made 370HP @ 6k rpms, and 370 trq around 4k rpms. I've spun the R compounds in 2nd and going into 3rd. Our driving styles are different, I'm setting my car up for street and occasional HPDE targeting 3-400whp/trq. At 8psi or so I'm happy with the car as-is since I mostly like to go cruising with friends.

Dude are you my twin? Pic of my car from like 2016-2018 timeframe Lol. Yeah if it was me I'd just run the r180 until it blows. Tbh I would still be running my sti r180 clsd but I found a buyer who wanted it all and my buddy was parting out his rear end to go with an 8.8 (turbo nitrous LS drag car). Maybe post it for sale and see if there's any interest at a good price while you keep driving it. With your driving style though it sounds like you've been blowing trans as a "fuse" before your rearend goes. So maybe after the CD something else would let go.

Thanks, I would appreciate that @rossman. Generally I'm looking at how the compressor is mounted and the lines are ran. I've been templating things up with cardboard on my car and I think I want to run the lines with angled fittings from the compressor through the rad support to the condenser. Then from there run the lines in front of the rad support with the dryer and tuck them in the pass side fresh air duct into the cabin. I like how your setup looks tucked above, it's really clean. Looking at pics from your build and others help me visualize the routing.

What does your trq look like? I have spoken to a few thay have dynod Rebello motors on chassis dynos. I will be one of them as well in a few weeks. Assuming a 20-25% correction factor, you're sonewhere around 250whp/wtrq. I think the 8.8 would be overkill for just about all driving conditions at those levels, but you do get the tunability benefits of the 8.8. Fwiw Edit: What trans are you running? I have a setup that had once carried the tires on a nitrous v8 (R200 SN) but the weak point in my system is the trans. I will grenade my trans before exceeding the limits of my diff.

After some discussion on FB groups with Tony D, I may try some different vacuum line routings for the FPR in addition to the tunable BOV. The SQV is close but it seems for blowthrough applications the immediate vent and fuel pressure drop is critical for transient street drivability. If I was building this car as a dedicated track machine, I wouldn't care. As-is the drivability is good, but I'd like to make it better. I've been trying to find an adjustable BOV to borrow and test before dropping the coin on a new one but no luck so far. If anyone has a lead in the Bay Area, CA please let me know.

Did one more long test drive yesterday evening and realized now with the 70-80F temps I'll need to obscure my oil cooler. It takes 20-30mins to hit 140F at the pan from slightly warm/fully cold and on the freeway it just drops into the 130s and keeps going down. So since we're going into the fall I think a piece of cardboard will do it. The 105F days were unbearable but they let me fully stress test the cooling systems and everything stayed cool even after boosting around and idling through CA traffic. I really do need to install AC though to keep the occupants cool because at 105F in stop and go traffic you are melting into the seat.

Thanks @rossman. Still havent had the chance to do more research but I did bookmark some install threads to read this next few evenings. Tonight I spent my 30 mins investigating the BOV further so I went boosting around. I had a vintage 80s HKS standard BOV which uses a standard spring and diaphragm. As I suspected, it actually responds slower than the SSQV4 as verified on my AFR gauge. The SQV works ok and an improvement over what the surge tanks came with but I want to get this dialed before dyno day so I'll need to order a new BOV which varies the opening pressure based on boost level. Fortunately I think the SQV4 is popular now with the modified car crowd due to the flutter noise so hopefully I can recoup most of my cost at sale.

Aydin, fwiw on a street driven turbo Z and setrab cooler I was struggling to hit 180F oil temps boosting around for hours during this last heatwave of >100F days in CA.

So I finally got a dyno date set with a local tuner this AM for the 1st week of November. For allocating my limited time to actually work on the car, on the critical list of items to resolve between now and then are: 1. I need to source a new BOV and plumb that in (maybe Synapse Synchronic) as my current HKS SQV4 flutters at low RPMS/boost and that affects response. Unfortunately I think they've been backordered for a while but I'll give them a call and see when I have some time. 2. Continue street tuning the fuel circuits to the best of my mediocre tuning abilities. I'll save the timing curves for the expert as I don't trust my ability to sense knock/detonation since the car is just so damn loud. 3. Add a boost controller as I'd like to ultimately run the car around 1 BAR of boost. 4. General tuneup and inspection 5. More heatshielding/ducted blower fans I think if I dedicate maybe 15-30 mins/day I can accomplish these tasks between now and then.

Tonight I started back in on the AC fab and started templating the brackets for the compressor mount in cardboard. I think I will make this my fall/winter project. I'd like to also fully upgrade the hvac unit to a vintage air but I'm not sure which model to get. I'd like to somehow retain the OE hvac faceplate and controls for that aesthetic so I'm not sure how I'd integrate that but I'll spend the next few days doing some research. I also started measuring again for an Accusump. I think I had determined a 2 or 3 quart unit would fit perfectly in the teal location. Still undecided if I'll pursue this mainly because my car already takes 10 quarts of oil.

Since I have the car moderately street tuned I figured it's time to start returning jets to my buddies who graciously lent them to me. It was a nice moderate day for some boosting so we went out cruising. The mic doesn't really do a good job of picking it all up but it's pretty visceral. The turbo/stroker noises and the feeling of raw torque just sucking you into the seat. I'm really glad I decided to start building this car again. Over this past year I've met a lot of cool people and seen a lot of sick builds. Can't wait to get this thing on the dyno and really dialed in. VID_35530614_121347_916.mp4 VID_35530615_100712_812.mp4 VID_35530616_012528_333.mp4

As a follow-on to the above post, another benefit of running smaller jets is how the surge tank amplifies all circuits. For a race car perhaps it doesn't matter but since I'm mostly street driving for now, for example, if I'm quickly going into boost and skipping the progression and say I need to slam the brakes to quickly stop for a traffic light, I can make the mains come on so hard and with fuel demand dropping so quickly/bov immediately venting the engine will just start to rich stall then quickly recover at idle braking down to 0mph. Sizing down the mains/airs to maintain 11-12afrs and bumping the idle timing anti stall resolved most of this. So it's a fairly delicate balance for a wide range of street operating conditions. It was clear with the tune from the engine dyno session that it was set up for race car WOT power rips.

This morning I played with some jetting a bit more and performed a general inspection. I had reseated some gaskets on Carb #3 which was leaking a bit of fuel a few a few weeks ago and it looks completely dry. On tuning, I've observed the surge tank basically amplifies the characteristics of whatever emulsion tube and jets you're using compared to NA. So for example, the f9 emulsion tube which leans the transition and richens the topend was barely doing that NA, but on boost it was doing that a solid pt afr on either end of the afr spectrum. I wanted to richen the transition and lean the top end so I put in f16 tubes back in yesterday and it did exactly that. I have the majority of the curves 11-12afrs across the board so now I'm fine tuning at the transition, which sometimes leans to 13s if I'm high gear, high load, low rpms transitioning/rolling into boost on the progression but not a problem gears 1-3. Simple solution is to drop a gear but when I'm cruising on the freeway (s13 jdm trans/3.5 rear end) I'm at 2-3k rpms in 5th which is right before the mains tip in and the turbo is just starting to spool, so it would be nice to just be able to roll into it in 5th for passing off cruise instead of dropping to 4th. AFRs cruising in 5th are 11-12 so they'll creep into the 13s easily rolling into boost at that rpm range. Perhaps I can raise the fuel level just a bit as well to richen the curves up and lower the tip in rpms...but I also want to stay out of the mains on cruise for economy. But I could also take the easy way out and raise the levels anyways since I'm not exactly driving this car for economy. After months of fine tuning my strategy here is to use the smallest fuel sizes with the largest air bleeds possible. I've found this makes everything more responsive off boost. Since the dcoe type is basically 3 overlapping circuits/fuel curves (idle, main, pump) I may not be able to tune this out without making a compromise elsewhere like richer idle/cruise but this isn't EFI where a few keystrokes can tune it 😄.

Maybe ask to speak to another engineer. Do you have a picture of what you're torquing into? For some reason I'm thinking the floating hub adaptor for the rotor but perhaps I have the wrong idea. I ask because for steel into AL which is constantly heat cycling through the extremes, I always use some form of anti seize to prevent thread galling but that can also change the torque spec. One thing you may also want to consider is drilling and safety wiring all brake and hub hardware. It's a bit more incremental effort on the frontend, but worth it for peace of mind.