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1971 240z rb25det build thread


5thgenluder

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David how do you like the sti setup? That's the direction I'm leaning toward. How had it held up on the strip, street, and auto x?

 

Sorry for the late reply I was really busy at school :/ Well during acceleration I did feel an increase in traction. I have not really went all out for auto x with the set up yet. I will tell you that I am able to handle corners better with the lsd. I took it down to a local canyon and it is a completly different feeling with lsd much more grip.(confidence to drive faster through turns) Since, when I did the swap I also installed new bushings for the whole rear suspension my ride is a whole lot smoother. I have done burn outs, hard pulls, and donuts and my axles seem to hold up with no problems. The r180 casing on the sti diff seems a whole lot smaller from the s30 r180 but don't let that fool you of it potential. :)

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  • 4 weeks later...
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Rear end is on hold. Ad some nice weather here in Chicago spent a little time in the car so far. The car has a tough time staying running on decel. The battery was dead so I replaced that. The more miles I get to put on the car the more I realize how bad the ride is. The rear struts are blown and I am dealing with some 40 year old bushings. My current priorites are as follows.

1. Get the dying on decel issue fixed. Sealing outside help with that one.

2. Suspension. Have bushings looking at coilovers. Want an easy solution. Like the ttt coilovers and the mckinney.

3. Brakes. Gonna do the toyo 4x4 coversion or the silvermine.

4. Diff. Still haven't figured this one out. Leaning toward open r200 with the intention of adding an LSD down the road.

 

Right now it's overwhelming. It's time to start cleaning up all my shortcuts from install. Ie wire management, cover for spare tire well, connection oil cooler, programimg fuel gauge, going over every nut and bolt. I also have 350z seats I'm want installed and I hate how thin and big the stock steering wheel is.

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HELP. I can't figure out this noise. I'm taking it in next week but I want to know what could be causing this. I had mentioned earlier it wasn't running right. But here is what happens. Under boost the car pulls hard and strong. Then around 3-3600 rpm it makes a terrible sqeelching noise and almost has a feel like I'm hitting te redline or it's stuttering out. I took a sound clip. You will know the noise when you hear it. I did it 3 times in this clip.

 

Edit. Won't let me post sound clip. :(

Edited by 5thgenluder
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Good news. I solved the squelching/losing power problem. Turns out that when I removed the Ic piping to have the bung welded on. I forgot to tighten the clamp that secures the coupler onto the throttle body. So when I built pressure it was blowing the air out around the seal. Now I have a new problem. I can't maintain idle. I set the idle set screw. Then as soon as I rev it up and release the throttle it stumbles around 400 rpm. Usually dies out also. Any thoughts?

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Good news. I solved the squelching/losing power problem. Turns out that when I removed the Ic piping to have the bung welded on. I forgot to tighten the clamp that secures the coupler onto the throttle body. So when I built pressure it was blowing the air out around the seal. Now I have a new problem. I can't maintain idle. I set the idle set screw. Then as soon as I rev it up and release the throttle it stumbles around 400 rpm. Usually dies out also. Any thoughts?

99.9% of the problems are MAF related. That is the reason why i went with stand-alone ecu that runs on Map sensor and not on MAF.

make sure that your intake pipe is secure to the turbo and that there are no leaks. that is just ac critical as all the piping on the intercooler and the throttle body that you said forgot to tighten. also check if your tps is adjusted properly.

 

Bohdan

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well so far I have checked the hose from the iac to the ic. Carb cleanered all the vacuum lines looking for a leak. Tightened every coupler on the ic piping and the coupler that holds the maf to the turbo. I have tightened the bov ( still vent taking it tomorrow to switch it to recirc and also have a 12" section between the maf and turbo). That could be some of my problem. I am running super rich. Its gonna be a long 30 mile drive to the shop tomorrow with the car stalling out at every light. I am also getting a strange voltage flutter. As the motor hunts so does the voltage. Here is a video of what Im dealing with.

 

=

 

 

edit: just checked. I unplugged the maf and that fixes the idle issue. It holds a steady 850rpm. Obviously I cant rev over 2000rpm. I am thinking I might drive it with that hose clamp off tomorrow. At least it holds idle even though it wont build boost.

Edited by 5thgenluder
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No, it should be like an orange or redish sticker. Green is for the RB20. If your running stock ecu, you have to make sure that you get the right one or else it isn't going to work.

 

And remember what I said about how the MAF has to be positioned. It is important. Your also going to have to recirc your blow off valve unless you like your car shooting flames out the exhaust and making a loud bang noise when you let off after load in addition to dying while inching forward at stop signs and such. Believe me, these things get very annoying very fast and your car loses efficiency which is not worth the little pssh noise.

 

I think Jake called this one. From what I'm experiencing I think it has to be the Maf placement and the bov setup. Car is running super rich. I have read that a bov can cause this cause the maf is looking for all that lost air.

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Well I got the fuel gauge calibrated. Filled the tires with air and took the 30 mile drive to my speed shop. They have it till weds. As of now they are adding exhaust hangers and welding my muffler on. Making the seat brackets for my 350z seats. Making a charge pipe for my maf and recirculating my bov. Then if that doesn't solve my idle issue they are gonna dive deeper into the motor. When I get it back I will clean the very very dirty seats and take some pictures.

ztr. I agree but I can't afford the LSD swap and the suspension. Maybe I have my priorities backwards but the ride is very bumpy, and that's an understatement. The shocks, springs, and struts are all stock. It's like it has no suspension at all. Just a bumpy mess and feels unstable at 55+ mph. Don't get me wrong the stock diff is not gonna hold that power but I'm thinking that being able to slowly drive it in comfort is better than being able to drive faster than the rest of the car is prepared for. What do you think?

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Well the shop got backed up on another project. No eta as of now. Miss my baby. Also asked them to weld a bung on my exhaust for the zeitronix wideband I plan to purchase this summer. Can't wait to get her back. I think I've decided to get the ttt coilovers as soon as I get the bill from my shop. Here's hoping its a small enough number that I can buy them right away. Then I'll move on to collecting diff parts.

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Have you decided on on what diff youre gonna use? Im thinking of going with the r200 short nose out of the J30 infinity. its the same as the q45 buy has a 3.90 gear. I decided to go this route because if anything breaks in the diff then i can justgo to the junk yard and get another. its not the same with the longnose. Its also because I'm planning on running 700+hp through it. In your case it might be different.

 

Bohdan

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I am leaning towards the long nose r200. Plan to do an obx LSD down the road. I'm not 100% sure. I'm bummed that I have to pay to have my McKinney driveshaft modified with a new diff. Thats why I wanted the sti r180 but I've been told it doesn't hold much over 350hp.

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I would recommend 4.11 ratio. I have a 3.69 and i dont come out of second until 79mph. 134ish in 3rd and saw whatever the top of 4th was on the dyno. Way to much gear with the R34 trans and 3.69 I think i run out of downforce around the 165+170 range.

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Zt-r. I was planning on doing a 3.9 but would prefer a 4.11. I wish there was a better diff solution for our cars. It's very expensive when you start adding it all up.

Update. Picked the car up today. So far I like the way the seats turned out and the new intake pipe and recirc valve looks good. Bad news is McKinney sent me the wrong exhaust so they couldn't fix that. Also the idle is still terrible. I have to have a vacuum leak somewhere. Or the iacv is bad. Also on the way home the ride was terrible again. Something about it just seems sketchy at anything over 50 mph and it was so bumpy and bouncy it made me sick at one point. I am also unhappy with how low the exhaust hangs. I need to get that worked out.

To do list. (in order of priority) 1. Find vacuum leak and or figure out idle issue. 2. Get correct muffler. 3. Get exhaust tucked under the car better. 4. Suspension. Gonna go with t3 coilovers and do camber plates down the road. 5. Differential. 6. Desert z rear brake conversion kit 7. Silvermine front brake kit.

That's the plan so far. I know their is a heck of a lot more to do. Pics of the seats coming after I clean them and have some sunlight.

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Did a little work today. Trying to solve the idle issue. Tightened the intake manifold and iacv. No luck. Then I read how to use read the ecu codes. 1st time I got a code 12 which is maf. Reset the ecu. Went out for a drive. Got the car up to running temperature. Check engine light came on and bad idle returned. Then the next part is weird I tried to check the code and it was 55 all good. Why would the light be on and the ecu have no code stored?

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Had a little time today. Removed and cleaned the iacv it helped a little. I am getting a much better idle. But the motor still drops to like 400rpm on rapid decel. But at least it's drivable. Talked to Mack at McKinney he is gonna help me with some exhaust issues. Plus I have some surprises in the next few weeks. :) I am getting some backfires at wot. Plan is to check timing. Never set it :(. Also replace and gap the plugs. What do you guys recommend for a stock rb25det?

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I used some carb cleaner to search for a vac leak. Couldn't find anything. Checked tps voltage today and adjusted the idle set screw. I've got it idling fine. A little high 900-1000rpm but it no longer stalls. No spark plugs to be found ordered Ngk copper ones should be here Friday. Set the timing. Pulled 1 plug and the gap is way off. So hopefully the new plugs will help even more. Only problem I still have is the drop in rpm on rapid decel. Goes down to about 450rpm.

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I got a electronic boost controller that is also a boost gauge. It has a solenoid with an in and an out. I have the in going from the intake manifold and the out going to the actuator. Does this sound correct? I am not getting a boost reading but It could need to be setup. I know Jakeoster mentioned he had a nipple on his Ic piping. Is this my problem? If it is does it need to be right before the throttle body?

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