Le fun has begun..

[JTR32gtst]

In my intro thread I posted how I had lost compression in the front cylinder and rear cylinder. I have chalked it up to too much boost for the stock, yes stock, intake manifold to handle. Readings were: 60/125/125/125/125/40. I have a feeling years of a poor tune due to failing ECU (had lean spots throughout and never could get rid of them) attributed to its ultimate demise. Luckily, it the wee RB20 did not decide it needed its own ventilation and the internals are as assumed ok, minus the thought of burnt rings in two cylinders.

Last year was a bad year with failed ECU requiring a brand new standalone, then it got rear ended, then it went boom boom, so for the last 5 months, she has been sitting. This past weekend, me and a buddy decided to yank the wee one and I would start the rebuild process. He took the driver side, I took the front to exhaust side and 5 hours later, bam, empty engine bay.

Plans are as follows:

CP forged custom pistons
ACL bearings throughout (main/rod so on)
Metal headgasket
1 mm over sized valves/springs
port/polish head
740 cc inj (brand not yet known)
New intercooler custom made from engine builder/piping
new intake manifold (looking at the GodSpeed or eGay, depends on reviews as I research)
new gaskets/seals throughout.

I already have cams/coil packs/pump/ecu/turbo/exhaust mani/fuel pump and so forth so it is basically just a rebuild. The only problem is by Feb 25 me and my wife will have a brand new baby boy, our first, so this project is not one to end quickly. I am just looking forward to wrenching on my car finally. The only things shop built will be the head/block and intake mani with piping. Everything else will be done by me and a friend in my garage. Here are some pics for your enjoyment.



She sits in her room. It is a 3 car garage with a seperated wall with a sink and running hot/cold water with Nissan color coding. Yes, I am a dork, I know.


Coming apart. Everything went very smooth.


How the wee one sits now with the tiny looking T3/T04E turbo. hard to believe she made 390 rwhp with poor compression and bad tunning. RB20's and RB's in general are stout little motors.

I will keep everyone updated if you like. Thanks for viewing.


Oh, all my Skyline friends call me Baby20...feel free also.

[NolimitZ32]

Nice, very nice, I am guessing you are in Canadia right?

[Jmoore124]

I don't understand how you losing compression has anything to do with your intake manifold not being able to handle the boost you are running?

[WDRacing]

I was putting 28 psi, via a TO4E, through the stock intake manifold with no issues. Also, the intake manifold isn't going to cause a loss in compression. More likely you have busted ring lands or cracked rings.

The RB20 loves alcohol injection btw...loves it.

[JTR32gtst]

Ok, you guys seemed to have taken my post too literal and neglected to read further...

Let me go deeper: I suspect the stock intake manifold did not properly disperse the air evenly causing lean conditions in cylinder 1 and 6 burning up the rings and causing low compression. The overall low compression is due to a failed ECU that leaned out at 4,000 RPM and was never able to proper get tuned out therefore I suspect weakened the motor over time. I do not doubt I have bad rings, hence the forged pistons replacing the stock equipment.

Hope that clarifies..

[Jmoore124]

Read the entire post and I understand what you are trying to say. I just don't buy that your intake manifold contributed to a lean condition in two cylinders. That would insinuate that due to the manifold design the cylinders were not able to get proper airflow. Airflow just doesn't work like that.
Just talking, not arguing.

Keep us updated on your progress, good luck with the build.

[WDRacing]

Where the manifold is concerned, if anything would be an issue, it would be a restriction. This restriction would cause an overly rich condition, not a lean one. The manifold isn't going to cause more air to enter the #1 and #6, especially under boost.

For the record, the RB20 intake manifold is a pretty good design. Nice long runners for low end torque, much needed on a 2 liter motor.

A bad tune will cause detonation, that's definitely not a good thing.

[JTR32gtst]

So I had it backwards. You get the idea. The runners are great, but I assumed with the small throttle body and the non tapered design , it was a restriction. That is the word I was looking for.

I think you guys understand what I was saying, I just did not use your wording. I have heard that the manifold was only good for 350 hp. Now, I understand that means literally nothing, but no one that I know, aside from 240 guys has ever pushed an RB20. I did. I also stated in my post, both actually, that I also suspect a poor ECU and years of poor tuning to help. I also suspect my intercooler (not stock) is also a slight restriction. Years ago, I was forced into a turbo upgrade and being how we were financially strapped, I did a budget build and the shop that helped was very shady. I'm still finding errors they did to this day and cleaning it up. They had no vacuum line that ran from the turbo to the boost controller. It was open..... That is just an example of how bad it was. I do not doubt it was poor tuning that was the ultimate demise, I just suspected the intake, not runners, was a restriction also.

That us why I like the GodSpeed manifold, I still uses the stock runners, I am just trying to do research on it to see if the reviews are good. I'm building this one right this go around.