r3240sx

Perhaps I'll leave the stock head on and build a head off the car... swap it on one day when its built properly.

Indeed it does, thank you! I always thought the intake manifold was a pretty well flowing design myself, but I figured the reason everyone upgraded these things was not only for convenience and looks, but for less volume. The stock intake manifold is huge! It seems like you'd need a massive amount of airflow to fill that thing quickly. That settles it though, saves me $500-$700! I read that thread, and yes it is very good information. I guess more of my question would be, how much of that is necessary for my application? or should I just follow that advice religiously and not worry? For only 500 rpm over stock redline I'm wondering if this stuff applies to me. I would love to port the hell out of my head, and I most likely will do so if I feel confident enough to do it myself. The cash flow has to stop somewhere! I will most likely be making my own equal length turbo manifold. I might buy a cheap ebay one and just use the design and turn around and sell it once I've made a stronger copy. I believe they flow pretty well, just fit poorly, and are made out of cheap materials.

Machine shop says they need to take 10 thousandths off... But definately fixable.

Notice the end of the oil pump drive

I recently picked up a set of Neo RB25 rods, and a Neo RB25 crankshaft. The motor was out of a friends car, so I got a steal of a deal on the set. The motor failed due to a clogged oil pickup and thus starved the motor of oil and spun a rod bearring. I took the rods and crank to a machine shop, and they told me they could salvage both. The machine shop also told me that they need stock specs of the crank so they can fit rod/main bearrings.... Which brings me to question number 1... 1. Would he be selling me oversized stock bearrings? What is the benefit to using aftermarket bearrings over stock bearrings? I have a goal of 500 rwhp, are the stock bearrings sufficient? My main goal with this motor is to be reliable, and withstand anything I throw at it. I'm not completely sure which turbocharger I'll be using quite yet, but I plan on it being efficient to around 530 rwhp. Realistically I'll never make enough power to max out the turbo, but if I only hit, say, 450 whp, the turbo will make very little heat.. None of this by any means is in a hurry. I plan on buying most of the rest of the parts needed in the beginning of next year, and building a short block outside of the car over the next year. I plan on using the 81.5mm or 82mm 4agze pistons which yields a 2200+ cc displacement correct? Which brings me to question #2 2. On a well sorted 4agze 300+ hp on a stock block is capable (4 cylinder). Will stock 4agze pistons meet my power goals? is it worth the extra money? A set of 6 stockers is about the same cost as a set of 4 aftermarket. I would like to do as many mods as possible that dont put any more stress on the motor, yet add HP. Since money doesnt grow on trees, I'm thinking about doing used GTR camshafts/adjustable pullies, aftermarket intake and exhaust manifolds. 3. Is a knife edged crank worth the cost of machine work? Are GTR camshafts/aftermarket pullies, intake and exhaust manifolds sufficient head flow mods? Should I not bother with the 26 cams, and save for aftermarket? (costly in the states) I want to rev this motor to about 8,000 rpm to give the large turbo a little more room to work with. My main concerns with this is my underpowered oil pump drive, lol! As you'll see on the pics of my crankshaft, there is only about 2-3 mm contacting the oil pump, and its wearing down. I will be ordering a Jun crank collar. 4. Are oil restrictors necessary for my application? is an rb20 or 26 or n1 pump necessary? What other oiling modifications should I do while its all apart? I do not want to do this twice! 5. Where do I get a larger bore aftermarket head gasket? 6. Anything else I'm missing? I really dont want this thread to turn in to an rb20 vs 25 or rb20 vs 30 thread. I live in the states, rb20 motorsets are around $1200, 25's are about $3000, and I've never even seen an rb30. We dont have skylines, so I'm using an s13... which was about $1500 cheaper just in swap parts, than putting in an rb25 in. This website has given me a lot of usefull information, so I just though I'd share my build with the rest of you guys.. Thanks! -Max

Oops! My bad Please delete this one

I'm just curious as to where you guys find the drop in aftermarket cams for a good price... earlier in this thread people seem to think the GTR cams were almost not worth it when you can buy aftermarket for really cheap. What is your idea of really cheap, I have not seen these cams for a reasonable price unless they're used. Then again, I am in the states. Good info guys!

Theres a thread stuck up top with rb20 dyno's, I'm sure you'll find a ton of answers there. With similar mods to you, I made 219 whp 200 tq.

Dont rebuild your engine again unless you have probable cause to do so. I thought I blew a headgasket, turned out to be something totally different... But in the process of diagnosing it I compression tested my motor. At wide open throttle when the motor was cold I got 80/80/80/85/85/80 on my RB20. There is no way I have EVENLY ruined my pistons on every cylinder. You need to look for even numbers, not the right numbers according to your buddies test. If the numbers are all even, chances are you're fine, and if they read low, its either how you're testing, or the guage. If they are dramatically different (ones really low, ones not) then you should be worried. Do the test a few more times. See if the guage will read any higher. Try a different guage. If no changes, then I say dont worry about it.... you seem to be making some decent power, no? With supposedly 80 psi compression in each of my cylinders, my motor has lost no power since it read 150 psi on all.... hmmmm....

The only reason aftermarket BOV's would benefit you is to prevent compressor surge. You can hear compressor surge if you have it. When you build boost, and let off, instead of the BOV compression release noise, its a bunch of short/fast compression releases, one after another... very obvious. I actually think the stock BOV's would be better than aftermarket to prevent compressor surge. I noticed that my stock rb20 BOV was WAY more sensative than my blitz super sound, and now I actually hear a little compressor surge at like 1-2 psi boost.

Hey guys - My first post.. I have a 1991 240sx that I put a rb20det in. I live in the US, but I've been browsing this site recently, as it has some very helpful info. RB20DET- Spearco FMIC 12 psi Stock turbo Stock internals Stock clutch Open downpipe First run was with the stock fuel map, second run is corrected with an SAFC-1 On the same setup with 10 psi boost, I ran a 14.1 @ 98 mph. That was a while ago though. Recently went back to the track with some boost controll issues, new LSD, and 9" slicks. 13.6 @ 103 mph (spun the tires. hitting .4 bar of boost, then slowly climbing to .7 bar) Adjusted the boost controller and hit a 13.6 @ 96 mph. I spiked to 1.1 bar in second gear, that quickly bled to .7 bar... I hooked 3rd gear and had no boost, but a huge splatter mark of oil where my BOV releases.... bummer! Oh well, good ET and poor trap speed. I've got video's if theres interest. I am now workin on fitting a t04e/tial 38mm, 450cc injectors. Goal is 400 hp/300 KW, before I tear into the block for some forged goodness.