thehelix112

This thread is almost 5 years old. Shop has probably been and gone. Dave

Holy jesus. Dave

New bore means new piston rings. Should be a tidy little engine once shes done. I look forward to coming along to the dyno. Dave

I love that compressor. Has usable efficiency up to 3.5bar, and can still flow almost 100lb/min. Going to be running NOS? Dave

Whats the exact specs on that turbo? And when do you expect it to reach full boost? Oh, and nice manifold. Dave

Personally, I would prefer a well-built N/A, to a half-assed/dodgey built turbo. Dave

Watching a stock GTR is like watching fat people f*ck. Kinda interesting from an academic point of view, but would be much more entertaining after they get some liposuction, and coke. Dave

Paul, I agree with everything you said. We do want the entire profile information, and everything is a compromise (area under the curve vs wear). I wasn't aware that advertised duration referred to anything other than the point at which the valve starts to lift at all. That changes my view of things if it is true. The more information you can get out of the cam manufacturers, the better, and the more informed your decision can be. Thanks for more succinctly and completely making my point. Dave

Tony, Perhaps my statement over-emphasized the importance of 0.05 duration. Don't get me wrong, I still consider it a much better indication of the characteristics of a cam that advertised duration, but, what we are really trying to do is to deduce some information about the entire cam profile. Ie, we are trying to understand the ramp rate, be it asymmetric (between exhaust/intake I assume you are referring?) or not. I don't understand your point about the numbers at 0.05 being useless because Nissan grind their cams with assymetric ramp rates. What difference does that make when considering an aftermarket cam manufacturered by person X? More to follow, should do some work. Oh and those racer brown articles look very interesting. Dave

Thank you. That sounds like a nice cam to me. Interesting that he cut down on overall duration. In order to get an adequate 0.05, this then requires a relatively high ramp rate, and also limits the maximum lift you get. I think.. I am still learning about cams. I'm not sure why you would do this instead of increasing the advertised duration, and reducing the ramp rate, and getting more lift. Or am I incorrect in my assumption that a lesser change between adv and 0.05 means a lower ramp rate overall? Dave

One day, ooone day, someone will post the specs that actually have any mean whatsoever for a cam. That is, the 0.05" duration. For example, the cam I am running right now, has 295/292 duration, but is WAY too small, and will make max power maybe 100-200rpm higher than stock. Why is this? Because the 0.05" duration is only 212/210. Check this link for examples of why advertised duration means nothing. http://www.crowcams.com.au/templates/Catalogue-Datsun-OHC.shtml Dave

Do you consider Nissan gaskets to be cheap? Dave

What is the 0.05 duration? I'm guessing not too big if the adv is 260? Dave

225CFM.. thats getting up there. I am by no means an expert, but that sounds awfully high for how much hasn't been done to those intake ports. Is that measured without valves or with? And at what lift? Dave

Lets not judge too harshly. I know I have had the odd stuck throttle here and there. Dave

Thanks. Dave

JohnC, Not sure right at the moment, have the equations in a book at home. Unless your question was rhetorical, in which case I won't bother. If I'm interpretting you correctly, you're essentially saying why worry about it? I would say most people could ask the same question of knife-edging at all. My thoughts were simply if you are going to do it, why not do it properly? I was also wondering, and this would seem a no brainer but I just want to check, any weight that you take out of the counterweight really should be taken out of the rod/piston assembly on the other side yes? If so, then you really should get the rod/pistons before you give the crank to the machinist and tell them how much to take out. Although, with the LD crank, I have heard that the LD rods it was designed to run with are less than petite. Did you measure the difference between those rods/pistons and what you were running? Also, what balancer did the ROD run? Thanks, Dave PS. SOrry for the hijack.

I don't understand why you would compromise given the amount of effort you have put into the rest of the car Stony. Motec has THE best after market engine management system available IMHO. Discounting the big boys of course (Bosch, Delco etc). Dave

Motec M600 FTW. Dave

I don't really think its a joke. At 45mm from the crank centreline, the throw/counterweight is doing about 100kph at 6000rpm. Thats more than enough airspeed to create enough longitudinal force to slide the crank fowards or backwards I think? Dave

I am appropriately humbled. I haven't heard of that referred to as a GT2860R5, though it makes sense to distinguish it from the 707160-7. Dave

Tim/John, Thanks for the replies, will post some more in depth thoughts later, but for now. Very good point about lift, I was planning on a symmetrical design as Tim mentions. Tim, I when I say end, I was not referring to leading/trailing edge, but more the outer extremity of the counterweight (where its airspeed is the fastest). Excellent point about the `ground effects' when the counterweight is spinning past the throw/rods, but lets not also forget the effects when the counterweight is spinning past the main towers. I would suggest that this effect would be cancelled side to side? As we always have two throws/counterweights in the same position, and each side of the weight/throw will be symmetrical and hence undergoing the same ground effects but on opposite sides. Or have I forgotten something? Dave

And I assume you mean 2860RS's, not ``2860R5's''.. or do you just see the pen and the chequebook? Dave

The problem as I understand it with VATN turbochargers is that they were desigend to run in diesel engines. Diesel burns MUCH colder than petrol. On petrol engines I believe they have issues with longevity/reliability. Heresay though, so don't take my word for it. I did read though that Porsche have spent a lot of time/money on the superalloy for their adjustable vane turbochargers in the new 911 turbo. Dave

I often wondered how on earth james' spacer held up, but that does answer some questions. Look forward to hearing about the results. Dave