Mikelly Posted November 15, 2000 Share Posted November 15, 2000 ...and some very REAL numbers a guy just posted on his new dyno'ed 3.1 stroker build... Sobering statistics really... 175 RWHP doesn't seem worth the investment and work involved with building up a stroker at this point. The way the post read, seems the owner wasn't real happy with his results or the fact that he won't see a huge gain even if he makes some changes... Check it out, it was worth reading... Mike ------------------ "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
Guest Fast Frog Posted November 15, 2000 Share Posted November 15, 2000 Mikelly: I did a post as a reply to that 3.1 Liter topic on zcar.com. We might get some response-I wasn't very "flowerery" but, hopefully not antagonistic. Rick Quote Link to comment Share on other sites More sharing options...
Drax240z Posted November 15, 2000 Share Posted November 15, 2000 Well surely from the info I have found around on the 3.1L, in general I have heard it just isn't worth the cash. If you want high performance out of the I-6, stick with 2.8 and spend the $2000 on stroker stuff on headwork. I realize that swapping engines isn't that big a deal (though it snowballs) but I really think the L28 can make that car FAST. Some people want more than just FAST, so we are here. Talked to a guy that has a 240z with a dyno'd 220rwhp, in a 1900lb car. Strictly auctocross. I have little doubt that this car is fast enough for 80% of the Z population. What I am trying to get at, is that a NA L28 isn't a terrible thing, and for most people its enough to keep them happy. Lets let them play in their sandbox (zcar.com) while we play in ours. (I just fear some of them coming over here with bad intentions, and I don't think we need to provoke them) ------------------ "Gimme Fuel, Gimme Fire, Gimme that which I desire" -Metallica Drax240z 1972 240z - L28TURBO transplant on the way! http://members.xoom.com/r_lewis/datsun.html Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 15, 2000 Author Share Posted November 15, 2000 It has nothing to do with playing in sandboxes, what I thought strange was the numbers.. Remember, for years (More than 10) I built L series motors to go as fast as possible, and I was also almost drawn into the stroker ranks... Reason I mentioned the post was strictly an FYI for those considering it an option... Mike ------------------ "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
Drax240z Posted November 16, 2000 Share Posted November 16, 2000 Sorry Mike, my post was a bit ambiguous. I was more or less referring to Fast Frog's comment that we "might get some response" I welcome positive feedback from anyone! But I fear that its negative that fast frog was referring to. Either way, it does't matter. I must admit I was a bit shocked on how low those numbers were myself, especially running DCOE 45's... But the guy didn't really post a lot of info on his engine itself, so maybe he still has a lot of room for improvement with it. I read a post over on zcar about a guy that seemed to know his car well, and said he's run 12.2 with the L28 (2.8) and triple 45's, which sounded sincere and truthful from him when I read it. Those numbers in a 2500lbs car would mean 276 flywheel hp. Assuming 18% loss, that is still a respectable 226rwhp. This makes me think that the recent 175rwhp engine was not fully tweaked. I think if there is a lesson out of all this, its that the 3.1 route can be benefitial still, but that its a "end of the line" improvement. ie: one that you make after you have allready squeezed out all the power you can from a 2.8. There is no "magic" that occurs by going to 3.1L. (which I know most of you guys know, but it seems that there still are myths surrounding the 3.1L stroker) Not trying to step on any toes. Please don't take it like that. ------------------ "Gimme Fuel, Gimme Fire, Gimme that which I desire" -Metallica Drax240z 1972 240z - L28TURBO transplant on the way! http://members.xoom.com/r_lewis/datsun.html Quote Link to comment Share on other sites More sharing options...
BLKMGK Posted November 16, 2000 Share Posted November 16, 2000 Hey, likewise there's no magic in stroking a SBC either. You'll pick up SOME HP and most of all SOME torque but it's not th ebe all end all. Th eonly reason why I chose to do it was because the cost was nearly the same for a good 350 build up. Unfortunatly the 3.1L L6 isn't quite that simple. 175HP does sound low, surely there's some room for improvement. Perhaps his compression is low? Timing curve? Poorly ported head? Could be any number of things. Mike and I both know someone that's got a BIG motor that didn't make the power it should have - it's all in the combo and getting it right. For that matter my 351W hasn't moved recently either (sigh). Quote Link to comment Share on other sites More sharing options...
randy 77zt Posted November 16, 2000 Share Posted November 16, 2000 some times certain combinations of parts dont work out and you dont now till dyno day after you spent all of your money and some on the visa too.it happens to every body once or twice.this is called learning by your own wallet.best thing to do with a motor is copy some body elses if it pulled big dyno numbers. Quote Link to comment Share on other sites More sharing options...
Evan Purple240zt Posted November 16, 2000 Share Posted November 16, 2000 Hey Drax, what do you mean by play in thier sandbox? You spent alot of time at zcar.com and it is still a good site. You have to remember that it is more of a newbie style site. I almost swapped over to tripple webbers looking for that last 1hp but i got smart and did a turbo conversion. Some people might be happy with the stroker, some not. To each his own. Sorry if this seems flamish, i dont mean it that way. These are two sites, with two completely different mindframes! Evan Quote Link to comment Share on other sites More sharing options...
Drax240z Posted November 16, 2000 Share Posted November 16, 2000 Well, what I was trying to get across was that I didn't want to offend people over at zcar.com and have them coming over here to look for (or make) trouble. IMHO neither site will benefit from being "at war" with the other. I've spent years on zcar.com and I still go there every day. I much prefer what I read here, but maybe that's just me. I don't go to zcar.com to flame people, I go there to learn every last bit I can about datsuns. Personally I like the diversity of knowledge that frequenting both sites gives me. I'm not saying that being on 1 site should exclude the other, anything but! I just think that we would be wise not to furthur the animosity between the two sites. Back to the topic at hand. I think you guys have hit it bang on about the "right" combo. I mean if the guy there is running 45mm webers without using a HOT cam, header, high compression, etc he's really not going to get those huge numbers. Not to mention about a bazillion things that could be wrong. (weak spark, wrong jets, vacuum leak, etc) I wouldn't mind running a hot L28 triple setup in a 240z one day for autocrossing/track... ------------------ "Gimme Fuel, Gimme Fire, Gimme that which I desire" -Metallica Drax240z 1972 240z - L28TURBO transplant on the way! http://members.xoom.com/r_lewis/datsun.html Quote Link to comment Share on other sites More sharing options...
Dan Baldwin Posted November 16, 2000 Share Posted November 16, 2000 Originally posted by Mikelly:...and some very REAL numbers a guy just posted on his new dyno'ed 3.1 stroker build... Sobering statistics really... 175 RWHP This isn't surprising to me, based on my impressions of the 3.1 in my '71. Still, it is a VERY worthwhile thing to do, especially for a street/track car. With a stock N42 head(~10.2:1 compression, stock cam, and stock SU carbs, mine put out a TON of low-end torque, great for a street car and great for squirting out of corners at the track. Found myself shifting out of 4th at ~5500, though. But that's really only an issue at the track. With a 290/.503" cam, I was able to shift from 4th at 6000, a big improvement, but still an issue with a tall .745:1 5th ratio. Now I've installed 2" SUs, and breathing is of course improved, it's still pulling in 4th at 6250 (didn't have to go to 5th at Mosport). Next on the agenda is headwork, followed by 45mm Webers. I've no doubt that the engine can be made to breathe well at 6500+. But even with stock cam, head, carbs, the engine can't be beat as a cheap, direct-install street torque-monster. Getting high-rpm capability requires some additional work and money, though. Dan Baldwin '71 240Z 3.1 COMSCC #7 SPB Quote Link to comment Share on other sites More sharing options...
John Scott Posted November 16, 2000 Share Posted November 16, 2000 Satisfaction for some of us is not always going to be maximum hp. I think its obvious who is going to win the power wars. The L6 fanatics have their reasons for sticking with them. They were one of the coolest cars on the road when they first came out. Many just want to stick to the same platform. A previous post was making some pretty big hp claims for the 3.1. The post Mike was referring to may or may not be typical results, but is probably at least in the ballpark for a street going 3.1. JS Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 17, 2000 Author Share Posted November 17, 2000 Well honestly my intention here was not to get everyone's dander up. I know there are those that do and those that don't prefer an L6, and that is fine, if everyone were like me, life would be pretty bland. I knew that this topic had recently surfaced on this site less than a month ago, and I personally found the info of interest because I had done some research on stroker L6 motors a few years back and I found the guys data of interest to note here. Last thing I want is an US vs. THEM war with any of the ZCAR sites so if I mislead anyone, sorry for that. Mike ------------------ "I will not be a spectator in the sport of life!" mjk Quote Link to comment Share on other sites More sharing options...
pparaska Posted November 20, 2000 Share Posted November 20, 2000 It sure seemed to me that the guy that posted about his stroker not putting out power you would expect even from a well built 2.8 meant it wasn't tuned or set up correctly. There does seem to be some kind of mythical thing on Zcar.com about the 3.1L being some incredible leap in performance over a 2.8. We all know that if they were built with the same level of preparation and correct parts matching, that the 3.1 would run by a factor of (3.1/2.8) better than the 2.8. There is no magic. In fact, the rod to stroke ratio could actually be seen as less benificial for a high rpm motor if you used the 2.8 rods in the 3.1L. That said, I was down in Huntsville this week and met up with Morgan. I'll tell ya, the sound of a lopey L6 and then as it revs throught the gears is very tantalizing ... It brought back fond memories of my L6 days. Sweet little motor it is. And no, that little isn't necessarily derogatory either. Some of us like REAL tons of torque, only available from boost or LARGE increases in displacement. You end up with a different car though, and one that may not be for everyone. ------------------ Pete Paraska - 73 540Z - Marathon Z Project - pparaska@home.com">pparaska@home.com - Quote Link to comment Share on other sites More sharing options...
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