Guest Cronic Posted October 6, 2004 Share Posted October 6, 2004 I put down 266whp/324wtq on stock everything, except 3" exhaust, Evo5 intercooler, 2 extra injectors. Stock turbo 16psi (fell from 20psi @ 4050rpm) Peak hp was made at 5050rpm @ 16psi. Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 7, 2004 Share Posted October 7, 2004 Ok, so we know it's fairly easy to put over 300 to the wheels. So why doen't the motor like to get over 500? Is it due to head design? Or something else? It makes me really curious. Now that i think about it, it must be the head. What else is there that could limit the motor so much? You can't say it's the bottom end, the bottom end with forged pistons, rods, crank and such should be able to handle 800hp easy. So our restriction is in our flow of fuel and air. We're talking about pretty big injectors that some of you are using. So what are the stock port sizes? And are there any aftermarket heads? (I know there is that one guy who built his own, but i'm not sure if he's selling them or not) Did nissan make any other inline 6 heads that would be better for boost? (and fit of course) Quote Link to comment Share on other sites More sharing options...
Mack Posted October 7, 2004 Share Posted October 7, 2004 the short answer to all of yoru questions regarding heads is no. nissan never made better heads that will fit, that you should ever be concerned about purchasing. that being said, you can try and track down an LY head. that was a better head that will bolt on to an L series block. there were roughly about 500 of these made and when they change hands, they go for about $20,000 or so, for a head. RB heads will bolt on, but then you have to run seperate oil lines and coolant lines, as well as figure out how to go from a chain drive to a belt drive. The guy that was making a head has not really made any progress from what I gather. This all stemmed from an Idea I had like, 3 yrs ago, because you can put a KA series head on an L series 4 cylinder, and an L6 is basically an L4 with 2 more cylinders added onto it. I do have 2 KA24DE heads and 2 KA24E heads and may pick up the project again, next time someone dumps $1000 into my lap, lol! A company called BC gerolomay (sp?) that did a lot of work with L series heads was able to get 250cfm out of the sideflow head by COMPLETELY reworking the ports. this would probably cost you close to $3000 for a port job of that magnitude, but it would probably be worth it. use that as a starting base, then add a nice T66 turbo and yor getting close to over 500rwhp. McAdam Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 9, 2004 Share Posted October 9, 2004 I think the reason the L28ET doesnt' like to rev much over 5000rpm is more due to the cam design, but also yes inherent to the head design as well. While I dont think I've ever seen this done on a turbo L28, I have seen naturally aspirated ones with extensive head work (porting, polishing, stronger valve springs and lots more) and wild cams that would make power up to or past 7000rpm. I think by this point you need some major work in the block as well, balancing and blueprinting or whatnot, but L28's CAN be made to be high revvers... the problem is that as far I know, doing so always results in an engine that you would not want to drive on the street, because ALL of the power is high up, you're not getting any at low, street driving 2000-3000rpm range. If someone were to go to the trouble and expense of building a really high revving L28 AND build it to withstand the abuse of turbocharging, and with a LOT of money invested, you probably could get more than 500hp out of one, at some point though the block itself, not the pistons or crank but the actual block, would probably give out, and I'm sure that would be WAY before 800hp.... Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted October 11, 2004 Share Posted October 11, 2004 hey Mack, the heads are on hold right now, I've been back in school for about a month and have a lot of homework to do and no time to get back in the shop. I still have them and want to finsih up on them this year but I need to make time for them. Although I have taken a step away from my 24 valve build up I'm porting out a N42 that I came across in a junkyard that will be placed on my z this winter, hopefully I can make some extra power to the z by a light porting/clean up, but only time will tell. http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=30558&highlight= tbs Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 11, 2004 Share Posted October 11, 2004 You really think the block would give out before you hit 800HP? Even if you have the proper sleaving done? This would proove that it really was a poorly designed engine. Look at other inline 6 motors. Supra blocks are capable of well over 1000hp, and i've seen a couple of skyline motors over 1000hp as track only cars. Same block, just extensivlly reinforced with sleaving. I guess it is a pretty skinny block. But still, i would still think all the limits you hit are in the head. To me though there should be no reason you can't just sleave, blueprint, balance the block, put in a forged steel crank, pistons, rods, ported the head, put in a really nice custom valve train, and put in a turbo putting out 40+ psi and then just see what HP you hit. It obviouslly wouldn't be safe if the head limits your flow, but i'd i imagine the block & bottom end would be fine. I've been amazed with what some people have done with stock blocks. I know a guy from another forum that got into the 9's with a 03' cobra with a stock bottom end. And he even got into somewhere around 9.6 before he started messing with the bottom end. Now he runs 8's with a fully build 03 cobra that he drives on the street. And i'd bet that the block would withstand running 7's, but there is just too much work to get an engine that small to that level, you're starting to hit the same HP per cubic inch as funny cars. Anyways, this is just my 02 cents. I really think it would be sad if the block itself couldn't withstand more than 600hp at least. But then again, my standards seem too high in this respect. I should just look to a different motor for REAL performance. Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted October 11, 2004 Share Posted October 11, 2004 If I remember correctly the L6 was copied or at least modeled after a Mercedes L6 engine that was dreamed up way back in mid to late 60's. Someone correct me if I'm wrong. Also after about 10 years of track testing Nissan knew that the L6 block wouldn't hold up to extreme horsepower that they wanted for future cars. So the L6 was put to rest. From its ashes the FJ20 was possible, from there Nissan designed the RB30, CA18, RB20, RB26, SR20, ect... I do believe that the F54 L6 block is a strong block if sonic testing check out. Also the L6 blocks are very wear resistant thanks to the high nickel content of the Iron used in production. tbs Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted October 12, 2004 Share Posted October 12, 2004 I have NO idea just how much reinforcing of an L28 block you have to do to get it to handle that kind of power, or if it's even possible (well... just about anythings possible). As turbobluestreak says though... you're kinda comparing apples to oranges when you compare the skyline and supra blocks to the 30+ year old design of the L6. Really what it boils down to is if you really wanted to build a motor that could handle that much HP you're better off saving a lot of time work and money and just throwing a supra or skyline engine into your Z to begin with, since most of that engine reinforcing would already be done for you Maybe that's why no one has really bothered to do it. Just out of curiousity, Paul Newman used to run a race 280zx with an L28ET in it didn't he? Or was he running the V6 or that V8? Surely someone has raced an L28ET powered car... what kind of power were they making? Quote Link to comment Share on other sites More sharing options...
turbobluestreak Posted October 12, 2004 Share Posted October 12, 2004 Bastaad525 go to http://www.rebelloracing.com and call them up and I belive talk to dave. and he'll tell you anything you want to know about the old days. When I talked to him the turbo z that was raced back in the day was a L6 the most powerfull US L6 if I remember and the head was ported by a guy in a very small shop with no flow testing equipment. After the head was ported the racing team turned it over to dave at rebello and to his suprise the head was almost perfect when it came to them some clean up and bam the head was ready for race. If I had the money these guys are the only people I would personally fully trust to work on my L6, they have the experience,ties with Nissmo,and proven set ups to make screaming z's tbs Quote Link to comment Share on other sites More sharing options...
Mack Posted October 12, 2004 Share Posted October 12, 2004 I think the porblem lies not within the block, but in the head. The cylinder walls, even when bored out to 89mm for a 3.1L are still thicker than a stock VG30DETT's cylinder walls. also, the L series is a deep skirt design, which lends itsself well to having the bearing caps stay put on high HP applications. I think the weak link, once you get past the head, will end up being everything else, lol! for ultra high HP, you'll need forged pistons, forged H-Beam rods, and probably a custom crank. with full counterweights. adn if you wanna get crazy, have a girdle made for the bearing caps, but the supra boys run without one and they also have a deep skirt design block. McAdam p.s. TBS... any progress on that head?> do you stilll have the 3 halves? I may be interested, have a line on an awesome heli-arc welder in AZ. EDIT: Don devandorf and electramotive raced a 280ZX twin turbo back in '82 that developed almost 600rwhp. here is the link to some info on the car.[/url] Quote Link to comment Share on other sites More sharing options...
Gollum Posted October 14, 2004 Share Posted October 14, 2004 Woa, that rebelloracing company is within driving distance to my house with ease. I should call them up and see what work they could do to my ZX. Yes, i know that the head is the main problem. This is what i was stating earlier. I belive almost any block is easily capable of handling 800+hp. Blocks can be extremelly resilliant with the proper sleaving. Now, i believe the stock head desgin is basically crap. This is due to it's ancient design. Some may argue about how "all those old motors had tons of HP", well the 6 cylinder in the mustangs in the 60's had less than 100 hp. So there. And 302s rarelly got more than 350 hp. That's just a little more than 1hp per CI, and now we have cars like the S2000 that gets 1.4 hp perCI (the older 2.0 model, i believe the new model is underrated. How do you keep the same HP & tourque numbers when adding .2 liters?). Now days you can get a 302 over 400hp with ease. This is because of modern technology. The old 427 drag cars had very little more HP than the stock cars. Now days it's very different. The new cobras run better than any mustang of the past. And it's a small engine( 4.6). The same thing applies to our z cars. It's an old engine and it's not going to REALLY made HP unless you modernize it yourself, or buy aftermarket tech for it. Unfortuatlly the Z market isn't poplular enough to support large amounts of support when it comes to swapping out heads. Maybe in the future we'll see a larger number of z car people and in turn more demand for performance parts, resulting in more new tech for our old cars. Sorry if that draged a little. Quote Link to comment Share on other sites More sharing options...
zbuild Posted October 15, 2004 Share Posted October 15, 2004 I run around with mine on 15psi (308rwhp) and have had it screwed up to 17psi (370rwhp). . . .I think 800hp in a Z would be darn scary ! I get plenty of sideways action with mine now Ive been away from here for a while my z's details can be seen here: http://www.240z.id.au cheers Quote Link to comment Share on other sites More sharing options...
Guest bastaad525 Posted November 1, 2004 Share Posted November 1, 2004 Well... Until now, I had thought that 450rwhp was pretty much the upper limit of what has/could be run on an L28ET, modified block/head or not, but there seems to be at least some evidence that guys are getting significantly more, and the L28ET is not as 'limited' as I thought: http://hybridz.org/nuke/index.php?name=PNphpBB2&file=viewtopic&t=38041 Quote Link to comment Share on other sites More sharing options...
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