So about those cams... Good news and bad news.

[Orphan]

VTC just means you can take the cam further without affecting low end performance as much as you would in an engine without VTC, it gives you a bigger window of better opporation.

Not exactly the best example but with the 20 degree VTC it means you should be able to run a 298 cam on the engine you stated but retain the idling and low end performance of a 278. So it just gives you a more usable low end while still being able to have a top end that doesn't run out of breath. Nissans VTC is very old and average compared to VVEL which is what you want.

http://en.wikipedia.org/wiki/VVEL

Its been used on SR20VE's and smaller for quite a number of years now and people are getting over 200rwhp N/A by changing out the cams, exhaust and intake with an ecu tune so thats more than 100hp/L at the engine for bolt on mods which aren't all that expensive.

Can't wait to see how the VK50VE turns out, its rated for 400hp if i remember but should be easy to get another 80-150hp out of it with cams exhaust and tune, so at least a good 400-450rwhp one would hope. If not a fair bit more if the SR20VE is anything to go by.

EDIT: I can't see ITB's smoothing out idle all that much not that I have much experience with them, i thought the main use of ITB's was to let more air into the engine rather than having one or two 60-100mm throttles having 4-8x 50mm throttles has more potential air flow as well as it increases response.

[PanzerAce]

EDIT: I can't see ITB's smoothing out idle all that much not that I have much experience with them, i thought the main use of ITB's was to let more air into the engine rather than having one or two 60-100mm throttles having 4-8x 50mm throttles has more potential air flow as well as it increases response.

ITBs (either fuel injection or carbs) allow you to run a way wilder cam and still be able to idle. Because each cylinder has it's own air supply that it is pumping, you aren't going to get uneven air flow to each cylinder (which can happen when you start going beyond the bounds of reason with a cam). It smooths the idle more by making things the same for each cylinder than any other inherent benefit of a ITB system.

Response and airflow is the big reason for ITBs though. The better idle is just sort of a side benefit to the whole thing.

As for VVEL, I'm not entirely sold on it yet. Yes, 100whp/L NA is good, but then that has been accomplished with thirty year old technology as well (the example I'm thinking of specifically is a 330whp three liter L series engine in a 240Z). It seems to me that it adds complexity and extra stuff that is likely to fail when being wailed on. I notice that BMW, who basically invented it with Valvetronic, and have had a six year head start, have declined to use it on their performance engines, instead using supposedly worse technology.

As further example of why I'm not convinced, lets take the 4.2 FSI engine from Audi and the 4.0 liter S65 BMW engine. Both of these engines make right around the 100whp/L mark STOCK (the Audi is slightly under, the BMW slightly over). While both these engines use variable valve timing systems, neither of them have a variable lift system. Heck, the VR38 only has variable timing on the exhaust, and it's held up as one of the most advanced engines currently produced.

Though, being fair, part of my dislike of it no doubt is that it makes things more complex for those of us that like to do engine work ourselves. I'd be willing to bet that I could build a 100whp/L VK engine without VVEL cheaper than the same thing with VVEL. If Nissan/Toyota/Audi/BMW can pull a high performance engine using VVEL or similar though, all the more power to them.

[Orphan]

Very valid points, I haven't read about any VVEL failures of yet (on sr20veforum) but it definately ads more parts to have something go wrong. 100hp/L isn't too hard on any decently engineered engine but VVEL and similar make it much easier and allow for more road usable power.

As for the do it your selfers the VE system isn't all that complicated, I can grab some pics from SR20VEForum if you would like. Its pretty straight forward, the only real complicated part to it would be tuning but you can always leave it standard or just change the rpm when it actuates for basic tuning.

And the VR38 has turbos so the performance increase from technology like VVL etc doesn't have a very big impact compared to N/A and if you don't have to have it why put more things to break on a performance engine.

I can understand not using it in high performance race engines etc as its just more to break but surely they will come up with a reliable system soon enough? The ferrari F430 engine also makes over 100hp/L out of 4.3L

http://www.cardotcom.com/cars/...2.jpg

Purdy.

One thing to remember about the engines you mentioned is they cost a LOT more than your average engine and have all the work already done. If the VK50VE is anything like the SR20VE I don't see how you could possibly get 100hp/L out of it cheaper if it didn't have VVEL not to mention the better drivability. I'm not being a d!ck I just think VVEL would make it so much easier considering using standard SR16VE N1 cams from a produced engine are what most use as an upgrade to get 100hp/L+ and 4 cil headers don't cost all that much. A few are still using the standard intake and getting good results.

I can't wait to see the first affordable 100hp/L VH. Another thing about VVEL is how many honda Vtec systems have failed? a huge number of their engines feature Vtec and they most certianly use them in racing or for time attack cars. If honda can make a reliable system surely other companies won't be too far off themselves.

I'm not arguing just want to become more informed. One thing that I have wondered about is the VTC vs non VTC VH and which is the better option? I would think the VTC should be fine as its not a constantly adjusting system. If only some of those superstock guys would share some info haha, I think they ditch the VTC or use non VTC engines as its the regulation for superstock but im sure they would have to know at least a little regarding its impact on performance. If 100hp/L is possible from a VH with cams, headers and a tune then it would be a very potent engine, but as said above the stock intake might not be the best for getting that 100hp/L goal.

ALso what L series engine produced 330whp? I'm assuming lots of mods? The L28 only made like 140hp standard and even the turbo was only 180hp. Yes you can make 100hp/L on many engine and have been able to for a long time but the cost is a big factor, its now becoming more affordable. Turbo's are cheap enough why bother spending 6-10k getting the most N/A you can when with a bit of back yard welding and a hair dryer you can just turn a little knob and get 500rwhp.

[PanzerAce]

I should have made myself more clear on the failure point. I'm not saying that they will fail faster than normal, just that when they *do* fail (and all engines will at some point), it adds stuff to have to inspect/fix. Also, the more mechanical parts anything has, the more points of failure there are. That is why Glock pistols are so highly thought of: Gaston Glock cut down to as few parts as possible to make them more reliable.

I'll grant for sure that VVL systems make 100hp/L engines more streetable, since unlike a straight cammed engine, it doesn't have to have huge lift, huge duration all the time.

The VR was a bad example and I'll admit it, I completely forgot that one of the largest functions of VVL tech is to eliminate pumping loss wherever possible.

As for coming up with a reliable system for 100whp/L, I don't foresee any system achieving what a OEM would consider satisfactory reliability on a performance oriented application any time soon. When you consider that BMW has had the tech on the market for 8 years, and probably in the works for twice as long, it leads me to believe that there are some inherent problems with it that are taking awhile to work out (assuming they can be worked out). Obviously, VVL tech is fine for DD and commuter engines, but factory performance? History indicates it won't happen (for awhile, atleast).

Yes, the 4.2FSI, Ferrari engine, and BMW M engines have ALOT of work done to them already, but I think if you added up the cost of buying one of those engines as a turnkey setup vs. buying a VK50VE (or VK45VE in the future as a closer competitor) and building it to the same power level with factory reliability, I think you would find that the difference is in favor of the non VE stuff. I think if you built a NON VE VK engine to 100whp/L with factory reliability, it would probably be about the same price as the 4.2FSI or M engine (Ferrari is in a WHOLE different league though) (I have no actual numbers for this though).

For cheaper power without VVL, I should clarify that that counts buying say a fresh engine block/crank/heads from the OEM. If you already have the engines, then it is quite possible that VVL makes performance cheaper. (my knowledge of SR##VE stuff is non existent, so I can't really comment on any of that).

Honda Vtec I actually like a little more than the current VVL stuff, just because it relies on a second, more agressive cam load rather than levers and the like. As such, not really an apples to apples comparison for it's failure rate. I would expect the same general failure rate from Vtec and normal cam systems.

As for VTC, the more I read up on it, the more I think that it's a good system to have, especially on daily driver cars. It seems to allow for much better idles for a given power, even if you swapped manis for an ITB setup or something similar (though I'd be more than willing to try that some day if I had the money). There is ALOT of potential is the stock VK and VH DE engines, and I'm surprised that there aren't more 100whp/L NA engines out there. Though, as you point out, it's probably because turbos are so easy/common these days.

As for the L series, I don't remember the guy who's running it. I'll try to find it on HybridZ again (it's a good read in general). It is a pretty big mod list, but it isn't something that is out of the realm of a normal garage mechanic. The stock L28s and L28ets are so handicapped that it isn't even funny. The intakes flow terribly, the stock exhaust is a crime against humanity, and the cams are anemic. The 330whp guy is running triple 45mm Weber carbs (a pretty common swap), a much freer flowing exhaust, and a pretty wild cam.

As a price analysis, Rebello Racing (the go to guys for L series stuff), could probably build a 100whp/L L engine for maybe 5k tops.

Speaking of price, that is the real hampering point of VK/VH stuff right now: The lack of aftermarket support. If it had even the level of support that the L series has, much less the KA/SR/LS/SBC engine platforms have, a 100whp/L NA build could probably be done for maybe 4k on top of the price of the engine.

I would love it if you could get some pics of the VE system, since to be honest, the pictures/diagrams I can find with quick google searches aren't very good.

[PanzerAce]

Found the 100whp/L L engine:

http://speedhunters.com/archiv....aspx

Looks like I was only really off on the carbs. 50mm Solexs instead of 45mm Webers. ITBs could probably get that engine to 340whp

[Orphan]

Thats one nice z. Impressive power figures for a 70's/80's 3.1L as well. You have to remember thats aftermarket bottom end, be interesting to see what the standard VH bottom end can do N/A with just bolt on mods, the standard bottom end looks pretty decent to me though different pistons might be worthwhile for N/A applications. I'm keen to see John's results with his 5L ITB set up, I guess that will give us a good idea of what the engine is capable of and what it takes to get there.

[PanzerAce]

Well, yah, the bottom end of the L engine sucks for making power. they're something like 9.3:1 CR on the NA models as well...

Is john using a VK or a VH for his 5L build? I'm interested in seeing how differently they perform (I'm planning my own build as a VK).

Which brings me back to cams. Damn someone needs to come up with some agressive cams for these engines already.

[John Dixon]

I'm using a VH45Have retained the VTC and mine idles nicely with 280deg cams (30/70 70/30) @ 50thou ~1000rpm. They're on grind with the VTC on and 20deg retraded with it off so 60 or 40deg overlap. I'm running ITB's, 12:1CR.Not sure what the factory cam duration is at 50' but I bet its nowhere near 248.

On 4 cyls, 100bhp/l is easily achievable on a 4 valve engine, top race built ones are doing 140bhp/l NA. The 21,000rpm F1 V10's were doing nearly 300bhp/l On a non-flat plane V8 I'd expect you won't get as much as the 4 cyls with exhaust scavenging being worse but if I don't get 100bhp/l out of mine I'll be a bit disappointed

[PanzerAce]

I'll bet you're able to hit 100whp/L.

And race built engines rely more on maximizing intake VE rather than scavenging I think. I'm trying to remember where, but one forum I'm on had a decent discussion on it, with dyno charts and everything, and the general consensus that emerged was that you're only talking about 2-3whp difference between a really well done scavenging system and a system that's the same size assembled without much regard for it. Plus, you could always do the 180 degree setup.

I personally would spend more money on a good intake/ITB setup and polishing up the head than dumping huge money on the exhaust.

[John Dixon]

Engine guys I spoke to said bad header design could knock power 5-10% on anything with more than about 60deg overlap. At lower overlap there's very little difference which would make sense.

[PanzerAce]

Bad header design isn't the same as not dumping huge money on exhaust. Obviously a crap design will cut into power, I'm just saying that I think sometimes people focus *too much* on header design, and ignore other, supporting, mods.

Though given that you're already running ITBs, I'm assuming you've also polished up the heads, so at that point a good exhaust system would be the next step.

[Mettler]

I'm confused... which version of the VH doesn't have VTC? To my knowledge, they all have it. o_O

Yeah they ditch VTC on a superstock due to the rules about having no computer stuff... one team had the VTC hooked up to activate with the shift light, then they just set the shift light to what revs they wanted the VTC to come on at, but that got banned after too.

I'm not arguing just want to become more informed. One thing that I have wondered about is the VTC vs non VTC VH and which is the better option? I would think the VTC should be fine as its not a constantly adjusting system. If only some of those superstock guys would share some info haha, I think they ditch the VTC or use non VTC engines as its the regulation for superstock but im sure they would have to know at least a little regarding its impact on performance. If 100hp/L is possible from a VH with cams, headers and a tune then it would be a very potent engine, but as said above the stock intake might not be the best for getting that 100hp/L goal.

[PanzerAce]

According to wiki, the '96 USDM 45, and all the USDM 41s lack it.

[SuperHatch]

According to wiki, the '96 USDM 45, and all the USDM 41s lack it.

I have a USDM 41 and I'm 95% sure it has it... I think only the USDM 96 VH45 lacked it.

[PanzerAce]

Maybe. I'm just assuming ommission on wiki in this case means that it didn't have it.