Yes Danster I agree it may flow on a flowbench more OK. But flow is not always result more power or best burn or best torque profile. I based these engines quite loosely on an engine with a similar torque profile. My 3A thing engine was thrown in there as minimum "worst" case baseline. This is not a 16v vs 8v thread.
That is fine, Once you understand the limitations of what you are dealing with then thats cool. Do it right and you will have a strong pulling engine.
am i allowed to say 20 valves lol my next project will be 8v crossflow on megasquirt so interesting to see whats being said
You are not allowed to state more than 8 ventils on this thread apparently. Else headteacher dan will whip you lol!!
Yea I know your never going to get 16v power out of an 8v that's just a given the fact there's half the amount of valves. I'm not chasing numbers like most people are with valvers, always throwing around the 200bhp figure when talking about a 16v. Were just trying to determine if the Crossflow has advantages over counterflow and if that advantage is enough to outlay some cash for it. No ones really going to want to shell out 500 notes for a 2-3hp gain. The main limit with 8v tuning is money and experience, there's a JRE built 8v for sale at the mo running 212bhp, that's more than alot of valvers out there....it just would cost more to get there with the 8v.
danster you need to print and frame that doesnt happen much toyotec is now on the tequilla and icicles
Only on some points. That is all I am correcting. You have done it to me in the past, so no hard feelings. This is nothing to do with winning anything. We all want to accomplish good things on here as it is a good group of folks covering a broad spectrum of interests. We all have different, skills, strengths and weaknesses. It would be far more beneficial for all if these traits could be directed in a more positive way to helping out folk when needed.
Dont get me wrong I am interested to see the achievements and potential of the 8v crossflow but feel the per BHP will be more than other engine choices out there. To justify my post, I have had many 8v's in various forms of tune, one I spent alot of money on - and gained little. I bought a GTi eng car with big valve head and schrick cam, it drove well etc but I wanted/expected more from it (i was also running a 2E ported head in another mk2 that pulled harder lower down). I had a problem with the BVH head and had to have new exhuast valves and a seat - which cost lots . At the same time I bought a S/H 1.9L bottom end - cheap. It was running digi so i took it to Stealth for mapping and ended up with 139bhp and 138Lbft. The cheapo 2E build felt just as good as the expensive 1.9L build but did not rev as well. 2.0L PP head cost around 550 in parts to put together. The 1.9L 8v BVH schrick cam, mapping etc etc cost me over 1400. My standard 16v bottom end ported head MS and ITB's has cost me less than the 1.9L 8v build and that includes the mapping! 16v 163LBFT for the win. This was my experiance and what i would like everyon to take from it is 8v are great engines and can feel really pokey, the most I would do with one is 2.0L bottom end, ported head, mild cam and remap. Once you start adding bigger valves the pound to BHP ratio is not cost effective and a ABF on digi is the way to go - and yes I have one of these. Standard engine and ECU put into a MK1, cost was sub 500 for dono MK3 which i made quite a bit back from selling off parts. Modded the wiring loom so i could fit MK3 fuse box, diagnostic port, clocks, MFA etc etc. Took me about 3 weeks to fit but I also buggered around changing loads of other parts and painting the bay etc. And this ABF will out perform all the 8v's i have owned - mind it is in the MK1 chassis. Mine were all counter flow heads so it may be a different story with the cross flow but im not holding my breath. Please someone make a optimised 8v counterflow to show use the way. please see my 8v build here that inlcudes a 1.9L and a 2.0L. And to conclude I beleive it is cheaper to fit an ABF for sub 500 + manifold - cost of selling off bits, than to try to achieve similar BHP from the counterflow 8v. But just fitting the counterflow head and hoping will not get you very far either, the car will need either mapping (digi) or the WUR mod and a good setup + head bolts gaskets . But to start to gain ABF power you will need a cam and head work/valves and maps/tunning . VR6 will mean chassis work + exhuast and a 20v will need engine mounts + manifold So what do you want to pay? as there are expensive ways or cheaper ways to the desired BHP.
So this 163 lb/ft is on the standard ECU then yea? wouldnt happen to be on those throttle bodies you got on there now would it? and possibly extras! its not 500 for a 163 lbft ABF is it, its more like toyotecs graph of 150bhp and 140 lb/ft aslong as you get a good one that is still producing this kind of power with out having to take it apart. I will say it again........i realise that i am not getting the most bhp per using an 8v but its what ive got (AT THE MINUTE doesnt mean i cant move on to some thing different like you did smudge ) so im going to try and make the most out of it. Im also not just going to be fitting the counterflow head on its own, i can use the 285 cam ive already got, raise the comp to around 11.25:1 to get some good bang with just a skim and get some P&P work done, which is cheaper on an 8v. Then its running on twin carbs and is due a MR H masterclass in the new year any ways. This lot may cost a few more than getting 160 lb/ft from an ABF but i dont rekon that 160 figure is going to be far out from what i will get out of the 8v once finished.
Please read my post again I said it cost less than 1400 or the price of 138lbft 8 v power I now see all my 8v developments as a waste of money and would recommend people do it differently. They may be fun but they have limits and are exspensive. 160lbft from standard 8v. Looking forward to your dyno plot then. I would say you should expect a lot less than that with your planned setup.
1,175 + head bolts + head gasket + bottom end (price unkown) + carbs (price unkown) + cam (price unkown) = far to much money to spend on an 8v that will/may give less then 160lbft. You can drop in an ABF on Digi for 500 for dono car - selling of dono car parts + exhuast header. Or if you want more power (as above) but have the Digi ECU remapped and be very close to 160LBFT. Or as I have make manfold ITB's add MS all for less than a 1400 138LBFT 8v . Or add a 20V. Or leave the bugger alone and see how a counterflow will perform with some (cheap) porting. and CARBS dont even get me started, ECU every time otherwise you will never get the most from the engine and you will be tempted to go that route at some point in the future with all the added expense... Im not trying to bohoo 8v's but they cost so much when you try chasing standard ABF numbers, my friend is ditching his 2.0L cam'ed BVH 8v in favour of a 2.0L 16v - he like me built his 8v over a number of years but after driving it a handful of times after he finished it he wants to change - might have something to do with driving my valver but there we go. and he doesn't think it is much if anything more than his old STD KR engine. If you have the money to burn do it, then change it if you need. But with most people 1400 + the rest is a lot of money. But then it begs the question why ask if it is worth it when start to mention 16v's in your initial post...as you could have something like Gurd's STD ABF header and tunned, 160+LBFT on plenum...
They only cost so much if you go about it a certain way. There are other ways of doing things that accomplish a similar end result. The crossflow head is a different ball game in terms of flow compared to your counterflow head Smudge. You spent money getting your 8v head ported and fitted bigger valves to do what ? Improve the flow characteristics of the head presumably. Well the initial test have shown that the virtually std crossflow inlet port flows the same as a fully ported counterflow head. Therefore all the money you spent on the head is potentially not needing to be spent on the crossflow. GeorgeHH's simple and cheap build running on Digiphant has produced decent results. Zippy748s has unresolved issues, VRWill's was compromised on compression. Spending money on the wrong things does not reap rewards in certain circumstances.
I agree that the crossflow does offer greater flow and i am really excited to see it achieve its potential at a sensible cost. BUT the figures being talked about here are massive and he wants to go with bigger valves, what do you think of that? is it WORTH IT? (as the post asks) Thats my point here, anyway, every knows im 16v FTW so ill jog on...
Yea I totally get you point smudge, I've gone away from the route I was going to in that quote it's not going to cost any where near that 1400 mark which I why I started the whole thread in the first place. I didnt want to be spending that kind of mega money to get little performance. I just want to use what I've got for now. I like my 8v and for now I want to stick with it, I know damn sure I will end up going for another engine with more power in the future, but for now I'm just goina be ignorant and stick with the lesser valve option The thread is not a is it worth it against a 16v conversion, it's is it worth it compared to counterflow. Hence the post in the 8v section!!
There is no need to jog on. It is interesting to see others views. Was your 8v ecu fully mappable to get the best from it? Apparently a certain race series runs 2.0 bottom ends, 11.2 : 1 comp, 300deg hydro cam, std valves and unported crossflow head and inlet plenum / TB, with a chip, and these make approx 155 / 160 lbft and 160 / 165 bhp.
Saying that the figures are "massive" is a bit over the top, im no longer going big valves as it has pretty much been agreed that bigger valves are not worth the extra money and will most likely cause more hastle than gain due to the amount of shrouding which is likely to occur. I think this thread just needs to be abandoned until some 1 comletes a decent spec worked crossflow 8v (how ever much of a "waste" of money it is) and posts some graphs and figures up.
