Agreed:thumbsup:Quote:
Originally Posted by tinkerbell
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Agreed:thumbsup:Quote:
Originally Posted by tinkerbell
I hate this time out thing with posts ARGH! Just lost a massive reply. Skinny of it is this.
I'm listening to you, I am. Your advice is basically don't get the head until I build the bottom end. And then if I do build the bottom end, increase displacement to 2L. There is no middle ground.
Based on the prediction by TB that power is likely to be more like 130kw with the head in comparison 121kw as it is now with stock bottom end, it is likely more benefical then to get some ITB's (I still can't believe I'd only see a 9kw gain out of a ported head and aggressive cams). Some of you agreed to this (buying ITB's instead).
My point is, since I will have to buy a head at some stage for the new build, and the fact that I can use the same head on the current motor and then on the built motor, how is the logic to buying this different to buying ITB's (which I can also use on a new motor)?
TB -- Since my car outputted 106kW with IHE un-tuned, and 107kW on a different dyno, I am assuming that both of these dynos were calibrated / corrected (somewhat) as this is also the output reported as normal for mods by many others. The power figure you claimed for Toda B being 120kW is surely therefore a low-reading? And how on earth can I then give you my goals if those goals depend on the dyno I go to? i.e 140kw to me may be what you know as 130kw, or vica versa.
Have you seen Toda B output higher than 120kW on stock bottom end? Regardless of Dyno? I don't think I've ever seen lower than 125kW..?
I've been told a lot of 'do this' and 'don't do that', but have had little reasoning on 'why' except from Adrian with respect to the CTR pistons.. I didn't want to bother him / use his time when unlikely he is getting business out of it -- Thats why I posted here, otherwise I would have called him straight away. I am taking your wisdoms and experience and trying to apply them to my situation where I have restrictions. Thats why I am asking why you made those decisions. I do appreciate all your input.
(and that was the skinny version)
Benson -- I read the Cam Thread and saw post number 403 where you are talking about the BYP 124kw@wheels car needing larger cams (i.e Toda C). Isn't he running stock internals as well? Why would you recommend differently here? Only difference is ITB's really, which are on the cards in any case.
(Again -- The reason I ask is to understand from your experience).
maybe re-phrase your question, in light of the input you have considered?
FYI - i built my B20VTEC for the reasons i told you BEFORE: http://www.clubitr.com.au/forums/sho...0&postcount=15Quote:
Thats why I am asking why you made those decisions
but that was when you were talking about S/C vs N/A
so can we get a clarification of what it is you seek? or is it that you are unsure of what you want, hence why you seem so confused?
so your car is 121kW at the front wheels now?Quote:
Originally Posted by ewendc2r
what is your goal? 140?
you want to see 19kW from head + cams? 15% increase?
I think i was being a shit stirrer. But yeh, that b16a made decent peak power but didnt drive as nice as the 118kw when it had ITB's.Quote:
Originally Posted by ewendc2r
Look man, buy a b20 and build that with the head you bought slap it on. Then you can salvage your ITR motor and sell it for 2.5-3k as a long block. Your not thinking, why hack up a good ITR motor?
Only slightly off topic... but could be useful for the OP.
For the record... the problem with CTR pistons or any high dome piston for that matter, is one of flame propogation. The flame front can be irratic due to the high dome design blocking some of the chamber floor until the piston has moved well past TDC.
ALL this can be overcome with good tuning and a cartridge wheel pointed in the right direction.
Some people won't tell their reasoning behind their dislike for CTR's... most likely because they are regurgitating something they read and don't actually understand what is happening in the chamber when the fire is lit. I think they call tem "urban myths";)
can the design of the combustion chamber assist this also?Quote:
Originally Posted by 82911
i.e. when obtaining a worked on head - like the OP intends, what is there to look for?
welded up quench area?
Benson -- I realise this is what you are saying, just go the whole hog off the bat. I'll price it up but its more the fact that I don't have access to suitable environment for an engine build nor do i have access to the tools. So I was 'hoping' to install this head for starters, then put the same head on a built block down the track in say 12 months, when it is more ... convenient.
TB - Yes - I am estimating increase of at least 10% top end from cams alone. I think the head work may net another 3-5%. I will be removing AC at minimum to reduce parasitic drag. Thinking of getting an electric water pump to remove the losses there as well. I don't think that is unreasonable .. ?
I am clear in what I want, how I go about it as another thing... I want a road registered track car.
Benson - I understand your point. The best way is without doubt going down that path and I would go that way if I didn't have circumstances playing against me and don't want to pay massive labour costs for the build ie do it myself. I am prepared to accept it'll likely cost more in the future as a result (albeit not a great deal, mainly tuning).
I understand everything said .. Its not only bang for buck, its bang for ease of installation / effect of modification at this stage.
Just spoke to a friend with DC2R - He had 139kW from Toda B setup (Built engine, 12.6:1) very very strong mid range. And after all that, he says '**** going NA just supercharge it' lol. So to end all of this the Head is something I should get in any case. I'll buy the head and bolt it to my motor with either stock cams or mild cams (Toda B or less) for the time being. I'll supercharge it down the track in which case a higher flowing head is benefical anyway..
Thanks for your help
82911 -- Now we're talking.. thats the sort of info I want, tech stuff..
I'm the sort of person that needs to know the underlying essential events / actions / reactions to piece together the total picture. I'm not good with being told here, this is the best way.
The ideal is to design the piston dome and chamber roof to match each other for profile.
The welding of quench pads is done to reduce chamber size and add compression, it can also hinder flame propogation if it is not done with consideration of piston dome profile.
When i am designing a chamber shape i will tend to profile shape the piston moreso than the chamber roof (head). This is not because one is better than the other, just that removing the obstructions from the piston dome also reduces the piston mass, so it is win, win.
As for chamber modification, I would bias the design of the chamber to assist flow past the valve seat and across the chamber floor more than look for ways to bump the compression up with mods to the chamber.
Cheers Greg..
If your going to boost it, then save your money. just about any reasonable flowing head, and I include with that any stock B series head, is going to flow plenty of air once you put an atmosphere or so of boost behind it.Quote:
I'll supercharge it down the track in which case a higher flowing head is benefical anyway..
Porting a head is all about flow path and airspeed, both are superflous once you add boost.
Cheers Greg..