questions from an idiot

questions from an idiot

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dragstar

Original Poster:

3,924 posts

218 months

Friday 3rd October 2003
quotequote all

please help..i need to know the answers to these questions:


1)DTH throttle bodies...um what do these do different to normal throttle bodies?
i know they are "down to head" TB's but where about do they actually go? looking by the pics, they look like they fit imbetween the manifold and bloc (this cant be right). why does the ECU need to be remapped?

2)why when a head gasket goes water leaks into the sump? i thought the HG was just another seal in the head?

3)i think the difference between a VVC engine and normal 4 cyclinder is the rotational speed/cycle of the cams, but what physical differences are in the bloc? can you easily convert a 4 cyclinder to one of VVC?

4)how do headers increase performance?

please help..really pissing me off.

cheers in advance

>>> Edited by dragstar on Friday 3rd October 22:30

MGBV8

160 posts

224 months

Saturday 4th October 2003
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tvradict

3,829 posts

242 months

Saturday 4th October 2003
quotequote all
dragstar said:

2)why when a head gasket goes water leaks into the sump? i thought the HG was just another seal in the head?


The head gasket provides a seal between the head and the block, but there are water and oil lines running up and down the block into the head, if the gasket 'goes' between a water and an oil line the water will leak into the oil line and eventually find it's way into the sump.

edc

8,349 posts

219 months

Saturday 4th October 2003
quotequote all
dragstar said:

please help..i need to know the answers to these questions:


1)DTH throttle bodies...um what do these do different to normal throttle bodies?
i know they are "down to head" TB's but where about do they actually go? looking by the pics, they look like they fit imbetween the manifold and bloc (this cant be right). why does the ECU need to be remapped?



Direct to Head is my understanding ie no manifold, bolt straight on. You don't have to remap the ECU but if you don't what's the point of the expense of DTH bodies unless you have a very clever self adapting ECU?


dragstar said:

2)why when a head gasket goes water leaks into the sump? i thought the HG was just another seal in the head?



Head gasket ensures a good tight fit between bottom end and top end. There are oil ways and water ways that run between the two. When the gasket is knackered there is the probability that oil and water will mix.

EDIT: oops, already answered.

dragstar said:

3)i think the difference between a VVC engine and normal 4 cyclinder is the rotational speed/cycle of the cams, but what physical differences are in the bloc? can you easily convert a 4 cyclinder to one of VVC?



The block does not need to be different. The diffeence is in the cam profiles, lift, duration etc and the control of the ECU over exhaust and inlet cams. The only thing different in the block may be tighter tolerance on balancing so the bottom end can cope with any increase in the rev range and not shake itself to bits at 7k+ rpm.




>> Edited by edc on Saturday 4th October 12:29

dragstar

Original Poster:

3,924 posts

218 months

Saturday 4th October 2003
quotequote all
cheers.

so what does an inlet manifold look like?

MGBV8

160 posts

224 months

Saturday 4th October 2003
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annodomini2

6,332 posts

219 months

Saturday 4th October 2003
quotequote all
VVC or Variable valve control (rover's version anyway) requires a special head casting to support vvc, it changes the timing of the inlet valves.

edc

8,349 posts

219 months

Saturday 4th October 2003
quotequote all
dragstar said:
cheers.

so what does an inlet manifold look like?


Inlet manifold is simply the bit of metal atop the engine that takes the air from the inlet through your air filter and passes it into the engine. You might see it on some engines with red painted 'DOHC' or something similar.

z_chromozone

1,436 posts

217 months

Tuesday 14th October 2003
quotequote all
dragstar said:
cheers.

so what does an inlet manifold look like?


Mine looks a bit like my exhaust manifold, only less rusty

Sorry,

Z

danger mouse

3,828 posts

229 months

Tuesday 14th October 2003
quotequote all
My inlet manifold says PGM-Fi on the top, and wouldn't go rusty as it's cast from Aluminium....


..but I reckon Mr Dragstar would have known that the second he looked under my bonnet.

I was going to give you the benifit of the doubt, and just ignore these blatantly inane questions, but judging by your profile, I suspect you do know what all the answers to the questions below are. Either that or you have spent a hell of alot of dosh without knowing what you were buying...

...don't think so.

Just seeing how many genuine guys would answer your silly questions were you?

It's not nice troll. Flame me if I'm wrong though, I insist.


Mouse.

Captain Muppet

8,537 posts

233 months

Tuesday 14th October 2003
quotequote all
edc said:

...The block does not need to be different...


Unless the oil feed to the cam profile switching gubbins in the head runs through the block casting Honda stylee.

Captain Muppet

8,537 posts

233 months

Tuesday 14th October 2003
quotequote all
From his profile:
dragstar said:

titanium 111s s1 with these
extra goodies...
lotus suspension, lotus exhaust, throttle body, ptp induction kit, sport 160 wheels, advan neova tyres, momo removeable wheel, chrome indicator sticks and other 111s usuals. also clear side repeaters and clear rear lights.
NEW:
sony minidisc headunit (mdx-m690) and pioneer bass tube.


So much money to spend yet unable to operate a google search. So sad.

dragstar

Original Poster:

3,924 posts

218 months

Wednesday 15th October 2003
quotequote all
Captain Muppet said:
From his profile:

dragstar said:

titanium 111s s1 with these
extra goodies...
lotus suspension, lotus exhaust, throttle body, ptp induction kit, sport 160 wheels, advan neova tyres, momo removeable wheel, chrome indicator sticks and other 111s usuals. also clear side repeaters and clear rear lights.
NEW:
sony minidisc headunit (mdx-m690) and pioneer bass tube.



So much money to spend yet unable to operate a google search. So sad.


hey!! it easier, nah nicer to get a response from engine-"experts" rather than look at sites which are inevitabley trying to sell me something, and so harp on about "x power gains.." which i really dont understand.

and to the guy who says im "trolling" im not (consider yourself flamed). yes i did buy the car, with some help by my parents (im 20) but im not an engine expert...those mods were put on by the previous owner.

dont know about you, but when i buy a car, i dont sit there and masturbate over the stats, and workings of the engine. i see a car. like the drive. like the looks. and if it "works" then i buy.

its only now that i have in interest in how engines work.
i really like the site.. www.howstuffworks.com on how engines work but its not complete enough

danhay

7,176 posts

224 months

Wednesday 15th October 2003
quotequote all
dragstar said:

4)how do headers increase performance?

I presume you're referring to tubular exhaust headers? Good headers should be more free flowing due to less sharp bends, and also have matched length pipes from each cylinder which enables you to use pulse tuning....They also sound better

Captain Muppet

8,537 posts

233 months

Wednesday 15th October 2003
quotequote all
dragstar said:

hey!! it easier, nah nicer to get a response from engine-"experts" rather than look at sites which are inevitabley trying to sell me something, and so harp on about "x power gains.." which i really dont understand.

and to the guy who says im "trolling" im not (consider yourself flamed). yes i did buy the car, with some help by my parents (im 20) but im not an engine expert...those mods were put on by the previous owner.

dont know about you, but when i buy a car, i dont sit there and masturbate over the stats, and workings of the engine. i see a car. like the drive. like the looks. and if it "works" then i buy.

its only now that i have in interest in how engines work.
i really like the site.. <a href="http://www.howstuffworks.com">www.howstuffworks.com</a> on how engines work but its not complete enough



You might have to try it the old fashioned way and get a book out of the library. I recommend the Bosch Handbook (probably spelt wrong - it's on my desk and I'm at home). It'll tell you anything you'll ever need to know about everything inside your car. It's the book I wish I had when I did my degree.

Edited to add paranoia: What makes you think the good people on PH know what they're talking about? And never assume that they aren't trying to sell you something - if your Elise took 185/60R14 tyres I'd be trying to sell you my old slicks by now.

>> Edited by Captain Muppet on Wednesday 15th October 18:18

danger mouse

3,828 posts

229 months

Wednesday 15th October 2003
quotequote all
A cunning, calculated and evil ploy from Mein Capitan to draw me back out of the wood work, but those slicks are skinnier that my current road tires.

Ok Dragstar, sorry.

Some of the questions did look like they were designed to look inane, and yet almost seemed to betray more knowledge than you meant to let on (did you see where I was coming from there Muppet?)... and that would have meant you were taking the pi$$ out of us and I call that Trolling.

OTOH, you seem to have your heart in the right when it comes to your car, so I doff my cap to you Sir, and so do hereby apologise.

I was in a bad mood yesterday, and you caught the sharp edge of it. Instead, may I welcome you to PH, even though I know you are not a total newbie, and I hope you get what ever you need/want from it.


endgroveleD Mouse

BTW: I've given up to$$ing off over engine stat's. I've got a bad memory, and it's hard to revise them when the pages of my CCC mag's are gunked together.

danger mouse

3,828 posts

229 months

Thursday 16th October 2003
quotequote all
By way of further groveling:

From what you have said, I'm guessing what you are really asking is "what the hell is all that gubbins on the list in your profile/under your bonnet, and what can you realistically do to make it all even quicker, hence the VVC question.

Firstly, DTH throttle bodies are exactly that. Instead if having one butterfly valve that controls air flow into the engine, up stream of the intake manifold or header (as the americans call them), the DTH's form a single butterfly for each cylinder down stream of the intake manifold. This has two main advantages.

1) Each throttle body can be tuned specifically to the needs of the cylinder it feeds. Where as with the normal single throttle, the set up has to be a compromise between the needs of all the (four, in the case of the Elise) cylinders.

2)The longer/straighter/unobstructed the inlet tract the more intertia the air flowing through it has which, when properly sorted, can increase the ram charging effect, increasing power (well torque really, but that's a whole other can of worms!) kind of the same way as a turbo might... only with out the turbo, and nowhere near as much.

The reason why the ECU would have to be re-mapped is simply that standard ECU's are only programmed to deal with one throttle body not four.

I think the head gasket one has been covered pretty well. I'd just add that if you only got water in the sump you got off lightly. The K series, as with most engines, has both oil and waterways flowing through from block to Head (I seen 'em once they've blown, so I know). So when it does blow,and on a K it's when rather than if, you might well get oil in the cooling system too. The water in the sump will form from condensed steam in the oil ways and work it's way all round the engine. That's why the easiest check for a knackered HG is to look inside the oil cap, where steam mixes with the oil thrown up by the valve train to make a sludgey mayo'like emulsion. Bad news!

With regard to the differences between a standard and VVC block: I don't know for sure, but I think there are some. It wouldn't surprise me, for instance, if the crank bearings were made a bit beefier to take the extra torque the VVC engine produces. Bear in mind that the K-series was originally designed as a 1.4litre 102bhp max motor. In your Elise the same size block has been heavily modifed to give an extra 100cc's per cylinder, which is alot.

If you are looking to go convert to VVC, it would be far far simpler to get a VVC motor and swap your tasty bits over I reckon.

The last bit about headers I kind of covered earlier. You can acheive the same sort of effects of flow inertia by tuning* the lengths of the exhaust manifold and the bore of the exhaust itself. The flow of exhaust out of the engine can be made to leave a partial vacuum in the cylinder, so when the intake valves open, so even more air is sucked in. This is called scavenging and is what the VVC, VTEC, VVTi etc systems are designed to opptimise. The VVC is a good one thoug as it acts on both the inlet and exhaust. the Traditional VTEC was only ever on the intake cam.

I hope this is more what you were after. If you want know more, find any book on tuning engines by David Vizard, and all will be revealed.

Good Night,
Mouse.

*for those really in the know: I realise this is not the whole story, but I'm tired, and poor old Dragstar will be in need of a shave by now.

dragstar

Original Poster:

3,924 posts

218 months

Thursday 16th October 2003
quotequote all


no problems, and cheers for the info!!

danger mouse

3,828 posts

229 months

Thursday 16th October 2003
quotequote all
Amazing what a guilty conscience'll drive you to.

annodomini2

6,332 posts

219 months

Thursday 16th October 2003
quotequote all
danger mouse said:


With regard to the differences between a standard and VVC block: I don't know for sure, but I think there are some. It wouldn't surprise me, for instance, if the crank bearings were made a bit beefier to take the extra torque the VVC engine produces. .


The blocks and bottom ends are the same.

danger mouse said:

The VVC is a good one thoug as it acts on both the inlet and exhaust. the Traditional VTEC was only ever on the intake cam. .


VVC works the inlet valves only. and has infinite timing adjustment but no lift adjustment.