Mark And Duncans R32 Build

[Sydneykid]

me too! 100%.

from what I understand though removing the squish zone isn't just about reducing the compression, that's more a by product, and as you pointed out can be returned by skimming the head. I think it's also about the shape of the chamber. obviously with those 2 pads removed you get larger volume but also the shap is different. I think the idea is having a smoother bowl shape gives less hot spots. in a normal head you get hot spots where there are any little angles or casting imperfections and the can cause pre-igntion or uneven combustion. by removing the squish pads you raise this threshold. the aim of course is you can run more timing and more boost which i'm told outweighs any other loss you might have (on a race engine). what convinces me further is that of the fastest GTRs I know in oz and OS, the ones kind enough to share with me what they do headwise they tell me they remove them. I should point out again for a street car the trade of probably isn't worth it (unless you have silly power) as you want be running enough boost and power to make the most of it. but doing one side is aparently a good compromise. for a race car most of these guys tell me both sides is the go. my own head? I did one side. I'll dig up some pics for you in a bit.

To remove or not to remove, that is the question? Sorry Bill.........

In a race engine I never do, because I lose too much compression that I can't get back with head/block machining because of the piston to valve clearance. I am not fan of cutting flies in pistons as that just gives even more hot spots and a thinner piston crown under the flies. You have to keep in mind the reason for squish zones, which is to concentrate and accelerate the mixture towards the spark plug, thus avoiding the potential for incomplete burn at the outer extremities of the combustion chamber. This has the by product of reducing the tendency for uncontrolled burn, more commonly called detonation. Back in the bad old days (of huge lag) decompressing an engine was considered an OK thing to do. But as we got a lot smarter in our tuning, the fuel and intercoolers got better, the need for low compression ratios disappeared. Although some dinosaurs still cling to it.

In a race quality engine, whether it is used on the street or not, I can’t see any reason to do away with the squish zones any more. Unless you use crappy fuel with a lousy tune and don’t care about lag ie; the car is used for drag racing with an auto. I still see some huge boost engines doing away with the squish zones, but that has more to do with poor efficiency in the engine which is what makes the huge boost necessary. If people spent more time on improving the efficiency and increasing the airflow instead of simply turning up the boost, then they would find it unnecessary to decompress by removing the squish zones.

Cheers

Gary

[Angus Smart]

Carbon shaft arrived today....................

but i wasn't home so tomorrow it is!!

[Risking]

Doesnt that suck andrew!!

[Duncan]

...If people spent more time on improving the efficiency and increasing the airflow instead of simply turning up the boost, then they would find it unnecessary to decompress by removing the squish zones......

well cmon then...we need ideas that fit within the budget of this project (ie $0!).

BTW the sway bar links sit a little different to standard, should I run longer bolts with lock nuts to get them closer to vertical? I think they might bind up a bit on their current angles.

[Angus Smart]

Doesnt that suck andrew!!

if there was a working car to put it on maybes

but for now i can only Fap over it.

[Neil]

Doesnt that suck andrew!!

I heard on the grape vine your doing the O/P day/nighter,,,True,???. If so can you bring my spare windscreen honey.

We could actually share my garage and cut the costs. No 15 is mine and if no-one take the other half we end up with tons of room.

Neil.

[Duncan]

speaking of bits being dropped off, 3rd time lucky - the remote filler and roll over cut out for the fuel cell arrived today so thats another job to knock off in our spare time.

BTW we were discussing on the weekeknd......does a sway bar or "anti roll bar" actually stop or reduce the number of times a car will roll? If so that purty yellow solid one that Gary made up for us will be a must.

I bet Mark wished he had a bigger anti-roll bar on this car....

[t01-100]

nice shot of bana's wreck in the back ground... all the big move star cars sit in apple sheds near devonport i hear!

[Duncan]

lol but I'm not going to share the pics where we are pointing and laughing at it

[JAS-25T]

lol but I'm not going to share the pics where we are pointing and laughing at it

Comedy gold!

Im still waiting for TT2007 pics!

[Angus Smart]

Helllll yeahhhhhhhhhh!!

7 months in the making! and they are here!!

8.6kg in total!

Edited October 14, 2008 by Angus Smart

[N1GTR]

Worth the wait?

[Angus Smart]

I dont really know?? haha what a headache it all was tho. i need a 32gtr with a getrag in to test.. or mine will be ready in a month or so..

[haw001]

To remove or not to remove, that is the question? Sorry Bill.........

In a race engine I never do, because I lose too much compression that I can't get back with head/block machining because of the piston to valve clearance. I am not fan of cutting flies in pistons as that just gives even more hot spots and a thinner piston crown under the flies. You have to keep in mind the reason for squish zones, which is to concentrate and accelerate the mixture towards the spark plug, thus avoiding the potential for incomplete burn at the outer extremities of the combustion chamber. This has the by product of reducing the tendency for uncontrolled burn, more commonly called detonation. Back in the bad old days (of huge lag) decompressing an engine was considered an OK thing to do. But as we got a lot smarter in our tuning, the fuel and intercoolers got better, the need for low compression ratios disappeared. Although some dinosaurs still cling to it.

In a race quality engine, whether it is used on the street or not, I can't see any reason to do away with the squish zones any more. Unless you use crappy fuel with a lousy tune and don't care about lag ie; the car is used for drag racing with an auto. I still see some huge boost engines doing away with the squish zones, but that has more to do with poor efficiency in the engine which is what makes the huge boost necessary. If people spent more time on improving the efficiency and increasing the airflow instead of simply turning up the boost, then they would find it unnecessary to decompress by removing the squish zones.

Cheers

Gary

Thanks for the explanation Gary. I know of one engine builder who agrees with you and he was responsible for the head porting on ours, and personally, I did not want to once again remove the head before even firing it up and disassemble the head before even trying it.

Mark

[haw001]

I dont really know?? haha what a headache it all was tho. i need a 32gtr with a getrag in to test.. or mine will be ready in a month or so..

Looks cool though! Got a sort of croc theme going. What sort of weight savings over chromoly welded tube?

[Angus Smart]

Looks cool though! Got a sort of croc theme going. What sort of weight savings over chromoly welded tube?

this is just under 9kg's (can handle 2000ft/lb) tho the other available model is around 6kg's (1000ft/lb)

i am wondering why i went with the larger one in the first place.... oh well i aint waiting another 7 months for one.

[jazzy_j]

That tail shaft looks awesome Andrew! Pity you'll have to get under the car took at it.

[Risking]

I heard on the grape vine your doing the O/P day/nighter,,,True,???. If so can you bring my spare windscreen honey.

We could actually share my garage and cut the costs. No 15 is mine and if no-one take the other half we end up with tons of room.

Neil.

I was going to but all the spots were full by the time I got my entry done. (was waiting to get the car sorted before sending it)

Greg got his in as did Steve Berry so ill probably be there anyhow.

[BezerkR32]

bar thickness divided by the number of adjustment holes equals the maximum amount of roll-overs posible with the bar fitted.

speaking of bits being dropped off, 3rd time lucky - the remote filler and roll over cut out for the fuel cell arrived today so thats another job to knock off in our spare time.

BTW we were discussing on the weekeknd......does a sway bar or "anti roll bar" actually stop or reduce the number of times a car will roll? If so that purty yellow solid one that Gary made up for us will be a must.

I bet Mark wished he had a bigger anti-roll bar on this car....

[haw001]

I must have had a lot of adjustment holes! I knew I should have left it standard.