Toyspeed.org.nz Message Board

by **Malcolm** » Wed Apr 29, 2009 10:28 pm

Yes, but it's not infeasible, which was my point

by **soopachargen** » Wed Apr 29, 2009 11:02 pm

how does the car handle? power is all good to brag about but can you effectively use the power you have? its no good having a whole lot of power if you cant get it to the ground.

by **Celica RA45** » Wed Apr 29, 2009 11:21 pm

im using 13.5 to 1 on pump fuel which is either 98 mobil or BP and i also can use united 100 the 2 differences are 1 timming and how much fuel goes in
on united i can use 27 degress full advance timming
on 98 its only 24 but this uses a fully reprogramable ecu

OMG so shiny! · by **Dell'Orto** » Thu Apr 30, 2009 12:29 am

Malcolm wrote:
Dell'Orto wrote:Yeah 13:1 wouldn't really be feasible on pump gas, maybe if you backed the timing right off but what would be the point?

Our car runs 12.5:1 with up to 14psi of boost, no intercooler, on pump gas. It's all in the tune (well, a lot of it is).

I'm sure a bike head has a far better designed combustion chamber than a car one.

by **Adamal** » Thu Apr 30, 2009 12:29 am

Malcolm: Your car is also very light isn't it? So it wouldn't have heaps of load put on the engine.

Website · by **Bling** » Thu Apr 30, 2009 12:41 am

Yeah lets see you tow a boat with that compression :lol:

by **Malcolm** » Thu Apr 30, 2009 1:13 am

Adamal wrote:Malcolm: Your car is also very light isn't it? So it wouldn't have heaps of load put on the engine.

No, but holding the engine at constant RPM at full throttle on the engine dyno puts about as much as is possible to put on an engine.

Certainly the engine design plays a big part, I'd imagine things like rod ratio and geometry of the combustion chamber have a big effect, but I think that you'd probably find the 2zz would be alright with that kind of compression on 98, it would just take some careful tuning to stop it getting destroyed

by **Adamal** » Thu Apr 30, 2009 1:47 am

Ahh ok. Well, if theres anyones word that I'd take on TS, it'd definatly be Malcolm's.

by **JRS** » Thu Apr 30, 2009 8:24 am

high compression pistons like that are designed for large overlap camshafts. if the intake valve doesn't close until the piston is half way back up the the bore again then you don't get the amount the full amount of compression indicated by the CR.

the later the intake valves close the more "compression" you "lose". so to regain the compression lost by the big cam you increase the compression ratio.

sticking 13:1 pistons in an otherwise stock motor would probably be a disaster.

by **~SlideWays~** » Thu Apr 30, 2009 9:39 am

sergei wrote:
Malcolm wrote:
Dell'Orto wrote:Yeah 13:1 wouldn't really be feasible on pump gas, maybe if you backed the timing right off but what would be the point?

Our car runs 12.5:1 with up to 14psi of boost, no intercooler, on pump gas. It's all in the tune (well, a lot of it is).

Very normal for diesel engine, amazing for petrol...

17.6:1 + turbo baby! Pitty mine only makes 120hp :lol:

by **Malcolm** » Thu Apr 30, 2009 9:49 am

Adamal wrote:Ahh ok. Well, if theres anyones word that I'd take on TS, it'd definatly be Malcolm's.

Don't take anyone's word Adam

I don't make shit up, but I'm still wrong plenty :oops:

by **TRD Man** » Thu Apr 30, 2009 10:15 am

BZG|Bling wrote: So it would be better to ask if its worth just changing pistons for a performance gain etc. Just my 2c

doublezero's question was perfectly legitimate and required no elaboration.
Specific questions ought get specific answers rather than presumption that they need a lesson in engine dynamics.

We ran our rally 2E motor at 14 to 1 entirely on pump fuel which in those days was 96.
We ran our 3SGE at 12 to 1 mostly on Avgas but occasionally on pump fuel.
Neither engine had issue and both had mountains of torque.

I wouldn't advise you either way on the TRD 2ZZ pistons. You should seek advice from someone with experience of that particular engine or get your Toyota agent to ask TRD directly.
I suspect the likely answer answer will be not to use them with our pump fuel.

by **doublezero** » Thu Apr 30, 2009 11:17 am

TRD Man wrote:
BZG|Bling wrote: So it would be better to ask if its worth just changing pistons for a performance gain etc. Just my 2c

doublezero's question was perfectly legitimate and required no elaboration.
Specific questions ought get specific answers rather than presumption that they need a lesson in engine dynamics.

We ran our rally 2E motor at 14 to 1 entirely on pump fuel which in those days was 96.
We ran our 3SGE at 12 to 1 mostly on Avgas but occasionally on pump fuel.
Neither engine had issue and both had mountains of torque.

I wouldn't advise you either way on the TRD 2ZZ pistons. You should seek advice from someone with experience of that particular engine or get your Toyota agent to ask TRD directly.
I suspect the likely answer answer will be not to use them with our pump fuel.

Thank you TRD man. I will do that. Most helpful comment so far.

by **Adamal** » Thu Apr 30, 2009 12:21 pm

Malcolm wrote:
Adamal wrote:Ahh ok. Well, if theres anyones word that I'd take on TS, it'd definatly be Malcolm's.

Don't take anyone's word Adam I don't make sh*t up, but I'm still wrong plenty

Hehe I'd still say you're pretty knowledgable.

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