Toyspeed.org.nz Message Board

by **ae92levin** » Thu Jan 26, 2006 12:28 am

Ive got a 4agte.

Long story short engine went bang. The 4age was a redtop bigport tvis engine (10:1 or something close) running 8psi, standard compression ratio. It was tuned for 8psi. I have a 4agze which is going in shortly (8:1) and I know I need it to be re-tuned because of the compression difference.

So if im thinking correctly.. since its tuned for 10:1 running 8psi, if I didn't get it re-tuned there will be way to much fuel on the 8:1 4agze running 8psi correct?

Is it possible for me to boost a few more pounds, say 10-12psi so it won't be to rich? I was wondering if anyone would be able to help me out with this, even if there is no possiblity of simply upping the boost i am still rather curious to know.

Cheers

EDIT: And im not using the 4agze computer when I swap the engine.

by **EVLGTZ** » Thu Jan 26, 2006 7:19 am

what computer are you running then?

WOuld be worth getting it tuned right if ya wanna get the most out of the cars performance

by **ae92levin** » Thu Jan 26, 2006 6:39 pm

Its only a SAFC, I have no problem with getting it tuned. I was just curious to see if someone had some sort of way to figure it out how much fuel is being used on 8psi on 10:1 and find the same amount of fuel being used on 8:1 on watever psi it may be.. if you get what i mean

anyone?

by **vvega** » Thu Jan 26, 2006 6:46 pm

interesting
i would have thought the tune would have be in the timing than the fueling

v

by **Lloyd** » Thu Jan 26, 2006 6:47 pm

Likewise. FOr a given amount of air you want a given amount of fuel (more or less). Compression doesn't change that

by **SUBARUCONVERT** » Thu Jan 26, 2006 7:47 pm

yeah be more in timing than fuel, but also the volumetric effic will be differnt for the gze, so will have some effect on mixtures in a MAP sensored car, if urs is?

by **ae92levin** » Fri Jan 27, 2006 2:53 am

Yes it is map sensored.

Can someone please if they can try to explain to me how the SAFC actuly works?

Im basicly questioning if the ze will be alright to boost at 8psi on the safc that was tuned for the ge. Does the safc have any sort of warning if you are detonating?

cheers for the help so far keep it coming

by **Low_Aa63** » Fri Jan 27, 2006 2:57 am

slap a trd head gasket on ur gze then you wont have to worried bout your low compresion then!

High compresion boost is where the power is!!

by **rage** » Fri Jan 27, 2006 3:30 am

HRT wrote:Likewise. FOr a given amount of air you want a given amount of fuel (more or less). Compression doesn't change that

are you saying that if you had a computer tuned for an engine of say 8.5:1 compression, and then you changed the rods and pistons to give a 10:1 compression, that the computer would still deliver the correct ammount of fuel? as in the engine will be running normally and not rich or lean ?

by **IH8TEC** » Fri Jan 27, 2006 4:20 pm

rage wrote:
HRT wrote:Likewise. FOr a given amount of air you want a given amount of fuel (more or less). Compression doesn't change that

are you saying that if you had a computer tuned for an engine of say 8.5:1 compression, and then you changed the rods and pistons to give a 10:1 compression, that the computer would still deliver the correct ammount of fuel? as in the engine will be running normally and not rich or lean ?

he's talking the other way around though,

Low_Aa63, the trd metal headgasket will not make that much difference to it at all, i went from a 1.2 std gze one to a .8mm trd metal headgasket, yes my block and head were skimmed, bu my compression still sits right around 8.0-1 as standard, probably even a bit lower

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Low & High Compression 4agte (Fueling + Boost)

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