2jzge modifications worth it ?

[Enchanter]

I have searched to no avail and I hope these questions aren't deemed too stupid....

From the start I have always had the aim of building up a NA 2jz for the ma61, preferably a vvti for the better mid range power.
ITB, tuned length extractors, cams and stand alone ecu were (are?) on the cards.
My aim is to produce about 230kw (at the flywheel), with out touching the bottom end, for both street use as well as hillclimbs and circit days. Fuel economy doesn't worry me at all as its not my daily driver.

However I keep learning more about these engines and how much fine tuning etc Toyota have put in to them, ACIS for example. Im worried that if I start to remove their intake systems etc and replace them with what looks like a better system, I may actually go backwards in power.

Im also not going to be forking out for a Motec, I was hoping to run it with a megasquirt (I like the hands on approach), but will it be able to deal with the vvti, indeed can I even change the cams of a vvti at all and if so will it make much difference ?

Cheers

[CrUZida]

Only you can answer the 'is it worth it' question, as you will be forking out the dollars.

230kw is 306hp, or 102hp/L, which is very achievable, but in doing so on a stock bottom end you may lose a fair gob of low down power.

You are going to have to decide whether this would be an acceptable loss.


Is there any reason to stay with the 2JZ? Class restrictions?
Its just the a 1UZ will do 230kw with just a manual trans, extractors and a programable ecu, have more bottom end, and be 30-40kg lighter.
Also have mucho more potential if you decide.

But if you have class restrictions, that changes everything, and the 2JZ would be the best choice.

[ViPeR_NiPPleX]

[QUOTE=CrUZida]
230kw is 306hp, or 102hp/L, which is very achievable, but in doing so on a stock bottom end you may lose a fair gob of low down power.
[QUOTE]

Why with the stock bottom end would you lose low down power? and what can be done with the bottom end to change that?? i'm guessing this is camshaft/compression ratio related

[JustCallMeOrlando]

You'd lose bottom end power because of the fact that you're not going to be able to increase power without using cams, which is going to shift the power band higher, at the expense of bottom end. I think what CrUZida means by this being worsened if you don't touch the bottom end is that you don't have the option of raising compression to slightly offset this. Either way, you're going to lose some bottom end, the 2JZGE is fairly efficient as is, making 100Nm/L of torque.

[ed]

here some shit i wrote in a basic 7m discussion, but a lot of it is still relevant for any I6 looking for 110hp/L

note tho that vvti can ONLY be run by an m800 or autronic sm4. interference piston/valve assemble make life tougher with cam choice, but it is doable

adapted from here...

http://forums.toymods.org.au/index.p...t=0#msg_151143


Re: 7MGE bore spacing and overbore limit Thu, 14 August 2003 23:09 Go to previous messageGo to next message
oldcorollas wrote on Thu, 14 August 2003 20:11

anyway, steve, here's a *basic* list of what you can easily do to a 7m to shake it up a bit. keep in mind, there are many, many conversations to be had with regards to each of these points, and each of them can be taken to 'silly' extremes - but then youre running into serious motec only territory...

intake:
-cai
-intake pipe
-throttle body/ies
-single vs twin inlet plenum with ACIS
-custom chop manifold with ITB's
-manifold porting and plenum porting
-port matching

head:
-intake porting, from mild to wild
-bowl can have massive improvemnets
-valve seats and seat cutting
-OS valves
-chamber shaping
-decking for CR increase (plenty of meat)
-valve unshrouding
-polishing
-ex valve porting - big gains again
-ex seat cutting
-headers 6-2-1 or 6-3-1 (dunno there?)
-hi flow 2.5" zorst

CAMS
-up to 9mm lift before head recess machining and Shim under modification required
-duration up the ying yang
-valve springs (?)

PISTONS
-truly mssive piston valve clearance (*not with VVTi)
-allows plenty of scope with cam choice, compression machining etc
-pistom crown shaping and polishing
-rings - your call Smile

RODS
-grind and beam polish and peen
-ARP bolts essential

BLOCK:
-GTE block w/ oil squirters (reduce temps a LOT)
-again, given piston tolerances, you can decrease the block deck height significantly (i chopped mine 40thou!!)
-oil return chamfering etc
-external oil cooler fitting stock on some 7mge's
-2 cranks available - single counterweight and double (later models) single is lighter, but less balanced
-i dunno if thyre all like this, but my crank is forged (out of a GTE)
-crank machining, lightening etc

OTHER:
-squish clearance is in your hands - can go to 35thou with stock 7m rods.
-piston squish surface area is ~30%
-head squish area is around ~20-25%

ive happliy squeezed 10.7:1 with basic non-dodgy machining (up from 9.2), and could easily get 11:1... and get this - such machining STILL maintains a non-interference piston/valve fit!!

if you wanted total interference fit, you could go easily to 11.5-12:1 AND run big lift big duration cams, and STILL not have clearance issues (this is with plain old cast ACL jobbies - so not sure how crazy you'd want to go on them anyway!) if you wanted to go custom pistons, the world is yours...

its all shades of grey really - how far down the scale youre prepared to go, what youre prepared to spend and risk, and what you reckon the ECU will run before a motec is required Very Happy

cheers
ed

[ed]

more reading:

http://pforums.company-hosting.com/f...#post839236528

http://www.eng-tips.com/viewthread.cfm?qid=85349



cheers
ed

PS - i have an itb 2jz manifold for sale

[gianttomato]

Im also notIm also not going to be forking out for a Motec....

so you'll be buying an Autronic SM4?

[Enchanter]

so you'll be buying an Autronic SM4?

I think the VVTi idea is out the window, it just gets too expensive compared the the non VVTi 2jz, aswell as the fact is doesn't run a distributor (as I recently learned) so the megasquirt wont like it unless I modifyed it to take one.

I know very well the hows and whys of modifying an "old school" engine but the amount of extra gadgetry attached to the new stuff is just mind boggling and it must all be there for a good reason.

I realise a fair amount is for economy and emissions but some of it is for responsiveness and power too.

In the end if I can make a touch over 100hp/L and have it useable as both a street car and track car I will be happy.

GT, what kind of performance were you able to get from your non VVTi 2jz ?

Thanks to all that contributed +rep for you (if I havent already)

[Enchanter]

Is there any reason to stay with the 2JZ? Class restrictions?

sorry yeah to answer your question yes, under 3000cc class. There are higher classes ofcourse but some of the competition have massive budjets that Im not planning to match.

Im currently running a heavily modified Mitsu Scorpion 2.6 4cyl, the ma61 will be replacing it eventually.

[gianttomato]

All I did was bolt on a set of ITBs, some extractors and a Motec to run it and I'm making 148 rwkW. I have a pretty silly head with serious cams and a lot of other work, some 12:1 pistons and forged rods - hoping to get close to 200 rwkW.

Then I'll do up the spare VVTi.

[Enchanter]

All I did was bolt on a set of ITBs, some extractors and a Motec to run it and I'm making 148 rwkW. I have a pretty silly head with serious cams and a lot of other work, some 12:1 pistons and forged rods - hoping to get close to 200 rwkW.

Then I'll do up the spare VVTi.

Ahh I like the sound of that as 148 rwKW isn't far short of my goal and 200 rwKW blows it out of the water !!

You have put a smile on my face

[ViPeR_NiPPleX]

All I did was bolt on a set of ITBs, some extractors and a Motec to run it and I'm making 148 rwkW. I have a pretty silly head with serious cams and a lot of other work, some 12:1 pistons and forged rods - hoping to get close to 200 rwkW.

Then I'll do up the spare VVTi.

holy crap im making a pitstop at your place next time im in the area!!11

[Alchemist]

Here's my humble dyno graph....

Mods.

HKS Pod
HKS Kansai Extractors
2.25" Cat Back Exhaust

Waynes JZA61(Glen's old 2JZ MA61), already puts out 132RWKW with an exhaust and lightened flywheel, with the extractors Wayne is putting on it I reckon 140 isn't out of the question. Good gains on standard power which is about 110-120RWKW depending on condition of engine.

[gianttomato]

OK. Now that I have convinced you guys that they're worth playing with, I'm going to be the devil's advocate and give you another choice (or two).

Have you considered the 3VZ or 1MZ? Both sub 3000 cc, but very short and extremely light (lighter than a 2JZ). The 60 degree V will ensure you have no clearance issue with the steering. The 3VZ makes about 200 hp (flywheel) std, 1MZ 210hp whilst the 2JZ makes 220-225.

Minuses are 2 heads, 4 cams, F style head with scissor gears and the need to do a RWD conversion (which I am doing with a 3VZ).

[Nim]

If you where willing to fiddle with bottom end, you could see if you could find a short stroker kit for the 1UZ-FE bringing it down to ~3000ccs. Although I don't think many (if any) people have done this. You'd sorta be leading the way which is never good for the general enthusiest with a limited budget, as you are the one who makes all the mistakes that others learn from. Just another option.