Sooo Who Has a G63B and wants to get pissed and jealous about what i just got........

[thehive]

LOL sorry, i just had to use that opener to get your attention. but i snagged this little beauty off one of our KIWI brothers in the other side of the world!

BEHOLD!




still ironing out the shipping details but i've got it locked down!! the plan is to ditch the stock carbs and run dual weber downdrafts on this G63B/G64B hybrid motor i'm building!!

I'M PUMPED!!!!

[geezer101]

I had the joy of working on the set of twin Mikuni's and manifold I sold to one of the local guys from sigma-galant today (was set up for a 4G52 astron) Good luck, it's tricky to get them working properly. You may find they need a cam to make the most of them, along with some other engine mods.

[thehive]

well i'm doing a high compression 2.4L around 11.5:1 with a big cam regrind and a header and msd box. i've talked to quite a few of the people on the forums over there and they all agree that the stock carbs are garbage and to defiantly ditch them for something with better turning.... like dual weber downdrafts....

[geezer101]

Nice. Looks like you're on top of the linkages. How are you rigging up the fuel lines on this set up?

[thehive]

Lol have not gotten that far yet. Baby steps baby steps. That last picture is of someone else's build that I was talking to, but the point was that weber downdrafts will fit. Now I would not recommend this set up on a normal G63B as it will prob be too much fuel. But for my set up I plan on using dual weber 38mm outlaws lol

[geezer101]

Using 2 of those bad boys will require some serious jetting down or it will be hopeless to drive with. I spent 3 hours attempting to debug the 4G52 twin Mikuni's and got it to a point where it had a hesitation about 2.5 k rpm and idled o.k.(ish), but it appears his base ignition tune is crap so I have offered to dial his dwell and timing in. Took it for a drive and the minute any load was put on the engine it would flat line. The joys of motoring...

[thehive]

Well I'm going to have the distributor recurved to go with the new cam. I think I'll prob be able to run the they way they are right out of the box. Are you sure you know how much fuel this things going to take with that near 12:1 compression ratio once I run a super thin head gasket? I know that would be too much for a single weber 38mm. I would have to jet it up

[thehive]

i'm sorry man i'm really not trying to be a ass, i do understand that with any multi-carb set up there is deff going to have to be a tuning and prob re-jetting phase. and i welcome it!! i just can't wait to hear both those carbs scream!!

[geezer101]

It would be at this point I'd recommend installing an O2 sensor in the headers (it will help with setting A/F mixture and generally let you keep an eye on what your tune is like). Best as I can tell, to get a G63B breathing nicely it requires 180 cfm + through a carby/intake - the alloy Mikuni/Solex carbies are approx 170 cfm in a single configuration so the twins are more than adequate. The twin carb set up that you've sourced for the G63B will be good to go straight from the box (so to speak). I would guess the factory compression ratio for an engine running the twins from factory is approx 10.5:1. Any other mods on the table?

[thehive]

umm i'm not even in the same ball park as a G63B..... the only thing i'm using that is from the 2.0 in the cylinder head. and it's a non-jet head with roller rockers that has been ported.

now to bring you up to speed... i will be using a 2.4 4G64 8 valve bottom end with this 2.0 head on it to raise the compression to damn near 12:1. then i'm taking the 2.4 cam and having it re-ground and putting it in the 2.0 head. it's a high compression 2.4 liter, no where near a stock G63B........which came with 9:1 compression with the twin set up not anywhere near 10.5:1

here is some part swapping compression numbers that i dug up if your interested
7g 4g64 pistons + Stock (sohc) or 4g63 (dohc) 47cc head = 9.5:1 CR

7g 4g64 pistons + Hyundai 4g67/1.8l 43cc head = 10.034:1 CR

4g64 Sonata/Mighty Max 8v pistons + Stock (sohc) or 4g63 (dohc) 47cc head = 11.3:1 CR

4g64 Sonata/Mighty Max 8v pistons + Hyundai 4g67 1.8l 43cc head = 12.077:1 CR

But there was also a 1.6L version found in Mirages and Hyundai Elantras called the 4g61. If my math is correct, the cumbustion chamber of that head is 37.3556645 (37.4)cc

So...

7g 4g64 pistons + Mirage/Hyundai 4g61 1.6l 37.4cc head = 10.885:1 CR

4g64 Sonata/Mighty Max 8v pistons + Mirage/hyundai 4g61 1.6l 37.4cc head = 13.384:1 CR

i'm going for the set up done in bold with a resurfaced block and head and about a .030 cometic head gasket to bump up the compression even more.

i know i may have confused you by using alot of the 2.0 parts but my motor has the heart of a 2.4 liter lol

[guamboyeli]

well holy hell.... thats bitchin

[geezer101]

Weird. The factory CR for my L200's G63B was 9.5:1 (or was meant to be) I ran into grief getting the correct OS pistons for it and had to settle for a set that was slightly dished (it'll be down to 9.3:1 so not much of a drop). My guess on the CR for the twin carbs was based on it being a performance thing. Can't wait to see what it's like after you've got it up and running!

[thehive]

i do feel what you saying about cfm and fuel being a little to high for daily drive ability and a decent idle thou. i want it to be enjoyable as well as fast. if dual 38mm webers was the thought for full race. i wonder if dual 32/36 webers would be better for street driving. i know the 38mm is fully synchronized and opens both plates as one and the 32/36 is progressive and opens the 32 faster and the 36 plate.

it seems to my that the dual 32/36 would prob drive better but would i lose performance there?

[geezer101]

The 38mm Webers are pretty tame when you consider that guys use twin 45 DCOE's on 2 litre engines (I still don't know why anyone would want to use them on a road car...) . The 32/36 Webers aren't that far from spec when compared to the Mikuni's used on 2.6 Astrons (same size throttle butterflies). My opinion? Use the 32/36 Webers. They are automatically bigger than the Mikuni/Solex carbies on your twin carb rack. Bear in mind the twin carb set up isn't for full on top end power - it's for beefing up mid range without killing bottom end and response (I think the 38mm synchonised downdrafts will be overkill and would wreck performance). Once you have a tune that works with the twin carbies, you'll find there's sweet spots in the acceleration/rpm range where the engine will want to pull like a train. Also, have you considered an adjustable cam gear? It might help with getting the cam into a power band that is optimal for the carbies.

[thehive]

ahhh the adjustable cam gear. yeah i have a "few" actually lol one was just a bad ebay buy but, it did let me know that a adjustable cam gear could be used on these motors. just not that style of one because the marks we're pointed up at the valve cover.
i later found a set like this and had to buy both. they have two holes drilled in them, one for the standard 4G63 and one 90 degrees out (what we need for our side timing mark) makes timing the motor much easier!


yeah i think i'm feeling the dual 32/36 idea too. i can just imagine trying to pull away from a stop sign with the 38mm's and all four of those throttle plates trying to open at once and just dumping fuel.

Reminds me of a friends Honda S2000 one time that had 48mm ITB's, it was a blast to drive and made a amazing intake noise when you were on it, but you always HAD to be on it. it was like a on off switch almost, full bore or barely moving, the throttle was so sensitive. i just don't want my set up to end up like that

[thehive]

I just ran some numbers to compair what the two set ups would be like that what I found wasn't all that bad.

Weber 32/36 x2 equals $580 shipped. And one 32/36 is rated at 325 cfm, x2 that equals 650 cfm
Weber 38/38 x2 equals $680 shipped. And one 38/38 is rated at 380 cfm, x2 that equals 760 cfm

so for price and performance and tuning I may just be going with the two 32/36's

[pennyman1]

not to rain on your dream, but you do realize that a 360 mopar motor with a mild cam runs great with only 390 CFM, so 650 to 760 cfm is way overcarbed. I have seen somewhere (probably ebay) where a guy grafted a 4bbl base and a holley 390 4 bbl carb onto a 2.6 manifold. Car Craft has a carb selector calculator that you put in your parameters and it will tell you what size carb is optimal. The looks of that setup is killer, but it will be killing your performance as well. Now if you could find dual 28 mm syncro carbs, that would be much closer to what you need. I have a set of 40 dcoe webers and the sidedraft manifold for them, but my friend that races hondas with them said to forget running them on the street - they will be a nightmare to keep in tune.

[thehive]

Well I have plenty of other supporting mods and and such (BIG cam, headers, roller rockers, light weight rods, cometic head gasket and arp everything, no balance shafts, and 11.5-12:1 compressionIt just comes down to jetting and tuning of the set-up. I know it won't be a easy road, but I also know no one else in America will have a set up like mine. If I can take the time to clay bar the engine I can take the time to re-jet and tune a carb

[thehive]

Also I've already talking with one owner running dual weber 32/36's in his Sapporo on a tuned up G63B and they seem to be running great for him

[geezer101]

Are you sure those cfm's for a 32/36 weber are correct? I would think they'd be about 200 cfm. This is why they work so well compared to the Mikuni (which is about 180 cfm). 400 cfm 'ish' into a 2 litre is more than enough to get it moving if the set up is tuned right.

[thehive]

well shoot, i don't know now. after about 2 hours of re search ive seen CFM numbers from 220-325. i don't know if there is different versions of the 32/36 out there that maybe flow more? this is from the Pegasus page where they are selling the carb for race projects, they rate it at 240 cfm

CFM https://www.pegasusautoracing.com/pr...p?Product=1580

this is from a toyota site:
Carb Flow
Stock 20R Aisan 190 cfm
Stock 22R Aisan 326 cfm
Weber 32/36 325 cfm
Weber Dual 38 390 cfm (Downdraft)
Weber Dual 40 405 cfm (Downdraft)
Dual Mikuni 40 PHH 724 cfm (181 cfm per tube)
Dual Mikuni 44 PHH 844 cfm (211 cfm per tube)

annnd this is from a datsun site:

for a DHLA side draft vs. a DRLA down draft.
48 DRLA = 388.5 CFM
45 DRLA = 329.3 CFM
44 IDF = 292.3 CFM
40 DRLA = 266.4 CFM
40 IDF = 212.8 CFM
36 DRLA = 205.8 CFM
The carbs were tested on a Superflow 110 flow bench @ 10" of water

so right now i really have no clue. might warrent a call to weber and ask myself

[Rahtid]

what cam do you plan on running,

[thehive]

a regrind of the factory 2.4 cam by Schneider. it's good for 291/291 in/ex duration right from the factory. not sure about lift yet but i'm sure they can beef it up!!

[Rahtid]

I was also thinking of using a schneider cam,I have a spare cylinder head getting ported and polish,with stainless steel valves with bronze valve guides

[thehive]

UPDATE!! the manifold made it here to the states, and i couldn't be happier!!! here are some update pictures and comparison pictures if anyone is interested

on the stock motor still in the truck:


some comparison photos of it with and without the carbs:



and now a peak and my set-up so far with the non-MCA roller Galant head and such: