2.4 build

[95patalon]

I figure I will post here since I am a newb to the 4g64 platform. I am looking into the 2.4 platform with the 4g63 head. I did my research I know whats involved. I only have a few more questions do the 2.4 crankwalk, and I want input from 2.4 user about pro's and cons of running this setup beside you cant rev high. Like pro's and cons about running a large frame turbo example gt42. ( not leaving bottom end stock )

 

[okm12346]

Well since failing oil squirters being the main reason for crankwalk, and more specifically the absence of them on the 4g64 block makes it less prone to crankwalk. I havent heard yet for crankwalked 64 yet, but you never know.

Well pretty much all non mivec mitsubishi engines make the most power at 5 -6k and its the same for 4g64. you can rev it high, but its just pointless since it wont make power. you can always put a larger turbo side housing to spool later if you want to make power at higher rpms. 4g64 makes the same power as 4g63,but at lower rpms.

As for building it, i cant tell you what to buy, but i can advice you on some things. if you want forged crank you can get one off 3g Eclipse 4g64 or 8g Galant 4g64. this will cost you way less than eagle. Another budget buy is evo 8-9 pods instead of 2g or aftermarket. these days they go for $40 on EvoM.net. You just have to pick up some pistons.

 

[95patalon]

Now should i expect only a 500rpm or 1000rpm faster spool difference with 2.4 compared to a 2.0. ( turbo gt42 with a .96 ar)

 

[okm12346]

probably around 500, but such a big housing would be spooled around 4500 rpms and if you rev it to 6-6.5k, it would give you a powerband of 2000-2500 rpms which is not worth it. you want it to spool around 3 - 3.5k for broader powerband

 

[DashLaflash]

Any engine can crankwalk. I don't know any actual statistics, but some people build the g4cs 2.4l because its a 6 bolt and less prone to crankwalk than the 7 bolt 4g63 and 4g64 supposedly are. The 2.4 is not as rev happy as the 2.0 but if its built right you can rev it pretty high. I've heard of people revving their 2.3l to 7500 or 8000. It increases spool time by 500rpm but it decreases your maximum rev limit. That's why some people would rather have the extra 500rpm spool time on a big laggy turbo but be able to rev it to 9000+rpm. It all depends what your looking for. The extra 500rpm would be nice on a street car but with more of a track car especially with a gt42 the 2.0 might be better.

 

[95patalon]

Now I heard some people taking the 2.4 to 8k. okm12346 said the motor doesnt make more power over 6.5. But the turbo should still be making more power at that level is this true.

 

[tenn-gsx]

It will continue to make power to whatever rpm the turbo and valve train will allow. You may just end up slinging a rod sooner because of the extra mass on the internals. A longer stroke 2.4 engine will take more abuse with revs above 6500-7k than the shorter 2.0. If you build the engine properly though you can still get the same hp and usually more tq than the 2.0 just sooner. You just have to spend more time and care building the bottom to handle rpms above 6500 or so. There are TONS of guys who rev a 2.3 to 7500. It all depends on how much money you want to spend building it.

 

[95patalon]

I would at least mustard atleast 7500rpm so i dont fall out of boost between shifts. I dont want to be high reving i am not a honda guy

 

[LocknessMonster]

Is this a street car or a drag car? Im in the process of picking up a 4g64 block and im going to destoke it to 2.1L. If your going with a big frame turbo I would say the destroker 2.1 or even the 2.2 might work out well for you. Heres magnus motorsports engine list for you to check out.

http://www.magnusmotorsports.com/tech/DetailedEngineList.pdf

Also someone from this forum posted up about the main cap dowel pins that have been released. This is a great mod for the money. Although not proven, they might help you out with your crankwalk concern. Good luck with the build

EXTREME PSI : Your #1 Source for In Stock Performance Parts - Main Bearing Cap Alignment Dowel (MBCAD) Kit : Mitsubishi Eclipse 90-99

 

[TURBD]

I like the fact that you make power lower in the RPM's as our tranny hates high RPM shifts. I would suggest a smaller turbo on the 2.4 to get on boost sooner. What are your HP expectations?

 

[95patalon]

This is going to be a street car but not a dd. I had my heart set on doing a 2.4 build with a gt42 ... I know it been done someone has to be reving at least 7.5rpm without problems.

 

[DashLaflash]

It will continue to make power to whatever rpm the turbo and valve train will allow. You may just end up slinging a rod sooner because of the extra mass on the internals. A longer stroke 2.4 engine will take more abuse with revs above 6500-7k than the shorter 2.0. If you build the engine properly though you can still get the same hp and usually more tq than the 2.0 just sooner. You just have to spend more time and care building the bottom to handle rpms above 6500 or so. There are TONS of guys who rev a 2.3 to 7500. It all depends on how much money you want to spend building it.

Not necessarily. A lot of people rev their 2.3l to 7500 with just some eagle rods and a set of stroker pistons. This is the same price as a set of forged internals for a 2.0. If you were going to be using a gt42r you would want a seriously built engine anyways which = big $. If I built a 2.3 I would definatley rev it to 7500 or 8000.

 

[tenn-gsx]

7500 should be fine. Just make sure you use quality parts and either use a good shop or DO YOUR RESEARCH on the clearances. A 2.3 uses the same crank just different rods and pistons so they are a little lighter.

 

[okm12346]

The reason you won't make power up high with a 4g64 isn't entirely because of the longer stroke.

stroke is a factor in the rod angle, but its actually the rod angles that cause it to be volumetrically inefficient at high rpms.

the steep rod angles on the 4g64 grant a high piston velocity.
so high that when the engine revs beyond a certain threshold of HP increase, it will actually yield diminishing returns.
The pistons move so quickly, that smaller and smaller volumes of air have the time to enter the combustion chamber.


lets say you are drawing 5 grams per cylinder per rev @ 4000RPMS.
on a 4g64 even with good cams the pistons move so quickly at 8,000 rpms that you are only moving 2 grams per rev(these numbers are completely erroneous, and are only mentioned to deliver the basic concept)
however on a 4g63, because of the lower lod angles and lower piston velocity, it may continue to move more air until a much higher rpm value, yet due to lower displacement move much less air at cruising speeds.

I'm a couple beers in at this point so don't take this as flawless info.

here's some thoughts

 

[GS ice T]

Mating a 4G63 head to a 4G64 block with forged internals will give you a compression ratio of about 9.7 as apposed to the usual 8.5-9 with the 2.0 setup. This on top of the increased stroke not only creates more power at a lower rpm but gives you TONS of extra torque.

I have this setup with a 20g which spools like a t25 on a 2.0. Full boost by 3k and hit peak torque by 4k and rev til 6.5-7k. The only downside I see to this setup is that since you need a built head to even make power past 7k you'll also need a built tranny thats geared longer too. In no time I can be in 5th gear at 7k rpm and maxed out at 160mph.

As far as crankwalk, I think they are no different than 4g63 blocks. I know of one case personally of a walked 64 block.

Another point that could be a pro or a con is the fact that since the compression is higher you will either have to run less boost or a less detonation proned fuel setup. I plan to try a 93/E85 blend to boost 20+ psi for spring.

 

[okm12346]

not necessarily. Usually 4g64 pistons are made specifically for DOHC head and the CR varies from 8.5 to 9.5. These pistons can be used with the SOHC head as well where the CR goes down with 0.5 to 8.0 to 9.0. If you paid attention when you browsed for pistons it says 4g64 with DOHC head have such and such CR.

 

[95patalon]

So basicly I shouldn't fall out of boost because i am making equal amount of power compared to a 2.0 shifting at 8000rpm compared to a 2.4 shifting at 7000/7500rpm

 

[BullseyeGSX]

I have a question .... where do you buy parts for a setup like this ? I've been to AMS, BUSCHUR, & SLOWBOY as well as STM and I haven't seen any mention of 4G64 Parts or G4CS. I'd love to do the 2.4 setup in my upcoming project but I don't know where to find parts for it.

 

[Tanro]

Oil squirters have nothing to do with crankwalk... It is the thrust bearing that was used in 95- early 97 7 bolts that caused the issues.

 

[jimbob_843]

Check out thedsmgraveyard.com Im doing the same kind of build and thats where i got my parts from

 

[RadDsm]

Oil squirters have nothing to do with crankwalk...

Oil squirters getting stuck open at high pressure definitely can have something to do with it.

 

[Jesse__c]

i have a built 2.3, fully built head. my t25 felt like it was spooled at idle. now i have a pte sc6175 that spools at about 4500rpm's on pump gas. the added torque is beautiful. and my mechanic is confident that my motor will rev to 8500 no problem. i have had it up to 7 or 8 grand and the power is there all the way thru. but believe me you will be puttin out some serious $$ unless you are a very talented mechanic.

 

[MidShipCivic]

Oil squirters have nothing to do with crankwalk... It is the thrust bearing that was used in 95- early 97 7 bolts that caused the issues.

Oil squirters getting stuck open at high pressure definitely can have something to do with it.

Stop spreading poor info this is why amateurs say this crap all the time. They do a search on google and the hits just catch crankwalk, then all of a sudden the have doctorate on the subject and swear on something that just has 6 bolts on the crankshaft flange.

It's an inferior motor really.



Any engine will walk from causes like excessive single disc pressure plates, failing oil pump, foreign objects in squirters or preloading dead stop launches on low quality engine oil.


I use a 94 Galant GS 2.4L 4g64 block in an original 6-4 DSM me stating this is very irrelevant isn't it ?