How Strong is the 4G63 SOHC? How much POWER???

Post by **TOMSUN** » Mon Oct 25, 2004 9:37 am

How much power will the 4G63 SOHC take?
I've been told the VR4 block has 4 bolt mains as opposed to 2 bolt in the Starion...

Max power with...??
1. With standard pistons and rods?
2. With evo or hypereutetic pistons and VR4 rods?
3. With forged pistons and custom rods?

decoy · Post by **decoy** » Mon Oct 25, 2004 1:06 pm

1: 1bar
2: 1.25bar
3: 1.5bar

CussCuss · Post by **CussCuss** » Mon Oct 25, 2004 1:49 pm

i hope to find out over the course of the next 6 months or so how much power it will take with standard pistons and rods, they are pretty strong supposedly.

Post by **TOMSUN** » Mon Oct 25, 2004 1:49 pm

hmm???? Decoy...
Is that just your impression or have you had experince with these things?

I can see that piston strength is related to boost but what about...

RPM... I thought that rpm would be the biggest factor for rod strength?
What would the standard rods and bolts be good for as far as rpm is concerned???

And the combination of the boost with the rpm would influence the strength of the main caps and crank...???

Glenjo · Post by **Glenjo** » Mon Oct 25, 2004 2:15 pm

I have been for a spin in a 205RWHP JA running standard pistons. MPI, cooled etc etc btw.

NXTIME · Post by **NXTIME** » Mon Oct 25, 2004 3:39 pm

Forged pistons and shot peened rods = 20psi thru a 60mm TO4 so far. Std cam, L300 intake and exhaust manifolds. 211rwhp@4300rpm with more to come.

CussCuss · Post by **CussCuss** » Mon Oct 25, 2004 4:37 pm

ive been told that no matter how worked and strengthened they are if you go much past 6k you will still break things. Apparently the group A starions ran about 1 bar with no cooler (race fuel of course) fine but still didnt rev em hard.

quest · Post by **quest** » Mon Oct 25, 2004 10:44 pm

1ST gen dsm = vr4 to u guys
I understand, from bishiboys and this site, the internals are interchangeable and the head is a bolt on. I have all the parts, but not yet verified it. I see no reason that a staz can't withstand 350Whp on stock pistons/rods. I seriously doubt the casting method or material is that much different, or at all betwwen the two. Folks in the u.s. regularly make 400whp+ on stock 7.8:1 1st gen and 8.5:1 2nd gen stock cast pistons. sohc rods are very beefy too.

I'd run like hell from hyperutectics... even if they were free.

How much power will the top end make ? I figure a simple phone call to coltspeed could answer that too. Wasn't there a site fearturing a VERY NICE 300whp sohc car - a well tuned mpi is mandatory.

They way to get power from these motors seem like some deep dark secret

Post by **TOMSUN** » Tue Oct 26, 2004 7:57 am

Interesting posts...

Well being on a very tight budget I've decided to run an
RB25 turbo on a stock 2L SOHC with MPI Sonata w. VN Throttlebody and a Modified VN computer and some other bits and pieces

Run it to a max of 14psi and rev it to 6,000 plus and I'll let you guys know how much power it makes before she goes bang...

Then look out for the WTB... Post in the Buy & Sell forum rofl

nashstyle · Post by **nashstyle** » Tue Oct 26, 2004 8:47 am

SOHCs ping on anything after 15psi on 98RON.
There is a soft rev limiter at 6500rpm so up to there you're not going to break anything.

Post by **TOMSUN** » Tue Oct 26, 2004 8:53 am

nashstyle

What amount of timing do they tend to ping at with 15psi? (and using 98 RON)

nashstyle · Post by **nashstyle** » Tue Oct 26, 2004 9:45 am

Ummm cant remember what mines set to :? I think 6 ATDC???

Post by **TOMSUN** » Tue Oct 26, 2004 10:32 am

That would be your static timing but there should be a fair bit of advance when you get it moving... maybe 25 to 30 degrees advanced or more at mid rpm and mild load etc...

We ran a stock 180sx turbo on the dyno last night. it made a whopping 74kw@rw. We check the timing and it was on 10deg @ idle. It was advanced another 5 degress to a total of 15 degrees advanced at idle and did another power run. This time it made a more respectable 96kw@rw. It's amasing what a bit of timing will do (Instant 22kw@rw) :D

And to avoid pinging back the timing off a bit even if it is at 15psi and on 98 RON (just loose a bit of power with less timing)

nashstyle · Post by **nashstyle** » Tue Oct 26, 2004 10:43 am

Yeh thats what happened when my last engine was dyno tuned, they found that a few degrees further advanced running 14psi was making more power than 15psi with less timing. Hopefully when I get my new engine to stop missing I'll get it re-dynod tuned.

Barney · Post by **Barney** » Wed Oct 27, 2004 12:41 am

I am after 240 rwhp and will find out next week when it,s tuned. How long it lasts if a different question. The Turbo thats i have fitted is good for 320rwhp the only thing thats stopping me is the standard pistons. :(

Austarion

How Strong is the 4G63 SOHC? How much POWER???

How Strong is the 4G63 SOHC? How much POWER???

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