RallySport9

iTrader: (20)

You make valid and true points, and for a car not doing many miles/track, drag only. I myself would feel comfortable driving without them. I'm not saying it's gona destroy your car immediately. I just don't believe it's false to say that secondary vibrations cause other long term issues. How is that possible? If the vibration is enough to back out bolts, that's pretty significant.

Spooled_IX

I just picked up a used Tanabe 2.75" DP, Ultimate Racing 3" HFC and a AEM X-series WB. The car already has a Blitz FMIC, Nisei LICP and HKS Super Turbo CBE and I need to find a way to get a Grimmspeed 3-port BCS and OmniPower 3-bar MAP sensor to CA so I can start tuning it. I'm sort of following an FQ360+ build sheet so I'm hoping to get about 300whp/300wtq on 91 with all of these mods. I've driven a stock Evo 9 for 2 and a half years and it's time for some more power and response. You guys think this is doable on 91 and stock injectors?

LetsGetThisDone

iTrader: (1)

You only need the right frequency to back out a bolt. Doesn't have to be severe.

Construct

iTrader: (4)

300whp on stock injectors and 91 octane around sea level shouldn't be a problem. People have posted dyno sheets with even higher numbers from different dynos.

I'd recommend not aiming too aggressively for specific numbers. See what you get and then back off a little bit for some added safety margin. These cars are fun with the stock turbo uncorked.

ViciousLSD

iTrader: (2)

I wish that was my experience

Bee-Raddd

has anybody toyed around with upgrading to 1/2 head studs rather than going down the o ring route? or if youve gone down the o ring route have any of you done the head side rather than the block side?

If you have L19 studs how far have you pushed them?

TimC909

What HG are you using now? I quite like the look of the SCE Vulcan Cut-Ring gasket but not seen much feedback from it on the 4G63.

Dallas J

iTrader: (1)

Isn’t there issues to be solved with the deck being not stiff enough to tolerate more torque from bigger head studs?

Bee-Raddd

Ive always just stuck to stock HG to be honest. seen theres some fancy ones around. heaps of options now which is why im stewing over what to do while the head is off

You can buy shouldered dowels now and have them installed which allows you to torque down more. This is another option even on standard head stud diameter.
As i understand it the main issue is generally the boost level presses into the head and the material around the nut/washer compresses causing the head to lift off the block.

https://www.tmzperformance.com/shop/...ldered-dowels/

LetsGetThisDone

iTrader: (1)

Just oring it. 1/2" head studs are a headache for 1000whp+

Block or head, take your pick. It's all works well. L19's torqued to 100ftlbs with the oversized nut and .9" washers and oring will hold a lot.

Ayoustin

iTrader: (2)

Oversized head studs aren't worth the effort. Grab some 625+ studs and call it a day. With o-rings those will hold 1000+.

I generally avoid L19 just because of how corrosion prone the material is. It's a fairly exotic tool steel and when tool steels like it corrode they form weak points in the corrosion and the material doesn't stretch, it snaps.


Depends on who you talk to. The deck on a 4G block isn't crazy thick but still thicker than most. But clamping force is clamping force, whether you get it from stronger materials or larger fasteners, they both deform the deck after a certain point. The bigger issue than block deck thickness is how deep, or not deep, the studs thread into the block. The threads aren't that far below the surface of the deck which forces the deck to deform more easily. If you look at most modern engines the fastener threads for the head fasteners are a good 4-6" below the surface of the deck and aftermarket head studs are like twice as long as 4G head studs. This is where being an iron block is advantageous because it'd be far worse if the threads were this close to the deck in an aluminum block but the principles still apply. Unfortunately I don't think the head fastener threads can be made any lower in the block without breaking into the crankcase.

I recall watching an HPA interview with an engineer who was involved with RX cars that were 4G powered and were making some insane torque at lower RPM and the only way they could keep the deck of the block from flexing was basically adding a thicker deck plate between the block and head.

Edit: here it is

Bee-Raddd

Are the oversized nut's the ones that come with the L19s or is that another upgrade? I guess the question is do i need to o ring if i have the L19 studs. i only want to make max like mid 30psi boost for short periods of time.

Yea maybe i should be looking into uprated head gaskets to go with the L19 studs i already have rather than using the factory gasket.

dr_latino999

iTrader: (12)

Define not many miles on the subjective clause? I'm on a decade here of daily driving, from cross country American road trips, to enjoying the German autobahn network, and tourist days at the ring. I think I've put my drivetrain through almost every scenario short of artic winters.

ViciousLSD

iTrader: (2)

summer project ugh
sadly, i got forced into rebuilding my current motor a bit too early, was planning it until after that nats. so this is the buschur 2.0 short block package, built 2019, didnt race during the pandemic, so I got 1.5years of autox + 2 lite time attack days *sigh*. oil pump was new, changed brad penn oil frequently and it doesnt smell e85. i got a spun #4 rod bearing... is 8200rpm rev limit the culprit here?

LetsGetThisDone

iTrader: (1)

No, the #4 rod is the last to get oil. Likely a starvation issue. Post pics of all the bearings. I'm sure the others show evidence of starvation as well.