RobPhoboS

Hey guys, little bit of background:

I did my valve stem seals, cams (JWT C8) and timing chain stuff over Christmas in my tiny freezing cold garage (I loved it!).

Have a look here if you want to checkout what I did:
https://www.350z-uk.com/topic/122458...stiming-chain/

I did this mainly as I'm enjoying working on the car myself, I like learning and haven't done anything like this before.
Sure, getting a few more ponies is cool but isn't the prime goal.
The main goal is to build an engine that can deal with regular track days for a long time to come !
I'm not Sasha, so I can't be building a 500+bhp monster

I'll be fitting a set of JWT spec'd PPE LTH's soon, and will get another remap before doing the bottom end.
I'll buy the parts in the next few weeks but won't be fitting the guts of it just yet.

Now, had I known that I was in a position to be able to get the bottom end stuff, of course I would have waited I really hate all of that sealant !
The car was burning oil, so I knew it was a combo of the rings and stem seals.

Another friend here in the UK has done a similar build with an HR, he chose CP pistons, 96mm, 12:1 with the following options:
X-Forging
Anti det grooves
Skirt coating
Crown coating
9310 steel pin

I also emailed Ben at JWT to see what he'd recommend as well, I know they use JE pistons.

Anyway, any specific advice on these bits and pieces would be great !


Note:
Over here our octane rating is measured differently to you guys, so my 98 RON Octane x 0.95 = 93.1 AKI Octane (USA) (iirc)
I'll also order Boundary Engineering oil pump gears for my rev-up oil pump, and yep of course head/block work.

dkmura

iTrader: (64)

In a NA application, the VQ could really benefit from a good set of high-compression pistons. Since you're in the UK, any chance you can get Cosworth components for less than what they cost here in the US? You'll want to tune on race fuel, however and I'm curious what 100+ octane fuel costs over there? As I'm getting ready to start my race season here, I'm seeing unleaded 100 octane unleaded running for 8.50-12.80/gallon. Knowing what the usual costs of petrol were the last time I visited Europe, I can only imagine what it costs now!

RobPhoboS

Hey dkmura !

Sadly I'm not sure about Cosworth, their website is utter tosh, completely useless marketing nonsense with no proper catalogue that I can see. And I don't know anyone that sells their pistons specifically
My car gets used during the week (100ish miles typically), and throughout the whole year. So I'd rather run it on pump fuel, sure maybe at the track put a little race additive in there but only if it has been tuned for that I imagine.
Yes you're correct, fuel here is extremely expensive due to our government taxing the crap out of everything !
Race fuel is available at some of our tracks but it's about £3 per litre !!! (3.7854ltrs per gallon)
So that option is NO

I have emailed the guy that does my tuning here, just to see what his thoughts are.

dkmura

iTrader: (64)

Without high-compression forged pistons and the accompanying 100+ octane fuel to control detonation, your gains will be limited. But freshening the bottom end will help, and a good tune will likely result in some modest gains on 91-93 octane fuel. Too bad you don't have a baseline dyno to compare anything to. If you'd like, I can provide data for my baseline from when my '03 preorder DE was new.

BTW- in comparison to your costs on race fuel, our costs here in the states is only about 25-30% less. Regular pump fuel, as you know, is considerably less that that.

RobPhoboS

I guess what I was inferring to was this:
Is there going to be much of a difference between 11:1 & 12:1 ?

I do have dyno's at various places but I only tune at one place.
The numbers are totally meaningless to me, and there seems to be quite a difference between us over here and you chaps. My only concern is that it's makes an improvement (especially in the areas that I want) rather than some silly goal of a number.
Did you want an image of one ? (it's on my link in the first post).

Strange, I thought your race fuel would be a LOT cheaper !

I also just noticed the fuel I always use is 99 octane here (so your 94 I think).

Conway_160

iTrader: (1)

I was dyno'd at 280Whp with 11:1, bc stg 2 cams, long tube headers, kinetix velocity plenum, injen long cia, on 93 oct in my 04 g35. The power can be made its just expensive.

03threefiftyz

iTrader: (25)

My experience on these motors has not mirrored this fwiw...

...in fact, in a lot of circumstances, all things being equal (similar friction rings, piston weights, etc) the power gain from 10.1-12.1 is nominal even with somewhat larger cams. The money is better spent on optimizing the in/out flow on the peripherals (intake/exhaust path). In fact, the motor in my car now is a factory long block with the exception of rev-up rod bolts, king bearings, and a different oil pump. On C8/C2 it consistently rolls 320whp+ on NASA dyno's (E85). I have some things underway to bring that number closer to 335-338 peak (though flattened back down to around 320 to be NASA ST/TT3 legal).

RobPhoboS

I completely agree about the breathing aspect (inc cams of course!), which is exactly why I'm dealing with that otherwise the cams are sort of pointless.
We definitely need to optimise for them so they can sing how they intended to. That part isn't overlooked by me at all, and I've read through many, many posts where others have gone before me

I think it's why I said that I'm doing the bottom end to largely reduce the oil burning (which is massively reduced now with the new stem seals), and to strengthen it for higher rpm work and longevity.
Of course that can help get a few more ponies.

BTW I'd advise you not to pay too much attention to our (US/UK) dyno differences. You guys already know there is a disparity between the same model, let alone the operator/tuner. I know that the one I go to reads lower than 3 others I've visited here in the UK but I don't care about that. Just that we're making improvements when we can

03threefiftyz

iTrader: (25)

Yes, but the whp (NASA) will be relatable to dkmura since he dabbles in the same series....although they can differ much to our unhappiness. My car has probably done 500+ dyno runs in the past 8 years....every brand, type, etc and of course there is a variance.

jellofuel

I think the testing Sasha did showed that bumping the compression up didn't result in the expected gains because the DE plenum was so restrictive. I suspect (read: uneducated speculation) that as you make the intake manifold more effective or efficient, there could be small marginal improvements in performance with raised compression. I don't feel like I'm explaining my idea well, but for example, if you were to hypothetically bump a bone stock z up to 11:1, the gains from the increased compression ratio would be tiny.

But if you were to install a plenum spacer, making the manifold more efficient, the gains from the increased compression ratio would be slightly less puny. My overall point being, that raising the compression to 12:1 would have a significant impact on a z with an intake/exhaust system that's as free-flowing as possible. This doesn't seem to line up with what 03threefiftyz says though, so I'm unsure, and will heartily concede my post as wild speculation lol

Honestly, I doubt it would hurt, and hey, sounds totally BA. I'll ask the guys at Z1 next time I swing by for anything. I live 20 minutes from there, so pick up maintenance items on a normal basis.

RobPhoboS

I appreciate your input!
Our set up is very similar, I'm just waiting on the Z1 intake (same as yours), and the Kinetix is due soon but on backorder here (same with the ppe).

I'll probably stick with 11:1 as its more off-the-shelf, and likely to go with CP pistons at this point.
I'll see what the damage is soon with prices!

onevq35de

Read this thread to get the most of your NA build.
https://my350z.com/forum/intake-exha...intakes-6.html

Get the intake "neck" turned toward the battery box & relocate the battery to the rear.
Get a 75mm or larger throttle body and a 4" or 5" intake pipe with the pipe fitted into what was the battery box but now is the air filter box.
Insulate the pipe.
Make a (large) provision for air to enter the new air box.
Use the stock plenum + spacer and bore out the neck as much as possible before welding it back on (to be facing the battery box) or a Velocity manifold and do the same - boring.

Major pressure loss reduction via an extremely short but large diameter intake pipe (short ram), air box (old battery box) sealed off from the bay (cold air), a reduction in the degree of the bend in the intake plenum's neck (major restriction reduction)

With the above + lth's + cams, and any reduction you can get in accessory losses, I believe you'll have a record braking n.a. build.

RobPhoboS

I did, and commented some weeks ago

On this thread, as the title suggests I was looking more for advice on specific bottom end engine components (not to say your advice/thoughts aren't welcome just slightly off from what I was drilling down to - i like what you did!).

Remember I'm in the UK, my battery/brake is the opposite to you guys
I don't know if you read my first post but I'm not trying to squeeze every spec out of it, it's reliability but optimised for the cams of course, so what you suggested may well be a great option.
I was going to make something like what 350Z247 did on youtube but for now will settle for the Kinetix (if they ever send it out!).

bealljk

iTrader: (13)

subscribed -

onevq35de

Yes, I read it. I would argue that per some of what's been written above, a higher compression would be more along the lines of attempting to get every spec out of it in that unfortunately there is little to gain from such an endeavor and at a substantial cost. If the bottom end is still in tact, leave it be and have fun with it until a build is necessary. For now, I would concentrate on getting back lost horsepower, lost due to the inefficiencies of the intake and exhaust, as well as heat management.
I suppose my posts are not exactly what you requested but instead an attempt to get you to bring my idea to fruition and save you some trouble in the process.

RobPhoboS

Well I did end up doing what dkmura had originally suggested
I found a set of Cosworth pistons/rings/pins going for a very good price over here, so the rest of the parts I will still need to sort out.
I found out that Cosworth have stopped making these aftermarket parts, thus no info on their site etc

The PPE's are in, and a remap coming on the 6th.
I had a remap after fitting a Kinetix Velocity + Z1 'race' intake, however my power dropped a bit, so I'm hoping that the power comes back now that the LTH's are in.
I will take along my old upper/lower plenum + spacer if we're still not seeing good results.

RobPhoboS

Getting ready to order the other bits and pieces, except for the bearings as I'll need some info from the machinist about that.

Brian Crower Intake / Exhaust Valve Set Nissan (BC322x) (standard sized, I like that they're undercut)
Manley Sport Compact Steel H-Beam Connecting Rods (14019-6)
Ferrea Bronze Valve Guide Set, Stock Size (VG1038-VG1040-KT)
ARP Main Stud Kit (202-5801)
ARP Head Bolt / Stud Kit (202-4701)
King Engine Bearings Thrust Washer (TW271AM) (guessing I'll go with King bearings)

+ the billet gears for the oil pump
Cosworth 96mm HG on the way too.

I'm not sure about the ARP studs, are they ok for this kind of build ?
I know some people prefer TTY bolts/studs but I don't know how good the DE ones are, I think the HR ones are a little bit longer (3mm iirc).

Cheers for any help.

bealljk

iTrader: (13)

I would get the ARP L19 headstuds no matter what. It's worth the money. Lifted heads will ruin your weekend.

I'd also look into Dynostys billet girdle - smart money to stabilize the bottom end as much as possible.

RobPhoboS

Parts should arrive next week (photo's to come of course).
I'm a fair chunk through dismantling my engine now, in situ due to space - hah.
Rebuilding I can do inside my place after the machining but this part I have to do in my tiny garage

bealljk

iTrader: (13)

I did my rebuild inside my place … I have a large hallway between the living room and garage and it was significantly cleaner than my garage.