Bills 33 Gtst Streeter/track Car

[admS15]

On 28/09/2023 at 1:17 PM, Kinkstaah said:

The joke was Dose was attempting to sell his complete car, and I joined in too.

My gut feeling is to tell you to actually go RB30 if you get the head cleaned up. Never turn down an upgrade opportunity when something breaks... it makes it more bearable 😛

Yeah I got that but buying your car is definitely not K.I.S.S

 

Too many extra $ for RB30 extras required.

 

[Duncan]

RB30 is awesome, but it is not a quick and cheap way to get back to the track, there is a bit of stuffing around required due to block height (a little easier in 2wd, but still a pain)

[admS15]

Just been to an engine shop. Head is easily fixed. Guy wants to replace all 4 valves on the damaged cylinder to be sure. Couldn't say exactly how much it would cost without tearing it down but did say won't be much. I may get a 2nd opinion if I could be bothered.

Edit. Apparently the dent around the chamber won't matter but he could weld and machine it if I wanted.

[Duncan]

yeah, head jobs can be cheaper than you might expect

I would suggest getting that dent sorted though as pinging tends to start at irregularities

[Kinkstaah]

2 hours ago, admS15 said:

Yeah I got that but buying your car is definitely not K.I.S.S

How dare you, I've been through this pain so many times to make it as simple as possible lol.

I'd still think a RB30 is going to be as simple as a RB25 bottom end. Surely? Right? People lose their minds over a 200cc stroker. Why not 500cc?

This is gonna take more time and more money than you expect, no matter the option you go with. I reckon no matter what you do it's gonna end up being mid 2024 before it is running again. Why not do that with a 3L :D.

How much more _is_ it? Surely worth investigating.

[GTSBoy]

35 minutes ago, Kinkstaah said:

I'd still think a RB30 is going to be as simple as a RB25 bottom end. Surely? Right?

Yeah, nah. Everything attached to the head moves up. So turbo in and out + cooler pipework on both ends needs to be edited. Plus, on an R32 (not the case here, because R33) it's almost impossible to fit under the bonnet without doing undesirable things. A little easier on R33, but still.....stuff you have to do.

Edited September 28, 2023 by GTSBoy

[admS15]

On 28/09/2023 at 3:48 PM, Kinkstaah said:

How dare you, I've been through this pain so many times to make it as simple as possible lol.

I'd still think a RB30 is going to be as simple as a RB25 bottom end. Surely? Right? People lose their minds over a 200cc stroker. Why not 500cc?

This is gonna take more time and more money than you expect, no matter the option you go with. I reckon no matter what you do it's gonna end up being mid 2024 before it is running again. Why not do that with a 3L :D.

How much more _is_ it? Surely worth investigating.

The bottom end won't cost any more, will probably be a little cheaper as there are less expensive piston options for them if wanted. It's more the fact my turbo is not really big enough, will be an emap roadblock, injectors won't be big enough for the bigger required turbo. May as well get a decent exh manifold, custom dump pipe. You get the picture.

The replacement vanilla 25det is the best and simplest option but finding a good one for non drug money is another story. I enquired about a long block today and the bloke wanted 5k for it. Yeah, nah.

Fark, I almost feel like rage quitting.

As well as all the things GTSboy said

[admS15]

On 28/09/2023 at 3:44 PM, Duncan said:

yeah, head jobs can be cheaper than you might expect

I would suggest getting that dent sorted though as pinging tends to start at irregularities

Agreed on all

[GTSBoy]

38 minutes ago, Duncan said:

head jobs can be cheaper than you might expect

This excellent double entendre appears to have been missed by all.

[Dose Pipe Sutututu]

this guy wants $3k for a NEO motor, however says he has been sitting around for 7 years.

No idea, however maybe an option?

https://www.facebook.com/groups/JDMASf*k/permalink/3490884201171523/?sale_post_id=3490884201171523

[admS15]

Didn't miss a thing, I agreed on all points but sometimes a cheap head job is an illusion. Costs you dearly in the long run.

Anyway, I received some info today that the 25de neo head is 52cc.

@GTSBoy rough dirty calc time

25de neo 10.2:1 comp with 52cc head 

Where would it end up with roughly with

25det head with around 62cc head?

My rough head calculation says around 20% less. So around 8.2-8.3:1. Am I in the ball park or way off?

 

[admS15]

On 28/09/2023 at 4:39 PM, Dose Pipe Sutututu said:

this guy wants $3k for a NEO motor, however says he has been sitting around for 7 years.

No idea, however maybe an option?

https://www.facebook.com/groups/JDMASf*k/permalink/3490884201171523/?sale_post_id=3490884201171523

I did see that somewhere but quite weary of something sitting that long that looks like that 

[GTSBoy]

11 minutes ago, admS15 said:

Didn't miss a thing, I agreed on all points but sometimes a cheap head job is an illusion. Costs you dearly in the long run.

Anyway, I received some info today that the 25de neo head is 52cc.

@GTSBoy rough dirty calc time

25de neo 10.2:1 comp with 52cc head 

Where would it end up with roughly with

25det head with around 62cc head?

My rough head calculation says around 20% less. So around 8.2-8.3:1. Am I in the ball park or way off?

 

Meh. I dunno. I haven't got my old calcs with me here to know what I did for things like head gasket, etc. Those old calcs might not even exist, as I may not have saved them.

If I do a rough calc now (86mm bore, 71.7 stroke, 51.5cc DET chamber volume) and don't allow for the gasket gap (1mm, equivalent to 5.8cc at 86mm bore diameter), then the CR comes out to 9.1:1, which is spot on the "known" RB25DET CR.

If I do allow for the gasket gap on top of the 51.5cc chamber, then the CR drops to 8.25:1. So....does the gasket gap already get taken into consideration in the chamber volume? It looks like it might.

So, given that it might, and that when I neglect it, I get the exact right DET CR, let's just ignore the gasket gap and continue.

There's another factor though, which is the dome on the piston. The DET chamber is "known" to be 51.5cc, and if the DE chamber is "known" to be 52, then they are almost exactly the same, and could well be the same. In which case, the difference in the resulting CR between them has to come down to the size of the dome. The DE dome would be taller, and would result in a smaller effective chamber volume compared to the DET. (And the DET dome probably explains away the gasket gap problem).

So, given that I have no information on the dome sizes, we just have to work backwards from the 10.2: CR to work out what the effective DE chamber volume has to be. It will be smaller than 52. Just throwing smaller chamber volumes at the original calc, with no gasket gap included, shows that the effective DE chamber volume is ~45cc. That's 7cc smaller than the "actual, known" DE chamber size. So, subtract that 7cc from the 62cc of a vanilla DET head's chamber, giving 55cc, and then run that calc forward again with 55c, and...... CR pops out at ~8.6.

Your 8.2-8.3 is not that far away from what I got, but both calcs are likely full of crap. I would say somewhere between 8.2 and 8.6 seems very likely though.

[admS15]

Thanks very much @GTSBoy. It's a workable scenario. We'll see what happens.

[Dose Pipe Sutututu]

Or run the DE NEO head, (pretend I never said this) get a thicker head gasket to lower the CR to say 9 - 9.5:1 and send it.

[No Crust Racing]

5 hours ago, admS15 said:

May have to open an account 

Me too, rb25/30 would be nice but then would have to upgrade everything are it. Turbo, injectors etc. are all too small.

I am seriously considering this route, trying to arrange to go have a look at this particular motor.

The problem with this scenario is that the bulk of the $ is in the machining and parts. Wouldn't be saving all that much by assembling it but the chance of me messing it up would be too great. 

I'll send you the windowed block to practice on, 😂

When I say cheap I mean free my dude. 

Machining, 1-1500, parts, 1-3k? 

New motor. 

[admS15]

On 28/09/2023 at 6:10 PM, No Crust Racing said:

When I say cheap I mean free my dude. 

Machining, 1-1500, parts, 1-3k? 

New motor. 

Free motor, yes please. Please supply all parts (nitto only), machine, assemble and ship to me. 😂

[Kinkstaah]

6 hours ago, admS15 said:

The bottom end won't cost any more, will probably be a little cheaper as there are less expensive piston options for them if wanted. It's more the fact my turbo is not really big enough, will be an emap roadblock, injectors won't be big enough for the bigger required turbo. May as well get a decent exh manifold, custom dump pipe. You get the picture.

The replacement vanilla 25det is the best and simplest option but finding a good one for non drug money is another story. I enquired about a long block today and the bloke wanted 5k for it. Yeah, nah.

Fark, I almost feel like rage quitting.

As well as all the things GTSboy said

Just... lower the boost? There's no reason you really have to upgrade the turbo. Oh no, you have to set your rev limit to 6000 because you're making 315kw at 6000 now instead of 7500. Remember the size of the OEM turbo on OEM displacement? It doesn't magically kill itself the first time anyone revs it out to 7500rpm in stock configuration with stock boost either.

I haven't done the math (and I can't tbh) but I'd wager a RB30 with your highflow has a "bigger turbo" relative to it's displacement than a RB25DET has a non-highflow turbo.

Truthfully there's quite a few options here. I know what it's like to panic and get angry about it but there is no fast fix for this. So take time and think about where you want to end up and what you want to end up with. It's expensive now, but you'll actually be paying for this months after christmas most likely. There's time to save.

Your bottom end that is mentioned above, but 1-1500 for machining, and 1-3k parts, still getting near that 5k mark. Similar to old mate selling his 25det bottom end for 5k. Getting someone to assemble it obviously costs more and is only as good as who you trust to do it.

You also don't know if someone is going to sell a motor a month from now (for example). Take a step back, breathe, it happens. It sucks, but it happens.

[GTSBoy]

1 hour ago, Kinkstaah said:

Just... lower the boost?

There's ways that this logic doesn't work. If you lower the boost and still try to pump the same mass rate of air, then, depending on where you were on the compressor map originally on the smaller motor, you can find yourself wandering right over to the RHS of the map and giving up 15% or more efficiency. Start pumping hot air, overspeeding, etc etc.

This is the same concept as the couple of posts in other turbo threads where a turbo that was expected to go real well didn't, on 3L and 3.2L engines. Just not a good match because of the shape of the comp map.

[admS15]

Engine block is ready to come out. Hopefully get some time later today or tomorrow morning.Gearbox will remain in the car for now. PS and AC pumps have both been unbolted and tied off to the side.

Anyone see any issues with trying to get the replacement engine back in (when I get one) with gearbox in situ?  Is it doable or a major ball ache?