PRP RB26 cast block + head prototype running

[MBS206]

22 hours ago, niZmO_Man said:

Something to keep in mind, RB26DETT was dreamt up in 1986-1987 for the Group A regulations. So to compare it to a post-2005 engine is not the best.

You must Compare the RB26DETT to its contemporaries, like the YB (which it killed off), the 1GG, 1JZ, whatever 5L V8 Ford/Holden had, etc. etc. aka late 1980's tech.

When you're trying to match RB26 to a S58, you've gone off the deep end already and are looking at custom block/head/etc so no longer a standard engine.

Technology has come a long way from 1990 to 2020.

It makes you wonder, all these people starting to make a billet replacement head, I wonder if any have thought about trying to adapt tech from newer engines into them.

You're already at the full design stage to make a billet head... Why not really spice it up and had some more modern tech into the mix too...

[r32-25t]

Because that’s not what any of them are building these heads or blocks for. It’s to hold over over 1000hp at the wheels without breaking and none of that stuff is required to make power 

[Dose Pipe Sutututu]

I've seen tunes from big name workshops with cars making in excess of 700kW and one thing that stood out to me, is that noone is bothering with torque management.

Everyone is throwing in as much timing as the motor can take for a pull.

Sure that yields pretty numbers on a dyno, but it's not keeping these motors together for more than a few squirts down the straight without blowing coolant or head gaskets.

If tuners, paid a bit more attention and took timing out in the mid range, managed boost a bit better, you'll probably see less motors grenading.

Not to name names, or anything like that, but I've seen a tune, from a pretty wild GT-R from a big name tuner and I was but perplexed on the amount of timing jammed into it. You would have expected a quite a bit less timing at peak torque versus near the limiter, but there was literally 3 degrees of difference. Sure you want to make as much as possible throughout the RPM range, but why? At the expense of blowing motors?

Anyhow I think we've gone off topic enough once again lol.

[joshuaho96]

25 minutes ago, r32-25t said:

Because that’s not what any of them are building these heads or blocks for. It’s to hold over over 1000hp at the wheels without breaking and none of that stuff is required to make power 

It's not, but it does feel like a bit of a missed opportunity regardless. For example, what if the cylinder head was redesigned to fit a GDI fuel system? It's worth like two full points of compression ratio when looking at modern GDI turbo vs PFI turbo. I'm pretty reliably surprised at how much less turbo it takes to make similar power out of a modern engine vs something like an RB26. Something with roughly the same dimensions as a -7 on an S55 is making absolutely silly power numbers compared to an RB26. I know there's a ton of power loss from things like high tension rings, high viscosity oil, clutch fan, AWD standby loss, etc but it's something like 700 whp in an F80 M3 vs 400 whp in an R33 GTR. The stock TF035HL4W turbos in an F80 M3 are really rather dinky little things and that's enough to get 400 whp at 18 psi.

1 minute ago, Dose Pipe Sutututu said:

I've seen tunes from big name workshops with cars making in excess of 700kW and one thing that stood out to me, is that noone is bothering with torque management.

Everyone is throwing in as much timing as the motor can take for a pull.

Sure that yields pretty numbers on a dyno, but it's not keeping these motors together for more than a few squirts down the straight without blowing coolant or head gaskets.

If tuners, paid a bit more attention and took timing out in the mid range, managed boost a bit better, you'll probably see less motors grenading.

Not to name names, or anything like that, but I've seen a tune off a pretty wild GT-R from a big name tuner and I was but perplexed on the amount of timing jammed into it. You would have expected a quite a bit less timing at peak torque versus near the limiter, but there was literally 3 degrees of difference. Sure you want to make as much as possible throughout the RPM range, but why? At the expense of blowing motors?

Anyhow I think we've gone off topic enough once again lol.

This just seems unwise no? I thought the general approach is if you aren't knock limited the MFB50 should be held constant through the RPM range. So more timing with RPM, but less timing with more cylinder filling. A VE-based table should accordingly inverse the VE curve of the engine.

[r32-25t]

Because people who want that are buying euros. The people with the money to buy the aftermarket heads and blocks aren’t interested in efficiency or making -7 power, they’re making well over 1,000hp and pretty much only drive them at full throttle 

best way to way make money is know your customer base and what they want and don’t spend money making things they don’t want. 

[Duncan]

16 hours ago, r32-25t said:

Because people who want that are buying euros. The people with the money to buy the aftermarket heads and blocks aren’t interested in efficiency or making -7 power, they’re making well over 1,000hp and pretty much only drive them at full throttle 

That's how it seems to me to. For the people that want huge power RBs (which it has been shown to do), this is great news, but that is not the same as trying to bring an rb 30 years forward....its not clear that there is a market of people who would pay 10s of thousands to do that

[r32-25t]

There’s probably people who’d like to do it and then when it comes to putting their hands in their pockets they’ll all disappear into the shadows 

[joshuaho96]

23 hours ago, r32-25t said:

There’s probably people who’d like to do it and then when it comes to putting their hands in their pockets they’ll all disappear into the shadows 

Maybe, but HKS' laughably expensive advanced heritage intake system (1.5M yen, listed by USA dealers at 15k USD) was sold out almost immediately and I'm not sure they ever re-opened orders for it. That's the kind of money that gets you a new block and head these days and people are spending it on benefits that boil down to "the twin turbos aren't quite as garbage as before".