Don Terrill’s Speed-Talk

Just ran across this topic researching something else. Is this practice accepted or a way to sell bs....removing quench pads and redoing chamber via cnc. Sometimes I get the impression that if the modification doesn't hurt performance it can be spun as if it increased it- is this a flavour or does it work?

Standard answer - it depends...

Here is a pretty solid video from a well respected time attack team running an RB. No reason for me to doubt what he is saying (no RB hands on experience)

https://youtu.be/nrZm3xGlXQM

(lots more than you asked, but you question is addressed specifically there)

Good vid, thanks.

The RB is one of the best engine series ever, whether the RB30 with RB25DET heads/cams or the GTR RB26. Here is a dyno of a local one with one of our local guru's custom made 6868 turbos (single). Most folk making this kind of power from an RB are turning serious rpms, this one is making 150rwhp as low as 3000rpm (very good for a little straight 6) with full boost by 4200rpm. This is only a 23psi pull. A later pull saw nearly 1000rw at 26psi but out of injector and is expected to make 1200 crank hp around 30psi when they get more injector... on ethanol. If anyone knows these engines, this is a good TQ curve for the little 6.

Curtis Mc wrote: ↑Tue Apr 09, 2019 7:05 pm Standard answer - it depends...

Here is a pretty solid video from a well respected time attack team running an RB. No reason for me to doubt what he is saying (no RB hands on experience)

https://youtu.be/nrZm3xGlXQM

(lots more than you asked, but you question is addressed specifically there)

Awesome video - and awesome to see an engine builder being so honest and informative on video. Top marks getting it to run up to 2 track times a day at 90 seconds each at that power and rpm.

An interesting point would be is it the 35psi that hates the squish pads in the head or the 10,000rpm?

My LS3 runs 13.7psi on pump gas at 11:1 static and a small high cylinder pressure cam largely because it has a tight squish. But what works at 6500rpm has little relevance once you get to 10,000. Hence I love how the Kiwi RB motor looks set to make 1200 under 7500rpm, that'd be so much easier on parts.

Bazman wrote: ↑Wed Apr 10, 2019 5:20 pm An interesting point would be is it the 35psi that hates the squish pads in the head or the 10,000rpm?

Exactly! Hence the "it depends"

Is it the fuel, IAT's, 4v, valve angle, RPM, etc...??? Certainly a well sorted combo. I look at some of the elite turbo drag cars on methanol, no intercooler. I believe most of that is due to the fuel, but there are other factors at play here too that moved the elites in that direction.

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if your making power lower then ultimately your making more tq and for a decent power band your making much more tq lower down therefore is this not far harder on parts as oppose to low tq and high rpm
, the squish pads removed i believe use also be run in the jap gt500 gtr's for racking ,
i removed them when struggling to make power on week fuel 10yrs ago couldn't do back to back but managed 760 on Uk pump fuel which is better than ours , but for a run of the mill build i'd leave them

I don't think 'billet block' and 'economy/emissions' can be applied to these guys in one sentence.

dfarr67 wrote: ↑Thu Apr 11, 2019 10:10 am I don't think 'billet block' and 'economy/emissions' can be applied to these guys in one sentence.

Lol, well if economy and emissions are at all relevant leave the squish pads there.