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Search found 186 matches

by BLSTIC
Sun Sep 12, 2021 8:34 pm
Forum: Engine Tech
Topic: Ram induction question
Replies: 11
Views: 552

Re: Ram induction question

Longer tubes does result in lower tuned frequency. But there are several harmonic lengths available for any particular RPM. The shorter ones have the wave traversing more times than the longer ones. You may be looking at a length where Chrysler product works on the 4th* harmonic, but if you lengthen...
by BLSTIC
Sun Sep 12, 2021 8:27 pm
Forum: Engine Tech
Topic: Porting With an Electric Die Grinder
Replies: 26
Views: 885

Re: Porting With an Electric Die Grinder

I used a Makita *Battery* one for a turbo adapter. The nature of the tools available to me at the time meant I had to go from a 38mm hole to a T3 flange, twice.

3/10 Would not recommend. Car went really fast though...
by BLSTIC
Sun Sep 12, 2021 4:20 pm
Forum: Engine Tech
Topic: Exhaust Duration, Boost and Elevation
Replies: 19
Views: 390

Re: Exhaust Duration, Boost and Elevation

A vaguely related question here: Say I had a turbo blow-through carb engine with a turbo that could come on boost before the stall converter, so it's effectively always on boost at full load... If I set it up so that it ran 5psi at sea level (for 20psi-ish absolute) and at 6000ft I run 8psi (ambient...
by BLSTIC
Sun Sep 12, 2021 6:53 am
Forum: Engine Tech
Topic: Exhaust Duration, Boost and Elevation
Replies: 19
Views: 390

Re: Exhaust Duration, Boost and Elevation

Controlling boost to compensate for high altitude requires keeping the plenum absolute pressure the same, not the gauge pressure. This will usually eventually lead to a turbo overspeed case so you need to also measure turbo speed to open the wastegate to control turbo speed when you get to the limi...
by BLSTIC
Sat Sep 11, 2021 7:18 pm
Forum: Engine Tech
Topic: Exhaust Duration, Boost and Elevation
Replies: 19
Views: 390

Re: Exhaust Duration, Boost and Elevation

With a Turbo, or a blower, the engine doesn't know it's at high altitude. It only knows the "Altitude" in the plenum. You would cam them the same way you would at sea level. If the pressure in the plenum is 46", that's what the engine sees. Would the lower pressure seen in the exhaust system at alt...
by BLSTIC
Sat Sep 11, 2021 3:32 am
Forum: Engine Tech
Topic: Running an LS lean of peak at WOT?
Replies: 27
Views: 951

Re: Running an LS lean of peak at WOT?

You say you're "limited on power"

Can you expand on that? Is it a dyno run on race day, a fuel flow limitation, a restrictor plate? How are you limited?
by BLSTIC
Mon Aug 23, 2021 4:21 pm
Forum: Engine Tech
Topic: Header primary diameter for a small motorcycle engine
Replies: 31
Views: 1813

Re: Header primary diameter for a small motorcycle engine

. 2 stroke expansion chambers are regularly formed from 2 flat profiles with lightly flanged edges welded and pressurised*. *With water of course, never air. But I like the risk of death... Also, home water blasters can probably provide appropriate pressure for this. Air compressors - not so much.
by BLSTIC
Fri Aug 20, 2021 6:50 pm
Forum: Engine Tech
Topic: 13100 rpm fourbanger restricted to 9300 redline
Replies: 102
Views: 4132

Re: 13100 rpm fourbanger restricted to 9300 redline

I'd be looking at the rear axle then, and any bearings supporting it. If it's mounted like a go kart and the bearings that support the axle aren't designed to operate at an angle anything bent will stress the bearings a lot. Also if it still uses a chain drive, there's a lot to say about efficiency ...
by BLSTIC
Thu Aug 19, 2021 11:43 pm
Forum: Engine Tech
Topic: 2.0L MZR header and exhaust length testing
Replies: 24
Views: 998

Re: 2.0L MZR header and exhaust length testing

If you break Calvin's numbers out by CSA against horsepower, it actually scales to be about 38-40hp / square inch across the board. I noticed this about 7 years ago and posted it here, but like a lot of things, it went over most people's heads. I put his chart from Exhausting101 into a spreadsheet....
by BLSTIC
Thu Aug 12, 2021 8:11 pm
Forum: Engine Tech
Topic: Straight vs Merge Collector
Replies: 43
Views: 1919

Re: Straight vs Merge Collector

I can't help but think that "anti reversion" is more "anti pulse" than "anti-reverse flow". Which is fine by me, if it works it works. If my mate ever gets his cruise wagon back on the road (it's purely designed to look and sounds badass, actual performance is entirely incidental) I'll see if he'll ...
by BLSTIC
Thu Aug 12, 2021 7:25 pm
Forum: Engine Tech
Topic: Direct Injection Video
Replies: 1
Views: 224

Re: Direct Injection Video

GDI Injectors are still flow and range limited, and they only have the intake and part of the compression stroke to inject fuel, unlike port injectors which can just be always on if there's need. Port injectors don't need to inject through an open valve. This limited window of fuel flow is also a li...
by BLSTIC
Sat Jul 31, 2021 4:28 pm
Forum: Engine Tech
Topic: Projected-tip spark plug benefits?
Replies: 34
Views: 1789

Re: Projected-tip spark plug benefits?

Slightly Off Topic, have these been shown to have heat shedding problems?
by BLSTIC
Sat Jul 31, 2021 6:51 am
Forum: Engine Tech
Topic: Projected-tip spark plug benefits?
Replies: 34
Views: 1789

Re: Projected-tip spark plug benefits?

A projected tip effectively advances the timing by several degrees, so optimum advance should be reestablished after a change from one to the other. Or would it be more like moving to a chamber that requires less advance? Probably some combination. Anyway I noted the Mercedes M139 engine (that appe...
by BLSTIC
Tue Jul 27, 2021 7:43 pm
Forum: Engine Tech
Topic: Principles of exhaust design!
Replies: 4
Views: 458

Re: Principles of exhaust design!

Also a complete amateur but with lots of theory. A lot of exhaust tuning comes down to "do no harm". Keeping joining pipes at least [exhaust duration] degrees apart avoids blowdown interference (blowdown pulse messing with overlap when exhaust valve is still open) but on a cross-plane V8 that's kind...
by BLSTIC
Thu Jul 22, 2021 2:56 pm
Forum: Engine Tech
Topic: 13100 rpm fourbanger restricted to 9300 redline
Replies: 102
Views: 4132

Re: 13100 rpm fourbanger restricted to 9300 redline

I'd start by altering the crankshaft gear and tdc indicator so that any degree wheel read correctly to spec but the crankshaft was actually where i wanted it It's like here in Aus Cleveland engines would oil starve and they weren't allowed to drastically overfill. Tech supposedly had a standard dips...