We are currently running on the new domain and server: www.Speed-Talk.com

IMPORTANT: Update your bookmarks to https://www.speed-talk.com/forum/
(Right-click the URL and select "Bookmark this link")

Search found 37 matches

by BLSTIC
Thu Dec 05, 2019 6:41 pm
Forum: Engine Tech
Topic: Flat Plane V8 Race Engine - Single Exit Exhaust Question
Replies: 38
Views: 998

Re: Flat Plane V8 Race Engine - Single Exit Exhaust Question

Are pulse termination boxes not an option? Or is there sooner reason they would be undesirable and/or can't fit?
by BLSTIC
Wed Dec 04, 2019 10:08 pm
Forum: Engine Tech
Topic: Free - hi-tech 5-75 hp dyno
Replies: 17
Views: 948

Re: Free - hi-tech 5-75 hp dyno

You wouldn't have some kind of CVT between the engine and flywheel would you? It wouldn't work continuously, but you could get a few seconds of steady state in. Or as has been mentioned, a retarder of some kind on the flywheel Is there torque measurement on the shaft between the flywheel and engine?...
by BLSTIC
Tue Dec 03, 2019 3:14 pm
Forum: Engine Tech
Topic: Plenum box with two inlets and one outlet
Replies: 8
Views: 1651

Re: Plenum box with two inlets and one outlet

I was going to say that a blow through maf sounds like a lot of trouble. But so does blending two maf signals, I don't know of many ECU's thay could handle that and I'd doubt the accuracy of using only one maf in a twin system. The Z32 was twin everything except airflow meter
by BLSTIC
Mon Dec 02, 2019 7:08 pm
Forum: Engine Tech
Topic: How to fight exhaust reversion when the primaries are way too short
Replies: 142
Views: 9916

Re: How to fight exhaust reversion when the primaries are way too short

It looks like it works because the sharp change in area and having an exhaust plenum means that the blowdown pulse from one cylinder going up the other pipes is reduced by a *lot*. Also the short length of pipe means that any restrictions from running a smallish ID are minimised, so there's still so...
by BLSTIC
Mon Dec 02, 2019 3:10 am
Forum: Engine Tech
Topic: How to fight exhaust reversion when the primaries are way too short
Replies: 142
Views: 9916

Re: How to fight exhaust reversion when the primaries are way too short

The ls7 style collector resembles both an anti reversion cone and a pulse terminator box. Isn't it effectively running "zoomies" with back pressure at this point? It looks like it works because the CSA change is so massive the pulses can't really interfere with other cylinders. Or did I get that wro...
by BLSTIC
Wed Nov 20, 2019 7:50 pm
Forum: Engine Tech
Topic: Interesting graph on plug orientation
Replies: 4
Views: 547

Interesting graph on plug orientation

Not asking anything, just sharing something I found So I was browsing for info on tumble and swirl and I came across this graph https://d3i71xaburhd42.cloudfront.net/4f478676fa4730111ebd96f5c1e6936753129610/2-Figure1-1.png The accompanying article can be found here https://www.semanticscholar.org/pa...
by BLSTIC
Sat Nov 16, 2019 6:33 pm
Forum: Engine Tech
Topic: Old 4v head, modifying for tumble and velocity vs flow
Replies: 7
Views: 541

Old 4v head, modifying for tumble and velocity vs flow

So I'm looking at my current car powered by a 4G94 with its head design from the early 90s (I believe the first SOHC 4 valve 4G9 head was in 91 and it wasn't updated before the GDI version appeared). From pictures (I haven't measured it or seen it first hand) it looks like a traditional dump port wi...
by BLSTIC
Fri Nov 15, 2019 8:43 pm
Forum: Engine Tech
Topic: Do electric turbo chargers work???
Replies: 22
Views: 1181

Re: Do electric turbo chargers work???

I mean clearly they do. But they require such a large amount of power that you can only use them intermittently at best. Kind of like a rechargeable nitrous system

If you had slightly too big of a turbo already installed it would make a good antilag setup.
by BLSTIC
Thu Nov 14, 2019 4:40 pm
Forum: Engine Tech
Topic: "Hedifolds" the good, bad, and ugly?
Replies: 13
Views: 662

Re: "Hedifolds" the good, bad, and ugly?

What's wrong with the flow implications? -Seems like it makes it very hard for people to screwup by choosing a low-velocity, over-sized header where it matters most (right after the exhaust port and for the first several inches); with a straight 6 like the B58 it also keeps the pulses separated pro...
by BLSTIC
Thu Nov 14, 2019 2:09 pm
Forum: Engine Tech
Topic: Mikuni carbs vs. injected ITBs
Replies: 29
Views: 727

Re: Mikuni carbs vs. injected ITBs

Would detailing the ITBs (knife edge, one sided narrowed throttle shaft e.t.c) close the airflow gap to flat-slide carbs? As an aside, how much power are you making? Modern injectors get some pretty fine droplets coming out and I think you'd struggle to best them with a carby. I don't think things l...
by BLSTIC
Thu Nov 14, 2019 1:55 pm
Forum: Engine Tech
Topic: "Hedifolds" the good, bad, and ugly?
Replies: 13
Views: 662

Re: "Hedifolds" the good, bad, and ugly?

They are fantastic for warmup emissions. Not having a huge external manifold saves an awful lot of heat dissipation area and the volume between the exhaust valve and the cat converter is smaller. The volume between exhaust valve and turbine is also much reduced, this would likely improve response. I...
by BLSTIC
Thu Nov 14, 2019 1:38 pm
Forum: Engine Tech
Topic: exhaust pipe extension beyond the collector
Replies: 5
Views: 351

Re: exhaust pipe extension beyond the collector

Assuming your engine doesn't actually want more collector length... A sharp step up to a much larger pipe (say 5" or larger pp) should keep your tuning the same and allow you to point the exhaust somewhere else. You can gradually neck it back down to 3.5 if you actually need to fit it through someth...
by BLSTIC
Tue Nov 12, 2019 5:41 pm
Forum: Engine Tech
Topic: Modern Engines & Static CR vs. Boost Levels?
Replies: 32
Views: 1065

Re: Modern Engines & Static CR vs. Boost Levels?

ptuomov - Would this high tumble port be of use to your Porsche build?
by BLSTIC
Tue Nov 12, 2019 6:27 am
Forum: Engine Tech
Topic: Modern Engines & Static CR vs. Boost Levels?
Replies: 32
Views: 1065

Re: Modern Engines & Static CR vs. Boost Levels?

Right. I'm gonna say Toyota knew about this for a while. I knew I'd seen that intake port somewhere before. This 4A-FE update was released in 1993. The 1998 1NZ engine has a similar intake port.

It's not *exactly* the super tumble port, but it's certainly comparable
by BLSTIC
Mon Nov 11, 2019 7:24 pm
Forum: Engine Tech
Topic: Modern Engines & Static CR vs. Boost Levels?
Replies: 32
Views: 1065

Re: Modern Engines & Static CR vs. Boost Levels?

I see what you mean with the diffuser angle. But wouldn't the inlet valve act as a kind of turning vane to make the mixture follow the roof anyway? It is still a flat plate at a 40°-ish angle to the port. That same screenshot you've shown shows a degree of mixture following the exhaust valve face on...