Slant Six Forum
https://slantsix.org/forum/

New Slant EFI intake....
https://slantsix.org/forum/viewtopic.php?t=53276		 Page 8 of 11
Author:  Sam Powell [ Sun Jul 27, 2014 11:41 am ]
Post subject: 
My Daughter's Civic, !-4 has a heat shield on the exhaust manifold that looks like it is about the right size for one of the Dutra Dual manifolds. They are bolted to studs that are in the exhaust manifolds themselves. If this is not the ideal adaptation, there are likely others out there in the yards that might be. Almost all modern engines have heat shields around the exhaust manifolds.

This is something one would have to mock up off the engine as clearance is very tight. I would be up for fabricating such shields when I have the engine down next time.

Does anybody here see any problem with drilling into the Dutra Dual casting to put a stud for mounting a heat shield?

Sam
Author:  sixinthehead [ Sun Jul 27, 2014 6:42 pm ]
Post subject:  re: injector heat management
This is stretching the memory more than a little, but I remember working on a late 80's-early 90's Frod 300 6 with a curved EFI intake that covered the injectors.
The factory arranged a little fender-mounted fan and plenum to cool the injectors.

I seem to recall some Bosch imports (or Nippondenso?) with a similar arrangement, but that's foggier still.

For what it's worth.
Author:  pishta [ Mon Jul 28, 2014 2:15 pm ]
Post subject: 
Lou, can you force the MS to go to cold start (choke on in carb land) with a bypass switch? Trick the MS into thinking the coolant temp sensor is showing below 130F, maybe with a 2 pole switch with a resistor on one side that emulates a cold CTS value ( or just open that circuit?) . Then when its running after about 30 seconds, throw the switch back to the bridged side to actual CTS reading. That would give you a longer pulse width to counteract the sluggish injector coil resistance. If ypu think its vapor lock, maybe a bypass to the return line controlled by a servo, hit it for 1-2 seconds prior to hot starting ignition and it will purge any vapor in the fuel rail back to tank.
Author:  oldskoolracer [ Mon Jul 28, 2014 4:41 pm ]
Post subject: 
My friend wired a variable resistor into his datsun in place of the CTS, allowed him to adjust fuel trim on the fly... Kind of a half-assed trick but it actually worked pretty good tricking the ECU into going richer or leaner at the turn of a knob...
Author:  pishta [ Mon Jul 28, 2014 4:52 pm ]
Post subject: 
Nothing half assed about that. Holley pro-jection had same enrichment pot adjustment but it was on the ecu, not remote. Of course your o2 feedback will go haywire for a few seconds....
Author:  Pierre [ Mon Jul 28, 2014 5:13 pm ]
Post subject: 
o2 feedback is disabled while in cold start enrichment iirc on MS. It will also kick in the IAC function too.
Author:  pishta [ Mon Jul 28, 2014 10:39 pm ]
Post subject: 
fooling MS CTS with a resistor, would that be enough to kick into cold start enrichment? There you go, sounds like a winner for a hot start issue!
Author:  Pierre [ Mon Jul 28, 2014 11:40 pm ]
Post subject: 
There are only 2 temp sensors in the megasquirt - air temp charge and coolant temp. Only coolant temp is used to determine cold start enrichment phase.

The thing is - it's not just a hot start, its a hot run issue. Fooling the ecu (by resistor or otherwise) isn't a cure-all your making it out to be pishta. Cold start accelerator enrichment also kicks in on top of o2 feedback stopping and iac.

MSII (and I presume 3) lets you use a second main fuel map under specified conditions. Unfortunately unless you have a temp sensor inside the injectors you can't tell if they are heatsoaked or not.

I wonder if using ev6 style injectors (the skinnier longer types) would make a difference - I haven't handled one before but by pictures their bodies are encased in plastic, whereas the ev1 types (shorter/stubbier) are mostly metal. The plastic otta reject more heat then metal? Same idea as the fuel line mod...

Edit:
Here's a pic for reference I found via some google-fu. Maybe their overall lengths are the same but you can see the ev6 type is covered in plastic head to toe. This may not be true of all ev6's.


Image
Author:  pishta [ Tue Jul 29, 2014 8:09 am ]
Post subject: 
I have Dodge Neon 2.4 EV6's on mine. Seemed to be a better fit for my design and they are plentiful at the boneyards. Much smaller plastic case, smaller coil, maybe less suceptible to heat soak? Itll be interesting to see if mine even function in their environment, AL bungs in the head, surrounded by coolant@190F. Mine may be less heat cycled as the coolant is a pretty stable insulator. How hot do you think the intakes are getting in your applications? Anyone with a laser thermometer?
Author:  Dart270 [ Tue Jul 29, 2014 11:09 am ]
Post subject: 
Silly me, I have not measured mine under different conditions. Will do that when I have the car out next.

Lou
Author:  Tim Keith [ Fri Aug 01, 2014 7:55 pm ]
Post subject: 
Quote:
Does anybody here see any problem with drilling into the Dutra Dual casting to put a stud for mounting a heat shield?

Sam
If there was a new intake manifold mounting a heat shield to the bottom of that might be a good idea.
Author:  the_engineers [ Fri Oct 24, 2014 10:53 am ]
Post subject: 
After looking at the log intake design, I have a couple of questions:

1) In Vizard's book, he talks about the length of the runner as being from the back of the intake valve to the backside of the throttle blade(s).

In your log design, wouldn't the runner length then vary by almost 18", the center-to-center distance between the intake ports on 1 and 6?

2) As we look at runner length, I think we need to account for the flow characteristics of the port design. In fluid-flow (air is a fluid), a 1.25" 90-degree elbow impacts flow to the same degree as 2.1 feet of straight pipe.
http://www.engineeringtoolbox.com/resis ... d_192.html

Given a 7" intake port in the head, a 7" runner from the head to the plenum and an 18" long log, in theory, your runner length on #6 would flow like a 57" long runner. This would impact resonance and might allow for a 47" (or whatever a particular combination needs to hit 1st wave) runner length.

Just my $0.02...
Author:  pishta [ Fri Oct 24, 2014 3:15 pm ]
Post subject: 
Not having read Vizards book, could he be talking about an I.R. intake? Sounds like it. What I have looked at seems to suggest the runner wave reflects back from the plenum enterance. Does it even propogate around a corner? I saw a nice DIY design of the popular Toyota 6 wedge intake. It was a 3-3.5-4" AL conduit 90 cut lengthwise, outside bend to make the outer edge and half radius. The inside bend at the front was the other half of the conduit cut, then he just made a flat base with IR stubs to ports and welded up the triangle top and bottom and formed the mouth up front for TB. TB was probably 6" from head.
Author:  emsvitil [ Fri Oct 24, 2014 3:49 pm ]
Post subject: 
When you have a plenum, the intake runner length is from the back of the intake valve to the opening in the plenum, not to the throttle blade.
Author:  pishta [ Fri Oct 24, 2014 5:11 pm ]
Post subject: 
As the throttle blade may be considered a 'plenum opening', I was thinking the runner end as the start point.[/img]
Page 8 of 11 All times are UTC-08:00
Powered by phpBB® Forum Software © phpBB Limited
https://www.phpbb.com/