Skip to main content ↑ ↓
Topic: Stock speed density (Read 3252 times) previous topic - next topic

Stock speed density

what can you do to an engine but still keep it in the range of speed density? what do you need a chip of some sort to run 24+ 30+ injectors? and i checked 50tech.com no help there can someone help me connect the dots.....
TC50? Paul?

Re: Stock speed density

Reply #2 –
You can change anything you want, just have to be careful about the cam... You must maintain at least apoprox 16" of vacspooge if it's gonna idle decent and not be pig rich....


For instance the 5.0 Bird I just bought has Windsor jr heads, ported stock HO intake, cold air system, 65mm throttle body, 1.6 roller rockers, 2 1/2" exaust system, and a STOCK HO cam. It also has a Ford Racing Mass Air conversion kit with 19lb inj, but really doesn't need it because of the stock cam. For shiznitts I swapped it over to a '88 Mustang Speed densety HO EEC.. It still idles and drives fine and actually feels a little stronger. Which proves Mass Air is NOT needed for a stock cammed engine that has other performance mods...

Re: Stock speed density

Reply #3 –
would you happen to know the specs on a SO cam?

Re: Stock speed density

Reply #4 –
You want specs on an SO cam (E5AE-AA). Well here they are:
Lift Intake: .237
Lift Exhaust:.247
Duration Intake: 244 deg
Duration Exhaust: 256 deg
Event Phasing I open: 16 deg BTDC
Event Phasing I close: 48 deg ABDC
Event Phasing E open: 57 deg BBDC
Event Phasing E close: 19 deg ATDC
Overlap: 35 deg
Lobe center Intake: 104
Lobe center Exhaust: 111

For comparison 85 to mid 88 HO cam (E5ZE-AA) are:
Lift Intake: .278
Lift Exhaust:.278
Duration Intake: 266 deg
Duration Exhaust: 266 deg
Event Phasing I open: 17 deg BTDC
Event Phasing I close: 69 deg ABDC
Event Phasing E open: 67 deg BBDC
Event Phasing E close: 19 deg ATDC
Overlap: 36 deg
Lobe center Intake: 115
Lobe center Exhaust: 115

This from The Official Mustang 5.0 Technical Reference & Performance Handbook, Kirschenbaum, Bentley Publishers, covering '79 to '93 'stangs. If its useful to you ...enjoy, otherwise fuggeddaboudit! :canada:
87 Sport with HO cam, 19# injectors,TB+Upper Intake,87 Mustang EEC, Cloyes double roller timing chain, Kirban adj. fuel regulator and Autometer fuel pres. guage, HO shorty headers + LSC H-pipe and Dynomax Super Turbo lers, Ford Racing 9mm wires, K&N filter / no air resonator, 8.8 XR7 Diff., V rated tires, Project ongoing.

Re: Stock speed density

Reply #5 –
Multiply the lift figures by 1.6(or 1.7) to get the actual valve lift.

Re: Stock speed density

Reply #6 –
The way to keep a speed density computer happy and idling well is to keep the lobe separation angle on the cam higher than 112 degrees.  5.0 Speed Density LOVES 114 degrees and depending on the grind of the cam can tolerate 112 degrees.  These computers do not like the Ford motorsport cams (e-303, b-303, x-303, etc.) and as these were some of the first cams on the market for the 5.0 they started the myth that you can't run anything but a stock cam on speed density.  Funny how the GM buys been doin just that in F-bodies and vettes for about 12-13 years now.  Most GM people I know have actually told me that they do not like Mass Air systems.  Why? Because GM abandoned the setup on their performance oriented machines years ago and constantly developed their speed density systems to become better and better.  Chrysler has also done this.  Ford, on the other hand has done the exact opposite and shunned Speed Density while updating and improving their Mass Air systems.
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!

Re: Stock speed density

Reply #7 –
Gm abandond maf setups in 89 only to bring them back in 93.  Buick GN's were speed density though.
One 88

Re: Stock speed density

Reply #8 –
hey another side question.... what is the biggest injector you can run with a BBK FPR? and the computer can contain? 19? 24? 30? 42? lol

Re: Stock speed density

Reply #9 –
tom,
so in your professional opinion and years of tinkering,

Do you think that a maf conversion is less of a concern with you today.

Re: Stock speed density

Reply #10 –
A fuel pressure regulator can handle any size injector you can throw at it.  The limiting factors are your fuel rail, lines,fuel pump and of course your ECU.  As far as what size injectors a stock speed density ECU can handle,  are we talking SO or HO?
-- 05 Mustang GT-Whipplecharged !!
--87 5.0 Trick Flow Heads & Intake - Custom Cam - Many other goodies...3100Lbs...Low12's!
 

Re: Stock speed density

Reply #11 –
Quote from: jcassity
tom,
so in your professional opinion and years of tinkering,

Do you think that a maf conversion is less of a concern with you today.


Talking HO 5.0 here, if the engine is going to be making over 250-260HP then larger injectors and Mass Air are just about a must... Up to that point yo can use the SD and just tweek the fuel pressure a bit. All this more or less assumes the stock HO or other fairly mild cam is being used. If a long duration/narrow LCA cam is used that reduces vacspooge below about 16" at idle(my 5.0 idles about
11"-12" at 800 rpm), then mass air is mandatory.

As I already mentioned, my new toy seems to run a little better and quicker using SD. The real trial will be at the track when I can try it with both systems. Because of the Windsor Jr heads, 65mm Tbody,
 1 5/8" headers, 2 1/2" exaust system etc. it should run better on the Mass Air. But I can tell you this, a TOTALLY stock HO will be a little quicker on the SD. Been there, done that, got the Tee Shirt.