Some observations with EGR

[vortecfiero]

Some observations with EGR

Testing was done as follows

Stabilize temps
Launch in 1st
Launch in 2nd
Cruse at 60mph hammer it in 5th (2300 rpm)
Back off, Cruise, down shift to 3rd and hammer it

2800 lb fiero 5sp
Engine nat. asperated 262 1st generation Internally balanced (my first engine)
160 deg thermostat
ported stock heads, stock valves
vortec exhaust manifolds (2 drivers sides) 2.5 exhaust, turbo style muffler
9.5 to one compression, forged pistons

crane cam 218/218 @ 050 454 lift
Sunoco 94

Test 1
no egr
Edlebrock dual plane
Edlebrock 500 cfm carb tuned for performance
HEI centrif. advance dist. set 8 deg initial, all in at 3000 36 deg
any more timing would ping like crazy

awsum off the line ok mid range screamed to 6000 rpm

Test 2

switch to TBI Injection (Stock) ECM controlled
no EGR
timing set at 0
pinged once and awhile

ok off the line, ok mid range died at 5000 rpm

Test 3

same as test 2 but with with egr, no ping and ok with 4 deg initial timing

nice off the line, great mid range, ok to 5000rpm

Test 4

back to edlebrock intake, fuel @18 PSI + adapter for TBI, ECM controlled (but fooled with)
drilled intake for EGR Passage and Ford style (sort of ) adapter (but with TBI) vacumm controlled,
liked 6 deg initial, 38 deg all in @ 2500

ok off the line, OHMYGAWD midrange, screamed to 6000 rpm

so, in each case it would seem cylinder head/combustion chamber temps would go down
with the EGR connected which allowed a little more timing

looking at the SyTy set up I would think that reducing the same temps in the head would
be almost as beneficial

any comments ?

 

[Sy769]

:rotestno:: EGR is bad.

Causes heat soak in upper intake.

Besides in syty's Egr is only enabled during cruise after the engine is warmed up. Why would you use it during a full throttle run. Fuel/air makes power not fuel/air/with exhaust gas.

 

[Ian Turgeon]

egr does 2 positive things:

decrease cylinder temp while operating.
decrease emissions.

but it does so at a cost of cool, burnable oxygen.

 

[vortecfiero]

i wonder if any one actually measured the cfm of the opening under the throttle body in the plenum for the EGR
(i figure its going to be 4.5 cfm based on a velocity of 450 ft /min) through a .375 hole
(ignoring the fact that exhaust psi can be as high as double intake pressure, and hopefully
not much more, so cfm of the egr gas could be less)
entering and mixing with 450 cfm of intake air @ 300 hp 70% efficient turbo
so about 1% say at 600 deg (whatever traveling through the intake egr passege reduces it to ?) mixing with
200 deg or so intake air at boost

can any body do the math ?

 

[smeagol]

I've just seen datalogs and had to clean out intakes, and heads.

The intake temps rise a LOT.

I've seen intakes with tons of grime in there.

Our trucks detonate way too easy, and any hot spots from carbon deposits or whatever, are just going to increase that tendency.

Any performance engine doesn't use EGR, that's all that matters to me. It's benefits are purely emissions & mileage (and the mileage is negligible in some respects).

 

[Sy769]

Any performance engine doesn't use EGR, that's all that matters to me. It's benefits are purely emissions & mileage (and the mileage is negligible in some respects).

Nothing like some Simple Green to clean the grease out of ones eyes :wink:

 

[Ian Turgeon]

same night same temp: seen egr on/off intake temps rise by as much as 20-30 degrees easy.

 

[vortecfiero]

I guess my point was cruising first (egr keeping heads cool when fuel is leanish (?) ) then nailing it.
I realize at wot the egr is not operating...