Before I say anything, let me first say that even though I am a Visteon
employee (we're still Ford a bit longer) what I say in the following must
be taken as only MY personal opinion, as that is precisely what it is. If
you find this information interesting, I would incourage you to verify my
findings on your own, as any modifications you make to your car are at YOUR
own risk and not mine, Ford's, Visteon's, my family's, etc.
On to some OPINIONS from testing I have recently had done. At long last, I
have put on a flow bench a 1992 SHO air induction system. During the
testing I have formed MANY valuable OPINIONS for myself and I think you
will find them interesting to. My interest in this was from a posting from
a person on this list a few weeks (?) back. If I recall right, they pulled
their 'cone' from their induction system and swore torque dropped (a pretty
sensitive butt-dyno I might add). I found it interesting in the 10 years
these cars have been around that no one (published anyway) has flowed the
air induction system to determine what is going on, so that is precisely
what I did.
One more thought before I start onto the opinionated testing results. Many
think that torque and power are trade-offs in air induction system design.
That is true, in SOME cases where system lengths, diameters, volumes are
assisting/hurting intake manifold tuning at some RPM more than a base
design, however, air induction system restriction will always affect
volumetric efficiency at ALL rpms, so it is or particular interest.
As a rule of thumb, 3.3" H20 restriction on the flow stand is approximately
equivalent to 1% power loss. Secondly, I've assumed that the SHO engine
pulls ~ 300 scfm in lightly modified form @ 7000 rpm. If you've got more
than just a cat-back and a 80 mm MAFS, flow rates will be a little bit
higher.
On with the SHO air induction, these values were taken at 300-303 scfm:
1. Base '92 system (as sold in 1992) w/new 'generic' filter....10.0" H20.
2. Base '92 system w/'panel' K&N filter (new).................. 9.4" H20.
3. Base '92 system/w/gen. filter/no MAFS screen.................8.7" H20.
4. Base '92 system/w/gen. filter/no MAFS sceen/no 'cone'.......10.2" H20.
5. Base '92 system/w/gen. filter/no MAFS screen/no in fender....7.4" H20.
6. Custom system I, with Cobra K&N filter, stock MAFS/no MAFS
screen, and stock clean air tube, w/bellmouth in MAFS........5.7" H20.
7. Same as 6 but with no K&N filter & bellmouth on end of MAFS..5.4" H20.
8. Same as 7 but with no MAFS..just the clean air tube..........2.5" H20.
9. Custom system II, with Cobra K&N filter, Cobra filter adapter
plate, 80 mm MAFS ('93 Mark VII) style.......................3.4" H20.
10. Same as 9, but with new MAFS (bridgeless from '99 Excursion..2.6" H20.
11. Same as 10, but with standard Ford conical filter............3.1" H20.
12. Custom system, with 87 mm Pro-flow MAFS, and K&N, Cobra filter
adapter plate................................................2.6" H20.
OPINIONS I FORMED FROM THIS TESTING, in order of importance to ME:
1. The stock system is a 3% loss system, losing only 6-7 hp compared to
a bare throttle body. That is the limitation of the gain associated
with doing anything to the induction system. Proclamations of gains
up to this number and above should be regarded with the same caution
of a fruitcake this Christmas. As another opinion, this is a pretty
darn good base system.
2. Geez....the kid was right....pulling the cone WILL drop power! To
understand the significance, you should compare iteration 4 and 3.
Pulling the cone will drop power by up to 1.0 hp and may have other
affects on torque as previously noted. It makes more noise & thus maybe
SOUNDS better but does drop power as well as torque. Many of you out
there have made only this modification...not all is lost...spend
another 30 minutes and pull the whole box (expansion chamber) out of
the fender. You'll pick up an immediate 2 hp if you've already got the
cone pulled. If the cone isn't pulled you'll pick up ~ 1 hp.
3. K&N....hmm....I've seen mixed results with K&N filters and this is a
good case....the flow path through the stock box doesn't make full use
of the filter...MAFS sits over the media....so the K&N filter in a
stock box really doesn't help much...figure 0.5 hp max.
4. MAFS screen. OK, got to say it again. Pulling this out will affect
your T/F and will have the potential of screwing up a lot of stuff.
I wouldn't recommend to anyone to make this modification even though
it is more beneficial than a K&N filter in a stock box. 'Nuff said.
5. Custom system (#6). For a lowly $50, I put this system together and
run it on my car. Buy a Cobra K&N. Shove your current MAFS to airbox
rubber seal into it. Use a good helping of 'Seal All' or other
sealant
to make this an airtight seal, connect it to the MAFS, drill a hole in
the clean air tube & shove in the ACT sensor (seal it too). Buy a
bit of foam/rubber for the filter to rest on (to support/isolate it
from banging on the inner fender) and the flow results, show this
should have picked up almost 3 hp. Even this minor modification, will
also likely screw up the transfer function of the MAFS, but I have had
no problems. Again, do this at your OWN risk.
6. If you go with a custom system like #10, you should be able to pick up
nearly 5 hp on a stock SHO. How would I do this? Get a new MAFS from
somewhere like on the '99 trucks, send it to Pro-flow to have it
recalibrated (they quoted me $75 + shipping), get a new filter. Again,
I've not done this but may if I can keep my SHO around long enough.
Their address is 25760 John R. Road, Madison Heights, MI 48071.
Their e-mail is bestproducts
[email protected]. Make sure you talk
to them first as you'll have to send the MAFS/filter/all upstream
parts
to get this calibrated right. The benefit of this modification is no
LPM necessary. Depending on the cost of the MAFS, this entire
modification could cost under $300.
I'm glad to answer a few questions about this testing, but I can not test
more parts. Send questions off-line and I'll respond as possible. Please
remember that ALL above comments are my opinions and I making these
modifications to your SHO or other vehicle may cause you and your car harm,
damage, injury or death.
(Does that cover it????!? I hate legal crap but this is a crazy world.)
