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CSVT change at 3500 RPM

T

Tracedyahxy

CEG'er
Joined
Aug 31, 2009
Messages
103
Location
Somerset, WI
So I've had my car close to a month now (E0 CSVT with ~94k). I've been meaning to ask for a while, what happens at 3500 RPM's? It definitely gets louder and deeper, and pulls harder. These engines don't have any form of variable valve timing, correct? So then is it just a hot cam that happens to become really effective right then?

Thanks,
Brian
 
No, you have 12 runners on the UIM, 6 of them are secondary runners which feed into secondary ports in the lower intake manifold, when you reach 3,500RPM or so the butterfly valves in the secondary ports open, allowing more air into the engine.
 
IMRC. Intake Manifold Runner Control. An electronic device that tells mini plates in the LIM to open once it reaches a certain rpm. 3400 at WOT and 3900 just cruising around.
 
Harrry said:
IMRC. Intake Manifold Runner Control. An electronic device that tells mini plates in the LIM to open once it reaches a certain rpm. 3400 at WOT and 3900 just cruising around.
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The SVT is tuned differently than the regular duratec. IIRC The standard duratec starts to open at 3750, the SVT at 3250. That's at WOT of course
 
Harrry said:
Sorry man....but you are wrong about the WOT at 3250. Here is the catalog which is states 3400 rpm. My tuner showed me that parameters of the ECU IMRC. It showed 3400 on my svt at WOT.

http://www.rumodded.com/warmonger/2000Brochure_Page06.jpg
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Huh, guess so. My SVT owner supplement says 3250,it's also from 99(my car is a 2000), I'm lost. I'm not trying to argue, I think we have contradictory information. My car's performance and tone begins to change at 3250 rpms, do you think the timing and fuel increase would cause this? It doesn't really seem to make a lot of since to increase those parameters before the increase in airflow...I'm open to input on this.
 
tsSVT said:
Huh, guess so. My SVT owner supplement says 3250,it's also from 99(my car is a 2000), I'm lost. I'm not trying to argue, I think we have contradictory information. My car's performance and tone begins to change at 3250 rpms, do you think the timing and fuel increase would cause this? It doesn't really seem to make a lot of since to increase those parameters before the increase in airflow...I'm open to input on this.
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The short runners started to become a restriction at 3600 rpms (wot). So The runners had to be activating sooner.(or it would defeat the purpose) Fuel trims and spark had to change prior to the opening in preperation for the change of velocity...obvious the increase of air. In many dyno sheets you would see a change at 3200-3300 rpms before the secondaries open up.

That would be a direct indicator that the fuel trims at that desired rpm were increased. Which makes the opening of the butterflies so noticeable. In most tunning situations. People would end up with no noticeable change at 3400 rpms due to the proper fuel and spark manipulation. So the holy crap where did the power come from is from out true and loved svt groups ability to tune.

I just can't find my 1997 Original brochure...damnit :blackeye: I'll have to look for it, so i can give you an exact estimate of when those open on that car.
 
Harrry said:
The short runners started to become a restriction at 3600 rpms (wot). So The runners had to be activating sooner.(or it would defeat the purpose) Fuel trims and spark had to change prior to the opening in preperation for the change of velocity...obvious the increase of air.

That would be a direct indicator that the fuel trims at that desired rpm were increased. Which makes the opening of the butterflies so noticeable. In most tunning situations. People would end up with no noticeable change at 3400 rpms due to the proper fuel and spark manipulation. So the holy crap where did the power come from is from out true and loved svt groups ability to tune.

I just can't find my 1997 Original brochure...damnit :blackeye: I'll have to look for it, so i can give you an exact estimate of when those open on that car.
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On second thought that does make sense, a slightly rich condition and advanced spark to ease the transition and limit the possibility of detonation would be prudent.

:laugh: Yeah svt's tuning abilities never cease to amaze me. How else would you get 35 more horsepower with relatively minor engine modification.

My car is pretty early production for 2000(332), but I don't know why my car has the book from a 99, I wonder if they update the supplement at all. It lists the compression as 10:1 not 10.25:1 and has the wrong displacement too.
 
tsSVT said:
My car's performance and tone begins to change at 3250 rpms, do you think the timing and fuel increase would cause this?
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If you're going by the dashboard tach - that thing bogs like crazy. It's maybe accurate to within 500 RPMs, but don't trust it.
 
Andy Bennett said:
If you're going by the dashboard tach - that thing bogs like crazy. It's maybe accurate to within 500 RPMs, but don't trust it.
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Aint that the truth. Its crazy when you add a tach to the car and notice how much it actually jumps around which would probably drive a normal person crazy if the factory tach was that responsive.
 
tsSVT said:
My car is pretty early production for 2000(332), but I don't know why my car has the book from a 99, I wonder if they update the supplement at all. It lists the compression as 10:1 not 10.25:1 and has the wrong displacement too.
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Did you purchase it new? Whats the date of production on it? The 1999 had a bigger displacement. And the 2000 had a smaller displacement due to bore size.
 
Harrry said:
Did you purchase it new? Whats the date of production on it? The 1999 had a bigger displacement. And the 2000 had a smaller displacement due to bore size.
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No, I bought it in 03, DOB 11/16/99. Yeah I know the displacement changed, amongest other things. It's returnless, has updated iac,egr,dpfe,water pump, it has to be a 2000 motor. It is possible that the manuels may have been mixed up.

You all make a good point about the tach, it's a shame how inaccurate all of the factory gauges are.
 
tsSVT said:
No, I bought it in 03, DOB 11/16/99. Yeah I know the displacement changed, amongest other things. It's returnless, has updated iac,egr,dpfe,water pump, it has to be a 2000 motor. It is possible that the manuels may have been mixed up.
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Sounds like you got the wrong manual :crazy:

tsSVT said:
You all make a good point about the tach, it's a shame how inaccurate all of the factory gauges are.
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It is...but it's good that we can help share information on here to clean up any confusion that occurs :cool:
 
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