Best Header with the Supercharger

[bomber]

Is a long or short tube header preferred with the Supercharger? Short tube is going to get you screaming at high end but what about at 1000-1500 RPM? The long tube header is going to pull like a beast coupled with the SC. I occasionally take the boat out but for all practical purposes, my Tundra is a fluff truck. No super heavy loads or off roading per say. So, I'm more interested in the low to mid range perfromance. Just thinking out loud, shouldn't the long tube headers and the SC keep you in an RPM range where there is no hesititation in acceleration during shifting? The short tube would still drop your engine RPMs (downshift) out of the headers performance range and amplify the hesitation.

Any comments from the experts would be appreciated.

Thanks,
bomber

[tundra4towin]

Great question…
Just thinking out loud here… Long tube headers enhance the effects of exhaust scavenging and the principle of exhaust scavenging is based on velocity. Velocity is affected by volume & flow rate. So I think the size of the tube would have a greater affect on where the header is most effective. A larger tube would require more volume (higher rpm) for the exhaust charge to reach the optimum velocity for scavenging. A smaller tube would reach that optimum velocity sooner in the rpm range but it might not be able to flow enough at the higher rpms.

Now add the SC to the equation and suddenly you have increased the volume at any given rpm range. So for discussion sake, headers that peak @ 2500rpm on a NA motor will peak at 2000rpm on a SC motor because the SC has forced more air - volume into the motor.

Just some food for thought…

[scdtrd]

Well..... from working with the S/C and dealing with this for a while, I can tell you that the headers will make MORE of a differance on a N/A engine than a S/C engine. The engine is basically an air pump. The more you open the intake and exhaust, the more efficent it becomes, thus more power. Also, like an air pump it can be "tuned" to make power in either the low, mid or upper RPM range. Now, add a S/C to the mix. Since the air is not having to find it's own way in, then you basically removed ALL the obsticals on the intake side, basically. Then, the exhaust should be opened up more for a S/C engine. More air combined with more fuel = MORE volume per power cycle. And additionally your not really worried (as much) about scavenging the cylinder as the air is being FORCED into the cylinder on the intake stroke, so it WILL be forced out during the small amount of valve overlap that occours. The temp. diff of the intake charge and the exhaust is so great as to set up a boundry between them. Like a cold front and warm front. Anyway.. it makes a diff, but not as much as you would think on a S/C engine. On a N/A it makes a lot of diff. as your "tuning" the resonance of the peak RPM power point. Bottom line, both benefit, one more than the other. I hope this helps.
SCDTRD

[bbarada]

I agree with the rationale. I have a Littlefield 671 blower on my boat and was told that the exhaust headers make little difference on a blown motor.

But, having said that, I installed the supercharger on my Tundra, then the JBA headers about 600 miles later. I could definitely feel an improvement with the headers. The improvement is mainly in the mid-range. The hesitation when shifting did not improve.

[bomber]

Thanks for all the great responses and sorry about the rambling on the first post. Straight to the point - will the S&S long tube headers eliminate the hesitation you see with the JBA, SS, short tube headers? Because torque and useable horsepower are created at a lower RPM for the long tube headers, when the Tundra shifts, the RPM lowers but not enough to take it out of the designed power band. If that is a true statement, can one improve the response of the SC by using long tube headers over short tube? I believe the answer is the SC sucks and blows through whatever pipes are there and scavenging is of less significance. That takes us back to header pipe diameter theory earlier. Less restriction or larger pipes seem to be the way to go and not so much the length? So the Autochrome short tube headers with a larger diameter, than what is currently available from anyone else, is probably the better header for use with the SC?

Great discussion, don't stop,
bomber

[scdtrd]

I agree with that statement. Diameter is paramount on a S/C engine. So.. the SS headers would be the "best" choice for the S/C people.. the long tube would be the best bet for the non S/C people...
SCDTRD

[bbarada]

Your logic makes perfect sense regarding the diameter and a blown engine. However, I don't think the improvement in the low end will fix the hesitation on shift. I believe that is caused by the ECU, as discussed in other threads here.

[scdtrd]

Originally Posted by bbarada

Your logic makes perfect sense regarding the diameter and a blown engine. However, I don't think the improvement in the low end will fix the hesitation on shift. I believe that is caused by the ECU, as discussed in other threads here.

You are 110% correct!! The shift stumble (what I call it) is the TRD Piggyback ECU making it's self known! TRD added to the mix a parameter that when the tranny is ready to shift, it reduces the pressure in the valve body for a sec, to reduce the "snap" of the extra power that is added because of the blower. In addition to this crap.. er um... purchased performance, the relay on the bypass actuator is opened and it lowers boost to further reduce power for the tranny to shift. All this adds up to a stumbly, bumbly, shift.. kinda like the truck dies for a second, then has to wake up and realize.. hey.. I am going forward!
It is embarrassing if you ask me. If you remove the lower hose to the boost actuator.. look at my pics and you will see.. then you have removed 1/2 of the offending additions. You will have to get the Unichip to remove the TRD ECU stumble. I then HIGHLY reccomend that you get the valve body modified to remove most if not all the slip. http://www.levelten.com/hydrosystem_import.htm
That should answer your questions on "what is a shift kit?"

That is the route I am going!
SCDTRD

[bomber]

Originally Posted by scdtrd

You are 110% correct!! The shift stumble (what I call it) is the TRD Piggyback ECU making it's self known! TRD added to the mix a parameter that when the tranny is ready to shift, it reduces the pressure in the valve body for a sec, to reduce the "snap" of the extra power that is added because of the blower. In addition to this crap.. er um... purchased performance, the relay on the bypass actuator is opened and it lowers boost to further reduce power for the tranny to shift. All this adds up to a stumbly, bumbly, shift.. kinda like the truck dies for a second, then has to wake up and realize.. hey.. I am going forward!
It is embarrassing if you ask me. If you remove the lower hose to the boost actuator.. look at my pics and you will see.. then you have removed 1/2 of the offending additions. You will have to get the Unichip to remove the TRD ECU stumble. I then HIGHLY reccomend that you get the valve body modified to remove most if not all the slip. http://www.levelten.com/hydrosystem_import.htm
That should answer your questions on "what is a shift kit?"

That is the route I am going!
SCDTRD

OK - so there is work after the SC install to get rid of that annoying shift hesitation. Interesting company that does the modification of the valve body to limit the slip. I can't imagine the Tundra Tranny being so weak that it's afraid of 350 hp. I believe in design margin but this appears excessive as to buffer the tranny from shifting forces. Anyway, you all answered a lot of questions except who has the best price on the SC? Anyone with an experienced Toy dealer in the Atlanta dealer that has performed an install? Man, I'd like to do this myself but have to consider the warranty

Thanks again,
bomber

[scdtrd]

Originally Posted by bomber

OK - so there is work after the SC install to get rid of that annoying shift hesitation. Interesting company that does the modification of the valve body to limit the slip. I can't imagine the Tundra Tranny being so weak that it's afraid of 350 hp. I believe in design margin but this appears excessive as to buffer the tranny from shifting forces. Anyway, you all answered a lot of questions except who has the best price on the SC? Anyone with an experienced Toy dealer in the Atlanta dealer that has performed an install? Man, I'd like to do this myself but have to consider the warranty

Thanks again,
bomber

Call Lagrange Toyota and ask for Mike Baker. He is a good friend of mine. Let him know that Scott with the Black Tundra.. Supercharged told you to call. Speak only to Mike Baker. He will hook you up on install. For pricing or parts, ask for JM in the Service dept. Tell him the same thing. They know me!
SCDTRD