Accufab throttle body and inlet support
- Thread starter Accufab
- Start date
PHXGT
GT Owner
Since the Accufab throttle body is the same size as the stock TB, what does it do different or how and why is it an improvement?
First of all, I think that the OEM TB does have a smaller diameter opening in the rear but that's not relevant anyway. CFM is not just based on the size of the hole. It's based on how much air can go through the hole. All throttle bodies have a resriction in them, namely the shaft and blade. Even in the fully open position, air has to flow around this obstruction so the design (and thickness) of the obstruction is very important, and in the case of the GT, the OEM TB allows for air seperation IN FRONT of the blades. In effect, all the air that would be possible to move through the stock openings is unable to do it. The sharp edges in front of the blades keep part of the inlets free of incoming air. Look closely at the leading edges of the Accufab TB in the photos and then look at the OEM TB and you will see what I'm talking about. We use an airflow bench at our shop to test for CFM on all of our new TB designs and compare these findings against the OEM TB's on the same flow bench.
Dr. Sims:
Was there a reason why you did not install the Accufab modifications yourself? Was this a time restriction or did you feel that a self-install was not realistic?
Now that they are complete (as of today), what subjective differences do you experience?
(I cannot recall which exhaust you have)
- doc
Was there a reason why you did not install the Accufab modifications yourself? Was this a time restriction or did you feel that a self-install was not realistic?
Now that they are complete (as of today), what subjective differences do you experience?
(I cannot recall which exhaust you have)
- doc
sharp33
GT Owner
Accufab said:
The design makes sense and it looks great too. Do you know if this modification affects the new car warranty and is this mostly installed by dealers or your average "do-it-yourselfer"?
throttle body
I feel I could have done the install of the throttle body & inlet stiffner myself but there is a minor recalibration of something related to the throttle body that my dealer recommended. Since my GT is at the dealership for the body shield, Ida exhaust & Ford trans cooler I thought I'd let them do it. One interesting fact is that Accufab doesn't offer dealers/merchants a dealer price. It's retail pricing for everyone so my dealer was nice enough to sell it for me for what he paid, which is what I would've paid had I ordered it myself. Luckily, this isn't the case for Ida & almost all other manufacturers/distributors.
I don't expect huge gains from the exhaust & throttle body; but any time it is easier for air to go in & out, the engine does less work. Also both were chosen for their "cool" factor. People already love to see the engine but now it'll be even more sano!
The exhaust & cooler will allow the trans & engine to operate cooler. I'll let everyone know how it is this weekend.
Ed
I feel I could have done the install of the throttle body & inlet stiffner myself but there is a minor recalibration of something related to the throttle body that my dealer recommended. Since my GT is at the dealership for the body shield, Ida exhaust & Ford trans cooler I thought I'd let them do it. One interesting fact is that Accufab doesn't offer dealers/merchants a dealer price. It's retail pricing for everyone so my dealer was nice enough to sell it for me for what he paid, which is what I would've paid had I ordered it myself. Luckily, this isn't the case for Ida & almost all other manufacturers/distributors.
I don't expect huge gains from the exhaust & throttle body; but any time it is easier for air to go in & out, the engine does less work. Also both were chosen for their "cool" factor. People already love to see the engine but now it'll be even more sano!
The exhaust & cooler will allow the trans & engine to operate cooler. I'll let everyone know how it is this weekend.
Ed
Black2003Cobra
Well-known member
Ditto. I would like to know this, too. Can you post the number please along with the test conditions? Oh, and what is on the back of the TB when you do the test, or is it just the bare TB? Thanks!lthlvpr said:
PHXGT
GT Owner
John Mihovetz is going to get the CFM numbers for me, they are in his notes. As far as the tests, we have a SuperFlow Flow Bench and test the TB's just like they test carburetors. The CFM is at various inches of water and if I recall, we publish the flow ratings at 28" of water. These are all listed as "naturally aspirated" flow ratings and are used more for comparison purposes than actual numbers given that some applications are using a "blow through" type of supercharger or turbocharger and some (like the GT, Cobra and Lightning pick-up) have a "suck through" type of suppercharger.
As promised, here are the flow ratings and comparisons. The stock GT throttle body is good for 1590 CFM and the Accufab TB is good for 1807 CFM, both at 28". This is just under a 14% advantage in CFM (cubic feet per minute) rating. It must be noted that these CFM numbers are in a naturally aspirated environment. In actuallity, the CFM is considerably higher (for both TB's) because the supercharger is "pulling" or sucking the air through the TB's. How well air moves through the TB, from the front or leading edge of the TB to the back, is a critical factor. We have taken alot of time and effort to insure that the transition of the air, from the hose in front of the leading edge of the TB to the blades themselves, and then over and under the blades, is as smooth as possible, to prevent large scale air seperation, something that is prevelent with the stock TB.
Black2003Cobra
Well-known member
So was this just the TB alone, or was the test done with the plenum on the back of it? If not, do you know any flow info about the plenum? Thanks for supplying the data! :cheers
throttle body installed & removed
My dealer installed the throttle body but the idle would not return to it's proper RPM without blipping the throttle or tapping the throttle body. It has been sent back to Accufab to be examined &, hopefully, repaired. The inlet stiffner is in though.
I had previously posted that my dealer had to pay retail for the throttle body. It's because a reseller has to become an Accufab dealer (minimum regular puchase) to be able to buy their products at below retail cost. My suggestion; therefore, is to buy their products yourself. Unless you know of an Accufab dealer in your area. Accufab also charged my dealer sales tax & then my dealer had to charge me sales tax. I believe my dealer went through some hoops to be able to have the sales tax, he had to pay, refunded. He's not happy.
I'll let you know how the throttle body works when it is returned. It sure looks cool!
Ed
My dealer installed the throttle body but the idle would not return to it's proper RPM without blipping the throttle or tapping the throttle body. It has been sent back to Accufab to be examined &, hopefully, repaired. The inlet stiffner is in though.
I had previously posted that my dealer had to pay retail for the throttle body. It's because a reseller has to become an Accufab dealer (minimum regular puchase) to be able to buy their products at below retail cost. My suggestion; therefore, is to buy their products yourself. Unless you know of an Accufab dealer in your area. Accufab also charged my dealer sales tax & then my dealer had to charge me sales tax. I believe my dealer went through some hoops to be able to have the sales tax, he had to pay, refunded. He's not happy.
I'll let you know how the throttle body works when it is returned. It sure looks cool!
Ed
Flow numbers with the "plenum"? What plenum, there is no plenum? The TB bolts directly to the supercharger inlet.
As far as sales tax, your purcheser is in California, as are we. Therefore, sales tax is required unless the purchaser provides a copy of his Resellers Permit, which he didn't do. As far as not returning to idle, this is because the installer probably didn't check and/or adjust the TPS voltage.
This issue about "I'm a Ford dealers and therfore I should be able to purchase a throttle body at wholesale" comes up periodically. Like many companies, Accufab Dealers are required to have an initial "buy in", meaning that unless they spend a minimum of $3000 on their intitial purchase, they are treated like all customers and pay what is known as "racer net" which is retail. Sometimes they get a little uppity at that but when I purchase a new Ford and tell them that "I'm with Accufab and I should get the car wholsale", they kind of look at me with a blank expression, LOL.
As far as sales tax, your purcheser is in California, as are we. Therefore, sales tax is required unless the purchaser provides a copy of his Resellers Permit, which he didn't do. As far as not returning to idle, this is because the installer probably didn't check and/or adjust the TPS voltage.
This issue about "I'm a Ford dealers and therfore I should be able to purchase a throttle body at wholesale" comes up periodically. Like many companies, Accufab Dealers are required to have an initial "buy in", meaning that unless they spend a minimum of $3000 on their intitial purchase, they are treated like all customers and pay what is known as "racer net" which is retail. Sometimes they get a little uppity at that but when I purchase a new Ford and tell them that "I'm with Accufab and I should get the car wholsale", they kind of look at me with a blank expression, LOL.
Black2003Cobra
Well-known member
Gotcha...straight in! (I mistakenly thought it was similar to mine, which has a plenum between the TB and SC inlet.) Thanks again Jim.Accufab said:
AMB
GT Owner
Ed Sims
You must have got a EARLY Accufab TB, like me !! The PROBLEM is a "WEAK" TB spring. Accufab has a UPDATED TB spring. You ALSO need to CHECK your TPS voltage of the STOCK TB before you remove it, and SET the Accufab TB TPS voltage to the SAME or a LITTLE less than with the STOCK TB TPS voltage !! IF you can't get the TPS voltage AT or a LITTLE less than the STOCK TB, you will have to drill out the two TPS screw holes untill you can get the voltage CORRECT !!!
AMB
You must have got a EARLY Accufab TB, like me !! The PROBLEM is a "WEAK" TB spring. Accufab has a UPDATED TB spring. You ALSO need to CHECK your TPS voltage of the STOCK TB before you remove it, and SET the Accufab TB TPS voltage to the SAME or a LITTLE less than with the STOCK TB TPS voltage !! IF you can't get the TPS voltage AT or a LITTLE less than the STOCK TB, you will have to drill out the two TPS screw holes untill you can get the voltage CORRECT !!!
AMB
I find it hard to believe that an installer would swap out the TB without noting the TPS voltage of the stock one and using this as a reference point on the Accufab unit. This is installation 101. With a TBs wap , first you should match the stock TB voltage and check the idle. It may take some time for the PCM to adjust for the airflow difference. Drive it around a few minutes after idling for a bit. If the idle seems erratic or too high, you may need to slightly adjust the voltage downward. Otherwise, I normally recommend disconnecting the battery or PCM for a few minutes and then reconnecting so it can learn from scratch.
I haven't heard about the spring issue, but this could certainly cause some problems if the supercharger was sucking the blade open slightly from too little spring constant.
Hope this helps!!
I haven't heard about the spring issue, but this could certainly cause some problems if the supercharger was sucking the blade open slightly from too little spring constant.
Hope this helps!!
TPS voltage, etc
The TPS voltage was checked & adjusted. It may be a mechanical issue as a tap of the throttle body or a tap of the gas pedal returns the idle to normal. Accufab told us it may be a bur or rough spot in the throttle body & to return the unit for inspection.
I'm not sure why Accufab posted what they did in relation to my dealer, Harrold Ford in Sacramento, as they have been on the phone to each other quite a bit. They know he checked & adjusted the voltage. They also know my dealer gave them his CA resale number but they insisted on completion of a long verbal form on the phone. To state the dealer wouldn't give them his resale number is not true.
I'm not trying to flame on anyone. I love the Accufab product line. I can't wait to get the TB installed & working properly. This is probably a result of miscommunication. It will all work out.
Ed
The TPS voltage was checked & adjusted. It may be a mechanical issue as a tap of the throttle body or a tap of the gas pedal returns the idle to normal. Accufab told us it may be a bur or rough spot in the throttle body & to return the unit for inspection.
I'm not sure why Accufab posted what they did in relation to my dealer, Harrold Ford in Sacramento, as they have been on the phone to each other quite a bit. They know he checked & adjusted the voltage. They also know my dealer gave them his CA resale number but they insisted on completion of a long verbal form on the phone. To state the dealer wouldn't give them his resale number is not true.
I'm not trying to flame on anyone. I love the Accufab product line. I can't wait to get the TB installed & working properly. This is probably a result of miscommunication. It will all work out.
Ed