Guest QuasiMondo Posted July 3, 2003 Share Posted July 3, 2003 I'm in the initial planning stages of building up a 3.1 stroker engine when I came across some Weber throttle bodies that are a direct replacement for their 2-barrel DCOE carbs. Itlooks just like a weber carb except there are mounts for the injectors right after the throttle butterfly. The only thing I can't figure out is where the MAP sensor would go. Any experts on this? Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted July 3, 2003 Share Posted July 3, 2003 You will have to build a common vacum log to draw a signal from all tbs at once.... Quote Link to comment Share on other sites More sharing options...
Guest QuasiMondo Posted July 3, 2003 Share Posted July 3, 2003 How difficult will that be? Quote Link to comment Share on other sites More sharing options...
zcarnut Posted July 7, 2003 Share Posted July 7, 2003 You can use the aftermarket SDS controller and just use the TPS sensor to set the injector duty cycle without even needing a MAP sensor. Quote Link to comment Share on other sites More sharing options...
SleeperZ Posted July 7, 2003 Share Posted July 7, 2003 You can use the aftermarket SDS controller and just use the TPS sensor to set the injector duty cycle without even needing a MAP sensor. Huh? How are you going to get even close to a good fuel mixture without sensing load? What you are saying is, when you rev your motor up in the driveway, you are going to fuel it like WOT in third gear? No, you need a MAP sensor. Quote Link to comment Share on other sites More sharing options...
zcarnut Posted July 8, 2003 Share Posted July 8, 2003 Frankly, I was skeptical too at first, but check out their web site: http://www.sdsefi.com/techtps.htm After installing the TWM throttle bodies and using the SDS controller I was able to get a fellow club member's Z car to run great! (He just had to have the individual throttle bodies on his show car.) But this is not the set-up to use if you are concerned about gas mileage! Remember, MAP sensors _only_ work if you have sufficient plenum volume. This entails more than just making a simple "balance" tube to interconnect the intake runners. You need to construct something that _supplies_ the intake runners. Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 8, 2003 Share Posted July 8, 2003 Remember, MAP sensors _only_ work if you have sufficient plenum volume. This entails more than just making a simple "balance" tube to interconnect the intake runners. You need to construct something that _supplies_ the intake runners. The TPS can be used for load sensing in some situations, although I don't think it would work by itself on a turbocharged application. It is generally less accurate, though. One big advantage of the TPS signal is that it is not nearly as noisy as the MAP signal for high vacuum/low flow situations. This is why it is sometimes preferred for radically cammed engines and/or low volume IR manifolds. The TPS Blend function on the TECII and III basically performs a crossover function between the TPS at idle and the MAP for WOT, where it is more accurate. As far as plenum volume goes, for an IR manifold like we are talking about here, plenum volume won't matter at idle as it is on the wrong side of the throttle plates to help. If you want to use a MAP sensor, summing all of the runners together is essential - it maximizes the volume that the sensor is drawing from, and smoothes out the individual pulses from each cylinder. At higher rpm/load, this becomes less and less of a problem. Using the TPS here can work, assuming it's a NA application. Personally, I would prefer to use the MAP signal, possibly blended with TPS if you have that functionality. I would only go TPS-only as a last resort. Quote Link to comment Share on other sites More sharing options...
Guest z1 performance Posted July 9, 2003 Share Posted July 9, 2003 let me know if you need the Webers! Quote Link to comment Share on other sites More sharing options...
zcarnut Posted July 9, 2003 Share Posted July 9, 2003 I completely agree that using a MAP sensor is the preferred or the “engineering correct” method, but it is not the only method. I have worked on or inspected several Z cars with the individual throttle bodies and _none_ of them used a MAP sensor. I was only offering QuasiMondo a viable alternative solution. I am fully aware of the pulsating nature of the airflow in intake runners and the improvement a manifold makes to the vacuum signal. But maybe he does not want to hack up his throttle bodies? Which, if not done correctly will look like a kludge job and will reduce any re-sale value of his throttle bodies. From what I have seen, most of the people who install the individual throttle bodies are more concerned with the “eye candy” appearance of the throttle bodies than with their driveability or practicality. For example, I’ve never seen anyone even using air filters with them. Quote Link to comment Share on other sites More sharing options...
Guest QuasiMondo Posted July 9, 2003 Share Posted July 9, 2003 I was going to ask about whether or not the TPS can be used instead of a MAP sensor, but I do suppose it depends on how I plan to use the car, and my plans, etc. Like I said, I'm still in the planning stages of this all. I'm not planning on going the turbo route when I build this engine. It's going to be used as a weekend cruiser, not a daily driver, so mileage concerns aren't that big for me. I wanted to use the throttle bodies because it closely resembles the look of having carbs. I know I can just save myself a lot of trouble and use carbs instead, but I'm from the Pepsi generation, and using carburetors is as foreign to me as vinyl records and 8-track machines. I'm going to keep researching this, and if you have any more tips , feel free to let me know. Z1, as soon as I land my hands on a Z to work with, I'll be sure to ask about those throttle bodies Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 10, 2003 Share Posted July 10, 2003 I am fully aware of the pulsating nature of the airflow in intake runners and the improvement a manifold makes to the vacuum signal. But maybe he does not want to hack up his throttle bodies? Which' date=' if not done correctly will look like a kludge job and will reduce any re-sale value of his throttle bodies. [/quote'] You wouldn't need to hack up anything. most of the IR manifolds that I have seen have female pipe fittings in each runner, and the TBs generally have vacuum hose barbs for each throat. All you would need to do would be to run a vacuum line from each runner (or throat) to a seperate summing canister and take your MAP reference from there. Quote Link to comment Share on other sites More sharing options...
Guest 81na ZX Posted July 11, 2003 Share Posted July 11, 2003 TWM makes TPS that bolt to the end of the, uh, throttle rod - the one the butterflys bolt to. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted July 11, 2003 Share Posted July 11, 2003 TWM makes TPS that bolt to the end of the, uh, throttle rod - the one the butterflys bolt to. uh.... I think we are talking MAP sensor here, not TPS.... Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 11, 2003 Share Posted July 11, 2003 TWM makes TPS that bolt to the end of the' date=' uh, throttle rod - the one the butterflys bolt to.[/quote'] uh.... I think we are talking MAP sensor here, not TPS.... No, he's right - there is a version of the TWM DCOE replacement that has a mounting boss for the TPS sensor, and it mounts on the throttle shaft. Quote Link to comment Share on other sites More sharing options...
RB26powered74zcar Posted July 11, 2003 Share Posted July 11, 2003 I'm in the initial planning stages of building up a 3.1 stroker engine when I came across some Weber throttle bodies that are a direct replacement for their 2-barrel DCOE carbs. Itlooks just like a weber carb except there are mounts for the injectors right after the throttle butterfly. The only thing I can't figure out is where the MAP sensor would go. Any experts on this? I could have swore we were talking about a MAP sensor... I do have the TPS boss on my foward TB, do you Tim ?? Quote Link to comment Share on other sites More sharing options...
TimZ Posted July 11, 2003 Share Posted July 11, 2003 I could have swore we were talking about a MAP sensor... I do have the TPS boss on my foward TB' date=' do you Tim ??[/quote'] Yes we were talking about MAP sensors, but TPS sensors worked their way in. My front TWM also has the TPS boss. Quote Link to comment Share on other sites More sharing options...
Guest JAMIE T Posted July 15, 2003 Share Posted July 15, 2003 I've been interested in using TB''s in place of webers for awhile, even posted a few questions on here, but never got many replies. Anyway, so to use these in a turbo application, I need to run vacuum lines from each runner to essentailly a vacuum can with a map fitting on it? OK, that does help clear some things up. Now, how much are the Weber TB's compared to the TWM's? Quote Link to comment Share on other sites More sharing options...
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