MAFT tuning and timing

[Clipse]

What's the down side of reduced base timing? In other words, how much would you recommend reducing it in a effort to control knock and what's the trade off, if any.
I've read that virtually no 92 model ECUs were EPROM. I haven't opened mine but am reasonably sure that it is not. I wouldn't mind having a chip - I just have to find/buy the appropriate ECU and have it socketed. I was working on more basic mods first and didn't anticipate a need for another ECU yet. I appreciate your description of the syndrome. I only wish I had read about it somewhere prior to buying injectors - I would have bought 550s in an attempt to minimize the problem. This might be a dumb question but I'm not a MAFT expert so bear with me: Since I didn't have problems with the MAFT set for 450s the airflow the MAFT was reporting to the ECU worked O.K. for my setup and normal base timing. If I set the MAFT to as small an injector size as the ECU can adjust the mid fuel trim for, am I helping my situation any?

I reduced my base timing to 0btdc and there has been no downside at all. If you have an AFPR, try tuning with that so the ecu isn't seeing so much correction and adding timing hence causing knock. I've got mine down to a max count of 9 in second and 4 in 3rd. Still working the bugs out, but things are looking up.

 

[WTNGST]

I reduced my base timing to 0btdc and there has been no downside at all. If you have an AFPR, try tuning with that so the ecu isn't seeing so much correction and adding timing hence causing knock. I've got mine down to a max count of 9 in second and 4 in 3rd. Still working the bugs out, but things are looking up.

I think you lost me there on the AFPR comment.

 

[Clipse]

I think you lost me there on the AFPR comment.

Adjustable fuel pressure regulator

 

[98spydert]

It's not the MAFT, its 'piggyback syndrome'. Sometimes these are worse with the MAFT over an SAFC due to the much easier spooling and increased part throttle power.

There are 2 things that happen when you make a big injector shift with a piggyback. 1 is increased timing because the ECU believes there is less air flowing. The other is delayed WOT or Open Loop mode. Sometimes this is called part throttle lean-out. It's fairly common.

The timing can be handled somewhat by reducing the base timing setting.

The delayed WOT mode is something that can be corrected externally, we are working on that.

Another solution is to run an chip in the ECU set up for those injectors. It handles both problems and has other benefits as well. Then you have the good spool benefit of the MAFT and extra's from the upgraded chip.

Bob

Bob, what's with the low throttle knock that comes out of no where? Have you guys experienced it over there at FTS and have you looked into it at all. After reading here, FTS tech forums, and DSMtalk, there seems to be a lot of people with the same problem. A lot of us have switched back to the stock MAF just to be sure and it all goes away until the MAFT is reinstalled. Any news?

 

[WTNGST]

Adjustable fuel pressure regulator

Yeah, I got that. I just never thought of an AFPR as a tuning tool.
Always learning new things. I'm glad these forums are around.
I'm looking at buying the Buschur bolt on now. I waited almost a month for the full throttle one and gave up.

 

[kpt4321]

Bob, what's with the low throttle knock that comes out of no where? Have you guys experienced it over there at FTS and have you looked into it at all. After reading here, FTS tech forums, and DSMtalk, there seems to be a lot of people with the same problem. A lot of us have switched back to the stock MAF just to be sure and it all goes away until the MAFT is reinstalled. Any news?

Huh? In the quote that you replied to, Bob supplied information and suggestions. What are you asking?

 

[slickster]

Hey Spydert,
I have your identical setup.....knock is all over the place. I can rev to like 3K in neutral and knock runs wild. Let me know what you find out and vice versa.
Slickster

 

[98spydert]

Huh? In the quote that you replied to, Bob supplied information and suggestions. What are you asking?

Read carefully and you'll see what I'm asking. I recongnized the screen name from the FTS tech forum and wondered if, while combating other MAFT problems, they have looked into the knock problem lots of people are having. Thanks for the useful post though.

 

[sophat34]

if I may ask what is the fts forum? I have the same problem, knock at part throttle goes threw the roof. I am guessing that its phantom knock? I just changed the settings on the dsm link to ignor it, not sure if that was the right thing to do or not. it didnt seem to hurt any thing and the wideband still reads slightly rich.

 

[98spydert]

FTS is Full Throttle Speed. They're aparently the people responisble for making the MAFT. Their "tech support" forums are here: http://www.fullthrottletech.com/forums/index.php No one really answers about 2Gs and our misterious knock problem though, it seems anyone there with a decent amount of knowlege and experience owns a 1G.

My new plans are to rewire all of the major ground connections and the major power wires with 8 gauge wire. I've heard it can make a difference and it will most likly help other things even if it does nothing for my phanton knock. I'm gonna keep doing boost/vac leak tests also. I'm keep everyone posted if I find anything new regarding the knock situation.

 

[44pirate]

FTS is Full Throttle Speed. They're aparently the people responisble for making the MAFT. Their "tech support" forums are here: http://www.fullthrottletech.com/forums/index.php No one really answers about 2Gs and our misterious knock problem though, it seems anyone there with a decent amount of knowlege and experience owns a 1G.

My new plans are to rewire all of the major ground connections and the major power wires with 8 gauge wire. I've heard it can make a difference and it will most likly help other things even if it does nothing for my phanton knock. I'm gonna keep doing boost/vac leak tests also. I'm keep everyone posted if I find anything new regarding the knock situation.

I put my grounding wires all back on. Idle is much smoother, but still have that tipin knock going on. WOT it is no problem.

 

[98spydert]

I put my grounding wires all back on. Idle is much smoother, but still have that tipin knock going on. WOT it is no problem.

Damn, any other new ideas on what to do about this tipin knock?