Dat sound - ITBs

[RickyB]

Originally Posted by diss7

I agree I dont think the MAF placement is ideal.

A well setup ITB setup is fine for daily driving. My ae86 had itb's before it become full race car, and I drove that every day.

You are correct, the problem is that most folks buy into a bad setup and then end up very unhappy when they get to the tuner and find out that the car cannot be tuned to behave like a nice daily driver. I've tuned many OEM and properly setup ITBs and all gave excellent results and drivability. I've also had a number of customers bring in engines with oversized ITBs that looked very cool, but could not be properly tuned. In several cases, I put in a pedal stop that allowed only about 1/3 of normal pedal travel and showed the customer that on the dyno the car would make the same peak amount of power with and without the stop. The problem with such setups is that the slightest change in the position of the pedal would cause such an instant difference in torque output that no amount of throttle enrichment would prevent the engine from bogging on transitions. In the end, only the customers that took my advice and properly sized their ITBs got any satisfaction at about 2x the cost they had originally expected.

I guess what I am trying to say is that ITBs are cool, but if you want to convert to ITBs, make sure you go with a shop that really has experience building and tuning ITB setups. Don't let anyone talk you into supersizing the throttles because in the end it is not the throttles that ingest air, it is the engine and the engine will not ingest any more than the cams and its displacement allow it to.

[cyde01]

Originally Posted by diss7

I agree I dont think the MAF placement is ideal.

A well setup ITB setup is fine for daily driving. My ae86 had itb's before it become full race car, and I drove that every day.

i apologize for sounding like a noob.. so you don't have to re-tune the ecu for weather/temp/altitude changes? i've never had a car with itbs before but i've heard they are very difficult/finicky to get the tune right.

[diss7]

Originally Posted by cyde01

i apologize for sounding like a noob.. so you don't have to re-tune the ecu for weather/temp/altitude changes? i've never had a car with itbs before but i've heard they are very difficult/finicky to get the tune right.

No, at least I don't think so. They car had to run a stand alone (Link) and the tuner (nzefi) had tuned quite a few of the same setup (3sge with bored out blacktop 4age itbs).

Driveabilty wise, I didn't feel anything I would complain about. Starting on a cold morning was more difficult, but that was also not helped by having bumped up the compression, and using a small cca battery. Quick squirt of starter fluid into the trumpets would get it started if the battery couldn't.

[cyde01]

i used to own an S2000 and in that community there were very few stand alone ecus available for running itbs. i don't think any of them could sense and automatically adjust for altitude or temperature changes. i do know there were "learning" standalone ecus that could sense and adjust that were available for the 4a-ge. with dbw, d-4s, it seems like there would be a lot of hurdles towards getting a reliable, daily drivable itb setup on the fa20. this is just an assumption but an all new standalone would have to be made in order to do this, right?

[geezer86]

Couldn't you use ITBs to control airflow and retain the existing FI system?
Center facing side draft side configuration with decent length runners.
Pull vac from each runner for combined manifold pressure .
Box the trumpets and use original MFS. even the original air filter.
The original throttle actuator could operate the linkage.
Nissan used "dry" ITBs with port injectors with good result.
It seems well tuned intake runners and ITBs could net good throttle response and help torque
without changing out the whole system.