MAS airflow questions

[Killerbumblebee]

so in my quest to understand the almighty turbo, I have a question regarding engine managment or lack therof.

I know a few people have swapped modded 2.5L OBD2 engines into 1.8L OBD1 cars. They did this by simply switching the old sensors onto the new engine (as all of the plug ins are the same).

I also calculated the HP output of a stock legasy turbo to be roughly a 25% HP gain (the stock 2.2 puts out about 130, even with the lower compression of the turbo lock, I figure somewhere in the 120-125 range). The stock leggy SS puts out 160. calculated out, that's: 128%-133%.

so in my mind...calculated out, the same setup on a 1.8L engine would be: 141-146 HP

would you really need engine managment for this? couldn't the mass airflow sensor keep up with the extra power? couldn't the injectors keep up easily? please let me know what the problems would be. I expect it would run a little rich, but again, Im looking for imput from you guys. thanks!

 

[Jimbo]

I wonder if the ECU in the 1.8 has parameters to account for the increased demands for air/fuel? I mean, if what the 2.5 needs is "out of range" for the 1.8's ECU, then it might be a problem.

 

[Killerbumblebee]

no no, I the 2.5 runs. it runs ritch, but it runs without a lot of problems. it was done by eksjay (seth), with oversized pistons and some other stuff. on the 1.8 ecu he was running close to a 200 crank HP engine.

the car is now owned by the girl who bought my brighton, and she rally crosses it, it still runs just fine.

I'm mearly curious if the same logic can be applied to the stock turbo system out of a legasy turbo, in that the mass airflow will be able to handle a 25% HP gain by reading the amount of air the engine it taking and giving it the nessisary feul.

I would expect that if it can handle a 200 hp 2.5, a 140 HP 1.8 isn't a problem, the only thing I'm worried about is the injectors, although I belive they used the same injectors for the 1.8 and the 2.2, and the 2.2 makes 135 HP stock.

eventually, I do plan on using a greddy emanage system, with a bigger engine (probably a 2.5 STi block and 2.5 rs heads) on the same turbo with STI up pipe, and a performance downpipe. I'm making the car for autocross and rally cross/daily driving.

I also plan on using the rear end out of a leggy SS, which has LSD. the final drive on that is 3.9, which matches up perfectly to an STi tranny.

but in any case, what I was really wondering about was the mass airflow stuff.

 

[akinaspeedstar]

this seems like a really back wards way to boost this car. go on ebay find a EJ20g. you can have the whole thing engine trans axels fuel pump ecu ect for under 2700. and your done instead of frankenstiening an engine together piece by peice and hopeing that they all play nice together. the G is pretty much a ej22t but with slightly less displacement. it still has a closed deck silly intercooler and the works. just save your pennys and do that.

 

[Rightseat]

your proposed swap sounds like it places you firmly within the Unknown Zone Of Suby Swappage

hard tellin not knowin whass gonna happen. Goot Luck, you are gonna need it.

otherwise, go with the usdm wrx swap, wiring harness ecu and all. be patient, donor partz cars are out there.

personally I think if you ask an old N/A ecu to manage a turbo swap you are sking for plobrems like you never believed.

but don't let that dissuade you, experimentation is kinda fun in a weird way. long as you have a DD car that you can rely on, why not experiment?

 

[EvilAsPie]

It has been my understanding that n/a and turbo ECUs will not interchange no matter what car we are talking about. Timing is different in turbo cars. Air/Fuel multiplies faster then any n/a would be programed to do.

And don't turbo cars actual retard timing toward redline to eliminate "ping"? If that is the case a n/a ecu would pop a turbo engine pretty fast.

There are so many ways to get a turbo into any subaru as mentioned already. Added a turbo to an n/a just seams to be too much work, no bang for buck, work smarter not harder. Whatever Clich