Yep, thinking it's time to bolt a turbo onto my 1.6l.



Here are my goals:



1. Find a turbo that would be reasonably acceptable between 4 and 10 PSI boost levels.

2. Do not go with an oversized turbo. My goal is no lag, not max power.

3. Find a turbo that is both available and inexpensive that meets those goals.



My plan is to initially run the turbo intercooled but without any additional engine management correction. I have a wideband, If I can only safely run 2 PSI without adjusting fueling, I'll only run 2 PSI at this stage. I am guessing I can push between 3 and 6 PSI during this stage safely. I would like to match a Beta's factory output, plus or minus. After I have this worked out I intend on wiring in an AEM FIC and turning up the boost to 8-12 PSI. My ultimate goal is 175bhp, I don't want any more than that. This is my autocross car + daily driver, not a drag car. I will either be making my turbo manifold from scratch myself, or if the turbo is compatible I might buy Fintile's turbo manifold if it's still available.



I have calculated out some requirements for my project, although I'm admittedly new to this and if it seems suspect feel free to double check my math.



I am assuming:



Intake temp: 130 degree F

Volumetric Efficiency: 0.92

A/F Ratio: 12:1

Max engine RPM: 6200

Displacement: 1.6l

Atmospheric pressure: 14.7 PSI

Compressor to engine loss: 2 PSI

Filter to compressor loss: 1 PSI



And I have broken it up into phase 1 and phase 2:



140hp level:

Pressure Ratio: 1.67

Actual airflow @ 6200RPM: 15.4 lb/min

Actual airflow @ 3000RPM: 7.3 lb/min

Boost: 6.2 PSI



175hp level:

Pressure Ratio: 2.05

Actual airflow @ 6200RPM: 19.3 lb/min

Actual airflow @ 3000RPM: 9.1 lb/min

Boost: 11.4 PSI



Ok, so now I have enough to plot on a compressor map. I have done so with a few turbos, some that seem like they would be decent choices include:



GT2052 727264-7 52.2mm 48 trim 0.51A/R



T3 45 trim (40 trim might work too)



TD04 13G



TD05 14G







Sorry, I didn't print them out and scan them back in, you'll just have to make do.



Now, aside from these compressor maps, I don't know much about any of these turbos. I don't know what the advantages of one vs. the other might be. I definitely don't want to spend a ton of money on one over another if there isn't any reason to. Any input is appreciated.

 

I wish I could be some help but I have no real knowledge other then the very basics on how it functions.

 

I wouldn't bet on being able to run ANY boost without some kind of fuel enrichment, I tried it (1.5 sohc) and the car leaned out-wouldn't even rev as soon as the turbo spooled up. I eventually got it to run by leaving the wastegate half open, I was getting some boost but the car wasn't any faster than stock. Just start with a 12:1 fmu, there like 60$ on ebay.

 

It seems to have been working pretty well for Fintile in the range I'm looking for, most of the time at least. There is a chance that he got leaner than I'm comfortable with though. If that happens I'll probably skip straight to a FIC instead of trying a rrfpr. Although that is certainly another option.

 

IMO a Super Sixty would be great. Would spool fast even at low boost pressure.



Um, a stock Sr20 turbo would be PERFECT!



there cheap and there reliable and there name brand.





Also there cheap to rebuild!



T25

 

If the issue is money then save up and DO IT RIGHT THE FIRST TIME. Otherwise you'll be buying a new engine as well. Have you looked into what Turbo Manifolds and downpipes are even available for the Alpha 1.6L? That may help determine what type of turbo you purchase.

 

What he said ^^^^



don't cheap out on the fueling and do everything right the first time, even for a low boost setup.



t3 60 would be a great fit for the accent mathematically speaking but would spool slightly slower than the t3 45. Knowing what a T3 60 is like on a tiburon, I would probably go with the smaller t3 45 on the accent if I was looking for the fastest spool. The t3 60 though, is at its greatest efficiency at both of those pressure/airflow levels though.



I wouldn't use an FMU. A RRFPR would be a decent idea for a budget minded setup as long as your not worried about extracting the most power out of it and you do have a Wideband (essential) since you can up the pressure a bit while retaining a good idle and it will reference boost.



I would still recommend the FIC though or something similar, even if its just street tuned.



Its really a toss up and comes down to if your wanting the fastest spool (like you mentioned) while not being concerned about the turbo being at its maximum efficiency or wanting a better power band with a bit more lag while keeping the turbo at its maximum efficiency.







the td04-13G would also be a good turbo to look at if your wanting to go mitsubishi. In my experience though, a t3 is more readily available.

 

Yeah im with TR on this one i would use a stock Sr20 or even a jetta 1.8t theyll reach your max of about 12hp without lag and very reliable. easy to rebuild and small in the engine bay

 

Looking at the compressor maps it seems like on both of those I would barely get to the point of max efficiency island of the turbo. Wouldn't I want to spread as much of my intended airflow range across the turbo's most efficient range possible, instead of only hitting max efficiency at max airflow? Or am I looking at this the wrong way?





There are effectively no turbo manifolds available for the 1.6L Alpha, at least at a price reasonable enough for me to consider buying. I'll either buy Fintile's used turbo manifold and it's set up for Mitsubishi turbos, or I would build my own log style. If I buy his I could either use an adapter, or weld on a different flange if I didn't want a turbo with that flange. There is no easy way to boost a 1.6l Alpha, I'll be doing most of this from scratch.



I have a history of doing things the hard way for research purposes and I have no problem with that. Like I said, I'll have a wideband and if it can't compensate I won't push it. Due to the experience of others there is evidence that it can compensate for a low amount of boost. I want to test this for myself, find the limits if it's true, and report back. If it's not going to work, I'll pull the turbo parts back off and wait until I have the rest of the stuff together. I'm only looking to add about as much additional power as I already have with bolt ons without tuning fuel, best case scenario.



So, is it better to have my max airflow at the turbo's most efficient, or to stay as efficient as possible over the entire range of airflow I want to utilize? Really, I want as much usable RPM range as possible. I will be in 2nd gear during the entire run on most autox courses, but that means I drop into the lower RPM's regularly. Ideally I would be making at least some boost at 1500 RPM's. Definitely by 2000 RPM's.

 

with that type of driving, i would probably lean towards the t3 45 then as it will spool up faster.



you will be less efficient at maximum airflow based on those calcs though but still will be a pretty efficient turbo choice. (outlet air will be warmer, yielding you less power) but you would still be around the 70% efficiency area which isn't bad.