Does anyone know what larger throttle body matches and is plug and play? Or is there somewhere thay sells bored out throttle bodies?

 

Why do you want a larger throttle body if you don't mind me asking?

(I don't know the answer to your question)

 

If you can get a larger throttle body opening you can pull in more air. More air for manifold.

 

DANGER TO MANIFOLD!


Kidding but not kidding, Honed makes an adapter for larger K series throttle body but it requires tuning to run correctly.

 

Have you removed the restrictions in front of the throttle body?

You’re aware the larger bore TB you use the more sensative the low throttle becomes also right? Like say you went from and I’m just making this up, from a 60mm to 100mm TB, 5% throttle is a lot more air on the 100mm TB which is going to make the car more touchy at low throttle movements.

Not trying to discourage changing the throttle body just asking questions.

Does anyone know if there’s other L15 variants that use a larger TB than the L15A7?

 

I have only had the vehicle for a few months. I would like to make upgrades and create a fun unique budget build. I have not done anything besides installing a pioneer navi unit.

 

If you're just looking to tinker and mod for the sake of tinkering and modding, I'd look elsewhere first. Consider suspension and wheels/tires.
You could do an exhaust and a cold air intake which shouldn't require tuning or ECU programming. Someone can correct me if I'm wrong, but a larger throttle body (depending on the size) could very well mean A/F remapping.

 

Some engines and parts can have parts that are able to be swapped and the pig tail matches so it is plug and play with NO CODES. I was just asking if anyone figured that out yet.

 

Some engines and parts can have parts that are able to be swapped and the pig tail matches so it is plug and play with NO CODES. I was just asking if anyone figured that out yet...

 

My reply isn't about codes. It's about the change to your A/F (air/fuel) ratios. A larger throttle body means more air. If your ECU can't compensate for the additional air, then you'll be running lean. I'm not sure if the Fit can compensate or not, which is why programming/remapping might be required.

 

This. Your engine is already optimally tuned. Adding a larger TB will completely change how your motor responds to input. You also run a very high chance of running LEAN, which is the wrong end of Stoichiometric efficiency that you want to be on. In short, your motor will explode without a proper tune to accompany any hard parts changes.

 

The third generation (GK) fit has the L15B, which does make more power, probably due to having a DOHC instead of SOHC cylinder head, but one had to wonder if it used a larger throttle body as well.

the part numbers and look of the two are definitely different.


GE/2nd Generation

GK/3rd generation


Assuming the 2nd gen ECU can talk to and use the 3rd gen TB and that an adapter could be made, you still have to map/calibrate the throttle body’s 0-100% position. And then the fuel mapping probably would need some tweaking, the narrow band O2 sensor will assist the ECU with adjusting fuel trims, BUT. It would need to adjust them significantly I’d imagine which might throw a CEL (it might suspect something is wrong to need to add say 5-8% more fuel than expected) and isn’t a good way to adjust the actual fuel tables if you even had a way to do so, you’d want a wide band O2 sensor for that.

so this is what everyone is trying to explain, a change to the TB is significant far as the ECU is concerned, even if it didn’t allow that much more airflow because let’s say, the cylinder head with the oem cam can’t make use of the larger throttle body hardly.

This is where optimization comes in. Get rid of the restrictions in front of the TB, first, as well as in the exhaust, then look into a tuning solution. K tuner or stand alone. Then you can start to really mess with stuff.

these engines are known for being able to take a hell of a beating, not so much for making a lot of power… partly because there’s not much in the way of low cost tuning solutions, and how much do you really want to spend to get a 3-5hp improvement here and there?

 

Mostly due to direct injection which allows it to run a higher 11.5:1 compression ratio....the dohc probably allows a little more power due to valve timing. Throttle body is the same size between the GE and GK. You can make a decent amount more power with a larger throttle body but it's not just a bolt on affair, needs to be tuned professionally by someone who knows what they're doing.

 

Shame about the bit being the same, would have thought it might be a few mm larger. Oh well…

op there have been people that have built the L15A7 engine, just not a lot… custom cam, tuning etc. can bump it up some, most accept it for what it is. Especially since it’s not a port injected EFI fuel system and the $ to Hp ratio isn’t that great. It better to make the car lighter, or go full on turbocharged build or engine swap.

RJ, just asking since you knew about the TB without digging it up it seems, I don’t suppose theirs any chance the cylinder heads of the L series can be swapped around can they?

 

Throttle body changes do not usually cause air/fuel tuning issues. Possibly at throttle tip-in, as in if you suddenly stomp on the pedal, but considering it's a drive-by-wire system, throttle actuation speed may be too slow for that to matter. The ECM uses more precise methods to measure air flow (see "speed-density system" and "mass air flow system") which it then uses to calculate the proper fuel injection volume. That said, a significantly larger throttle may cause idle or cruise control stability issues.

Performance-wise, it won't do much. It will give you more of the engine's available power with less throttle opening. That may feel more responsive and powerful, but you'll find the top half or 2/3 of the throttle range is just the opposite - flat with no appreciable increase in torque or power as you push the pedal down. For a TB upgrade to make sense, you first have to upgrade the intake (air filter, MAF, resonator and associated ducting), cam profiles and possibly the intake manifold to a design that favors peak power over low-to-mid-range torque. Higher RPM operation may be needed to take advantage of that new air flow, which probably means rebuilding the block and head with aftermarket parts. A tunable ECM will be needed to make that new stuff play nice together and make good power, and plenty of dyno time with someone who knows how to tune it.

IMO, the stock Fit engines are pretty decent at what they do. If you want some fun engine noises, get an aftermarket intake (just make sure the MAF tube is exactly the same size as the original) but without all the resonator chambers (muffler boxes). If you want more power, look into a K swap - it will be much cheaper than building an L15. If you want a show car, maybe build the L15, but be aware that it won't be as good a daily-driver as the stock engine.

 

I'd really caution against screwing around with your intake unless there's a tune along with it.

Much greater return on investment with lighter wheels and a Progress RSB.

 

I think this should get more attention all around. Look at how many people track and autocross their Fits without changing or upgrading engine components. Wheel and suspension upgrades have a huge return-on-investment compared to engine mods.

If you want a fast car, or if you want a drag car, or if you want a race car, start with a different platform. You can get a Mustang or a 350Z for not much more cost than a Fit and start out with 150 more horsepower

 

I have no clue about the cylinder head, I have no interest in extracting more power out of the L15A7, I think it's perfect how it is but I autocross my Fit. Falken RT660+ 200 utqg tireson 11 pounds each Superspeed wheels, Riaction digressive coilovers, 10k front, 12k rear swift springs, Progress RSB, poly bushings front and rear, poly motor mounts, Honed strut tops and two camber bolts on each side giving me between -4 and -5 degrees of negative camber. I have finished 1st in my class in all 4 autocross events this year. The second gen is an absolutely fantastic platform with its super rigid unibody structure, money is better spent on high performance driver's training, learn how to trail brake, learn how to backside cones in a slalom, learn how to get the Fit to rotate in a turn, power mods on the L15A7 are a waste of money and the guy who says that a larger throttle body doesn't need to be tuned to actually make more power is 100% incorrect.

 

progress RSB? Seen the mentioned a few times but no idea what It is.

I 100% agree with you and I’m looking forward to also autocrossing my Fit, I was just attempting to address the OP’s question about wanting more power.

(I agree a engine swap is probably the best route, and for the cost and time unless you just really love the Fit, and some do, there’s lighter and better cars to start with for what you’d spend to swap it)

 

Progress RSB is the first upgrade to do on the Fit.