im new to this site, i recently bought an '08 honda fit with the HKS turbo kit on it already. im currently boosting 5lbs, but am considering buying new injectors and boosting 8 or 9lbs? is this a good idea with still having stock internals?

 

A scan gauge or an OBD2 pocket logger would be a good idea before making any adjustments.

I would be concerned with IATs, IDCs, Timing, Knock Retard, AFRs etc. that you current setup is producing before making any more power.

You might want to consider a UEGO gauge of some sort, an EGT would be a good idea as well. What sort of fuel you run will make a big difference. If you live somewhere that only has 91 octane for premium you should consider mixing some toluene or getting a progressive water/methanol kit to avoid pre-detonation.

How do you plan on tuning the larger injectors? AFC or a driver box?

HKS uses a GT2554R turbo in their kit right?

Reliability has less to do with overall boost and more to do with tuning and operating habits.

 

Plenty of Fit here pushing that mile after mile....BUT...it is all in the tune

 

I have the HKS turbo kit running with 5 lbs also. In the winter, sometimes it goes up to 6 lbs because the F-Con does the tuning. My friend told me that maybe we can use the RSX-S injectors. But for me, I would wait until the Hondata Flash Pro comes out and use that to tune. I have asked and it seems like 8lbs is still do-able and safe for the motor. As soon as you are at 9lbs +, you are @ red zone and might blow up the motor.Unless you polish the whole motor and change pistons; then it would be safer for daily drive.

 

sounds like i have a little bit to learn! is there a way to test my motor at home to see if it is healthy enough for more boost?

 

yeah ive heard the same about the RSX-S injectors. when is the hondata flash pro supposed to come out? would that eliminate the need to get a tune at a shop?

 

Well.. you're actually making more boost because the air is colder and denser not because of any function in the F-Con. Unless it comes with a wastegate solenoid.

It is not uncommon to see 1-2psi more on a 20*F day vs. a 70*F day.

Most turbo cars and many supercharged cars "overboost" past wastegate pressure when the air gets nice and cold. This can be potentially dangerous if you haven't properly supported that extra boost you might run lean and/or detonate from a spark scheme thats too agressive. Or just from the compression and high IATs.

This is why if you have tuned your car in the summer when it is hot/humid, and not left yourself a margin for safety and then go thrash it on a cold dry day you might go boom.

In an old car of mine with a stock fuel system and injectors, I melted a pizza slice shaped piece of an exhaust valve hat on a 5*F evening when I got on the throttle and instead of the 17-18psi I had tuned for at the time, it spiked to at least 20psi, I say "at least" because the gauge I had at the time only went to 20psi and I did not have a MAP sensor at that point... 112% IDCs

This was because I had a pathetic 100lph (@12v) stock pump on old crappy stock wiring feeding small factory fuel lines, filter and even a couple of super restrictive banjo bolts like the one on the stock filter housing all while still using the tiny stock 450cc/min injectors.

This was on a 34lb/min turbo BTW.

The Fit has 185cc/min injectors, and you guys are running ~24-27lb/min turbos at 5psi and seeing 15-17lbs/min. You are probably just about maxing out the injectors (>80% IDCs) if not the pump as well. Now 9psi would probably put you around 160-170whp or 19-20lbs/min, and you would definitely need an injector upgrade, and I dont know if the 310cc/min RSX-S injectors would be enough.

You also have to keep in mind that you need to have a pump that can flow that much fuel at 9psi above base fuel pressure which is already going to be at least 43.5psi, so 54psi overall.. it is not as simple to say something as general as "the engine can't handle 9psi" because that doesn't make any sense...

Boost is relative. You could certainly run 5-9lbs safely on a small turbo like the HKS or T1R kits using the GT25R in a Fit/Jazz.

But you have to remember 5psi on a 27lb/min GT25R is not the same as 5psi on a 60lb/min GT35R is not the same as 5psi on a 15lb/min GT12.

Boost is only one knob we can turn in tuning. You could run 16psi on a GT25R on a Fit if you have the right tuning tools and a fuel system to support that, and you could do it safely by running very low timing and very rich.

So for example with a GT25R, you could run ~5psi and ~22* of timing to make 130whp, or you could run ~9psi and ~17-18* of peak timing to make the same power at the same AFRs on the same turbo. This is a rough example of course, but an approximation of a common outcome. In my experience pump gas likes more boost with less timing, but if you use water/methanol injection you can run more of both safely.

Theres more to tuning turbos than accounting for boost

 

In this order:

Buy a Turbo Timer, a UEGO Gauge controller and Sensor, and an OBD2 Scan gauge or tool or pocket logger to find out what numbers you are seeing driving around through different weather conditions at 5psi.

Check your spark plugs.

Do a compression and leak down test, you should be able to rent these from AutoZone or NAPA or similar.

Has the car run only premium fuel since being turbo'd?

How many miles are on the car? Do you allow it to warm up for a few minutes and cruise around before hard driving? Do you allow it to idle down for a couple minutes before you turn the engine off?

How often do you check or change the oil?

Since the car is already turbo'd and running well (thats what it sounds like at least) the hard part is done.

If you do everything above, and post the data you have collected from the scan tool/logger we can better help you and more accurately determine if you should keep things where they are or if you can turn up the pump.

Here are some books you should buy:

Amazon.com: Engine Management: Advanced Tuning (9781932494426): Greg Banish: Books

Amazon.com: Designing and Tuning High-Performance Fuel Injection Systems (9781932494907): Greg Banish: Books

Amazon.com: Turbo: Real-World High-Performance Turbocharger Systems (S-A Design) (9781932494297): Jay K. Miller: Books

And here is one you HAVE TO buy:

2007 Fit Service Manual (KA) - Helm Incorporated

In the long run you will thank me.

 

it has a turbo timer installed and set at 1min already, ill have to check into the UEGO Gauge controller and Sensor, and the OBD2 Scan gauge because i dont know exactly what those are.. (this is my first turboed car)
i was told the spark plugs are new i still havent ACTUALY checked them. yes, the car has been running 91 octane since its been turboed and before it was turboed although the car does have about 115,xxx on it.. the oil has been changed with full synthetic royal purple oil every oil change as far as i know. i havent changed the oil yet in the car since ive only had it about a week or two, ive checked it and it still looks new and the car runs great! and i do let it warm up until the cold light turns off before i do any driving. ill definately have to look into those books though!

 

Good! Those are all crucial habits to get into sounds like you are doing things right so far! You'll find that all the time taken to learn as you go becomes fun and a hobby after a while when you understand whats going on under the hood.

The UEGO is a "wideband" oxygen sensor, like those produced by AEM, Zeitronix or Innovate. They are crucial tools for any performance vehicle, particularly boosted applications. This is how you determine what Air:Fuel Ratios you are experiencing.

The scan gauge lets you see into the mind of the ECU and what it is doing at a given point in time, and from that you can establish behavior for certain driving situations. This data will tell you alot about the state of your engine and what the tuning device attached to it is making changes to.

Then at the very least you would be wise to check out your spark plugs, oil, compression and cylinder leak down to assess some of what the data doesn't directly tell us. The rest will be up to your senses after that, which is why I recommend those books to the owner of any turbo or supercharged vehicle.

From this we can determine if everything is good to go, if you are experiencing issues at the 5psi you are running currently, or if you have room to improve!

You will find that your best off checking your plugs every 10k and re-gap or replace them. It's usually only like $12 for some good cool temp range NGK plugs that can keep things smooth and clean.

Since we are 10.4:1 compression and you are raising the boost on a small relatively inefficient turbo, you might want to consider adding toluene to your 91oct or investing in a small single nozzle progressive water/meth kit from Snow, Devil's Own or AEM. This will bring IAT's down and richen the perceived gas scale AFRs by providing not only more fuel on top of what your injectors spit out, but methanol has a richer stoich and higher effective octane (112-114 octane)

 

all in the tune man, theres a tuning company called epic tuning in PA they have a 100% stock d16 running like 20psi and throwing down 375whp, they have all the correct gauges and have one hell of a tune, with a good tune anything is possible

 

what exactly is the water/meth kit? ive read a little about it in other forums but still dont completely understand what it does.. does it put any extra stress on the motor?

 

wow thats amazing, any good tune shops in the Los Angeles area?

 

The exact opposite effect in fact...

It allows any given motor to run the equivalent of a race gas tune.

Cleaner, Colder and it brings its own oxygen to the party.

They are very easy to install and tune once you have a UEGO and a Scan gauge.

 

While that shop has produced an impressive little power plant I wouldnt read too much into fitteds post, it is a little misleading at best.

Those results are not typical for a stock D-series. From what I can find there are 4 or 5 that have cracked into the 300whp range, the highest of which was like 312whp. So one data point at 375whp does not a trend make.

I would put an arbitrary ceiling on the L-series in stock trim around 200-250whp, till we have more people pushing that limit.

The D/B/H/K series engines have more stout internals, and more experimentation has been done. Our weak links appear to be the bearings, pistons, con-rods and rod bolts. While I agree there is alot to be said for their tune, to suggest anything is possible is not entirely fair.

There is probably a list of extenuating circumstances that allowed them that much power, and based on that post alone we do not have enough information to say whether or not that is an apples to apples comparison, I am of the opinion it is not. I am more than welcome to be wrong on this point because it is fun to dream of a stock longblock L15 making such numbers However but it seems highly unlikely based on my understanding and experience.

Since I don't think you feel like pulling the internals on your new car, you may want to try for some more modest power output goals.

Also bear in mind a 1.6l engine @ 20psi and 375whp (38-40lbs/min) tells me that is a decent sized turbo, like GT32R/GT35R sized, so there are extensive fuel and tuning modifications which cost a pretty penny involved in that setup..

They are also probably running 93 octane at the least, and if they are on pump gas it might even have methanol sprayed on top of that. The D16 also doesnt have to contend with the high compression we do.

 

im really liking the idea of this! is the methanol expensive? is there a specific kit you would recommend that i can check out?

 

200-250whp is about my range i would like to shoot for, im not ready to pull the internals just yet.. maybe a while down the road when it needs a rebuild ill get a little more crazy with it but for now i just want a quick daily driver

 

I am more familiar with the Snow Performance kits, because I have had two and still own one.

And the cost/availability of methanol is one of it's strong points!

The methanol can be found in a nice 50/50 water/meth mix in bottles of blue washer fluid at the gas station for like $2/gallon! Just make sure you get the kind that is good to -20F for windshields, and for a 1gallon meth reservoir depending on driving habits you should only have to fill up every 2 tanks of gas. Just be mindful of the level in the tank, several kits come with fail safes that adjust your tune in case you run out, or they have a light you can mount on your dash to tell you when the reservoir is low.

The 50/50 blend part is important because it is not outright flammable or corrosive to the injector feed lines or meth tank, which means that you don't have to spring for PTFE lines which are more expensive.

 

This is very similar to the one I have currently:

"Stage 1 Boost Cooler"
Snow Performance: Stage 1 Boost Cooler?


I will try and get some shots of my set up for you posted later.

Here are some items you should consider to go with it as insurance:

Snow Performance: SafeInjection?

Snow Performance: Safe Injection? Flow Gauge

Snow Performance: SafeInjection? Wastegate Solenoid

Snow Performance: SafeInjection? Boost Controller Bypass Relay

Before ordering, call and discuss your setup and goals with them so they can help you better tailor it to suit your needs in terms of the right injector and components.

 

OP, my turbo (gt25r) peaks at 9psi then drops to 8psi through redline. daily drive it without a problem. tuned with AEM FIC
just wanted to throw out there, as of 4 months ago, i got an email from hondata saying that they had no plans or timeline of creating flashpro or a comperable system for the fit.
my car has 7.5* of timing pulled at peak boost. no knocking. clean plugs. good compression. i dont want to be one of the peopel that finds out teh limits of the engine, but its taking a solid 8psi like a champ.