Showing posts with label racing. Show all posts
Showing posts with label racing. Show all posts

Saturday, January 25, 2020

#ChelseaTheCivic, Part 6-- Race Car Fuel Injector Cleaning Benefits


"Modern" Fuel Injectors

Fuel injectors are tiny valves that feed gasoline into the intake runners or directly into the cylinder of an internal combustion engine.  On some cars, injectors can open and close (one cycle) 50 times per second at engine speeds in excess of 6,000 RPMs.


As wisely stated by Super Street Magazine, fuel injectors are the analogous equivalent to the beating heart in the human body.  These devices can cycle as much as 562,500,000 times in a a typical 200,000-mile Japanese car, and as a result are subject to significant abuse and damage over time.  Needless to say, these components are very important.

An extreme example of a plugged injector.

Use and Abuse

Due to their location, injectors are exposed to unburned hydrocarbons such as gasoline and engine oil, byproducts of hydrocarbon combustion such as soot, and other contaminants.  Heat, vibration, and constant cycling between open and closed states exacerbate the negative affect these contaminants have on injector health.

Another extreme example of a plugged injector

Poor injector health can have a plethora of negative side-effects.  On commuter cars, most people don't get concerned until their car doesn't idle properly or hesitates under load.  These can be side effects of fouled injectors causing inadequate fuel delivery to one or more cylinders.


However, most of our race cars are running in good enough condition that they do not stutter under load or hesitate at idle (at least as a result of poor injector health).  Injectors are important in this context because in racing, the concern is always, "how do we get MORE SPEED!?"

Spencer, Kallie, Dame, and Ken saying "MUST GO FASTER!!!"

But why would clean fuel injectors give us more speed?  Let's cover the basics first...

The Basics of Fuel Delivery in Modern Cars

Fuel delivery to the engine is controlled in a negative feedback loop where the air-to-fuel ratio (AFR) is first measured in the exhaust stream.  The car's computer (ECU) reads the air-to-fuel ratio, and it knows whether there is too much (rich) or too little (lean) fuel going into the engine based on the reading.  Knowing the AFR, the ECU can alter the amount of fuel going to the engine by increasing or decreasing "fuel trim" as detailed below:

When the AFR number is too high, there is a larger portion of air in the exhaust stream, suggesting that fuel delivery is inadequate-- the computer will then tell the injectors to let more fuel into the engine (increasing trim).

When the AFR number is too low, there is less air and more fuel in the exhaust stream, suggesting that fuel delivery is in excess-- the computer will then tell the injectors to let less fuel into the engine (decreasing trim).

Diagram of closed-loop engine operation.

In a naturally aspirated car, an air to fuel ratio of 14.7 is optimal at idle, but under heavy load the optimal ratio varies from ~12-13 depending on application. 

Consequences of high or low AFRs

An engine that runs on the lean side may make more power than an engine that runs a little rich under load.  As a result, some tuners will install adjustable fuel pressure regulators (FPRs) to lower the pressure upstream of the injectors, which will lower the volume of fuel delivered to the cylinders.  For example, on my stock Integra LS motor, AFR at wide open throttle (WOT) was about 12.1:1.  To get more power out of the car, I tuned this to somewhere near 13.3:1.

AEM AFR gauge

So, why not starve even more fuel if leaning out a car will increase power?  Adding more fuel than is needed for optimal power levels means there is more cooling provided to the cylinder in the form of unburned gasoline.  Manufacturers typically want to make their engines last a very long time, so to improve reliability, stock engines typically run a little rich under load.

When a car is leaned out, the cylinder temperatures will be higher, increasing the risk of pre-detonation (fuel combusts too soon before top-dead-center) and damage to the engine.

Diagram of effects of lean engine operation from Laskey Racing

An engine that runs too rich is no good either, as excessive fuel (a solvent) can wash away oil which lubricates the piston-to-cylinder interface and prevents damage and scoring.

The spark plugs can sometimes indicate whether your motor is too rich or too lean


Bad Injectors Are Bad Mkay?

Most engines in sports cars have more than one cylinder.  Ideally, AFR would be measured at each individual cylinder and fuel trim would be changed at each individual injector accordingly.  However, this would increase complexity and cost-- so manufacturers choose to measure AFR in a point downstream of all four cylinders.

Most cars made after 1996 have a two O2 sensors at the catalytic converter.

This means that if one cylinder is burning lean due to a fouled injector while the rest of the cylinders are burning optimally, the computer may not know that there is a significant issue present and may only slightly increase fuel delivery.  Additionally, fuel delivery will be increased to ALL of the injectors which will make the cylinders with healthy AFRs now run rich and the cylinder with a lean AFR run closer to optimal.

What This Means for Racers

So why not install an aftermarket ECU that can measure AFR at all four cylinders in this example and tune it to deliver the optimal fuel volume?  Well, in some club racing classes such as Honda Challenge H4 (HC4) and Spec Miata (SM), it is illegal to run an aftermarket ECU (as of 2020).


So, these racers must find other means to insure the health of their engine and increase their horsepower.  As mentioned above, fuel pressure regulator tuning is a popular technique used to increase horsepower without ECU tuning.  Remember that to make more horsepower using this technique, one must lean out fuel delivery as much as safely possible while the car is operating at WOT.

But how much is "safe?"  In a thread on the MazdaRacers.com Forum, members discussed the benefits of fuel injector cleaning.  One member states that a customer of theirs blew up their motor while on the dyno due to leaning out the car too much.  They sent the injectors out to be serviced and they discovered that one of the injectors was bad.

So, as detailed above, it's very important to know the health of your injectors and to ensure they're as clean as possible before extracting the most power you can out of your engine via FPR tuning.

Decisions, Decisions...

So, you now know how important it is to have clean fuel injectors.  But what should you do?  If you're racing, there are five options that come to mind:

1.) If your car runs, you can send it
2.) You can buy aftermarket OEM replacements
3.) You can do "parts bin tuning"
4.) You can try and clean your OEM injectors on your own
5.) Or, you can have your OEM cores cleaned by a professional shop

Cheap, "OEM" re-manufactured injectors from eBay

Here's why you may want to or not want to choose one of those options above:

Option #1: Send it


Aside from being a funny thing to say, and something people say to appear cool and laid back/chill, "sending it" could be what's right for you.  The other options I mentioned above are not free and do require time and effort-- whether you're researching the best aftermarket replacement to buy, service shop to choose, or DIY method for cleaning.

Additionally, as I mentioned above, most race cars I've seen in lower power classes such as HC4 and SM run perfectly fine with their stock AFRs, offering reliable, fun track time.

When building a race car or tuning one, it's important to attack the low hanging fruit first.  If your suspension or brakes are not up to par and you're on a budget-- save your money and tackle those items first.

Option #2: Aftermarket or OEM Replacements

The beauty of running an older track car like a Honda or a Miata is that there are usually huge, supportive communities and a vast supply of aftermarket parts-- fuel injectors included.

If you go on eBay and look for a set of stock Integra LS injectors, a set of aftermarket re-mans usually go for about $40 with free shipping.  This is an extremely low cost and as a result it is an attractive option.  Amazon even sells cheap, aftermarket replacements for about $45 with one-day shipping!

Cheap "Catinbow" Injectors

The downside of cheap, aftermarket injectors, however, is a lack of specs regarding flow pattern, flow volume, or how closely they adhere to OEM requirements.  Sure, your Catinbow injectors might be 45 dollars shipped in a day with Jeff Bezos' extremely convenient Amazon service, but do you know how well they're made?

As documented on Motor.com, not only is the proper flow rate or pressure important, but so is the spray pattern of an injector.  OEMs pay PhDs a lot of money to determine optimal intake runner design and cylinder head geometry to ensure the best cooling, atomization, and combustion efficiency.  In fact, my rule-of-thumb for most mods on my own race car is to keep as much as I can OEM while still building a competitive car per the rules.


But what about OEM replacements?  They have the right specs and you can be sure that they're going to give you the best performance.

Except, you forgot to consider the drawbacks of owning an old track car-- such as dealing with OEM-discontinued parts.  Even if you can find a set of new injectors for a 20-year-old car, they will likely be costly.  For example, a set of injectors for a 1998 Acura Integra LS (06164-P72-010) goes for about $170.

Fancy but Expensive Injectors

Option #3: Parts Bin Racing

In spec classes, especially, parts bin tuning is a very popular way to make your car incrementally faster.  Parts bin tuning consists of buying multiple used components that you'd like to test and installing them one by one and recording the results.

There are tales of some dedicated SM race shops, for example, buying about 10 old Miata ECUs and trying each one on the dyno to see which one makes the most power.  Another tale is of SE30 racers that buy multiple used MAFs and test each one for the most power on a dyno.


In this instance, we're talking about parts bin tuning with fuel injectors, which was outlined in an article by another fellow H4 racer, Rob Krider of Double Nickel Nine (DNN) Racing.  In Rob's article, he was provided access to an injector flow tester and cleaner.  He then tested multiple injectors that he found at a local scrap yard and picked the most evenly matched and highest flowing ones to use on his race car.  Results proved successful as he made more power on the dyno.

Rob Krider of DNN on the dyno

This technique is probably the most optimal for a class such as mine, HC4.  However, it requires access to a plentiful amount of spares, it requires money for testing the spares on an injector cleaner/flow tester, and it requires dyno time.

As a result, parts bin tuning is usually very expensive.  Therefore, I did not choose this method.

Option #4: Do it Yourself!!!

To my readers' surprise, I actually didn't choose to tackle a project as a DIY for once.  Yes, it's likely the cheapest route, but it takes the most time and results can vary distinctly.

For example, Super Street tested fuel system cleaners on a 210-k mile Acura Integra (DC4) and 190-k mile Mazda RX7 (FC3S).  The results were disappointing.  The injectors on the Integra didn't clean up at all after using Pro-Gard Fuel System Cleaner and not much improvement was noted in the RX7 either.

Pro-Gard

Sure, there are probably better, more thorough ways to clean injectors on your own-- and I have done these in the past.  But they take a lot of time and can be unsafe in some instances.

For example, I once attached a vacuum tube to the inlet of an injector needing cleaning, filled the tube with acetone, hooked up a tire air compressor to the vacuum tube, and then created a power supply using an old wall outlet adapter (AC-to-DC) and some wire crimpers.  Exposed electrical leads and a volatile solvent?  Yeah, I think not...

Option #5: Make Someone Else Do it!!!

Ahh yes, Capitalist America's favorite solution to most problems people face-- if you can't do something, just give someone money to do it for you.  Always works right?

Stupid stock photo because pictures

For this option, you'll need to research the company that is the best for you.  Make sure whoever cleans your injectors provides you with a flow sheet of before and after cleaning results, make sure they provide some assessment of flow pattern quality, and make sure their turnaround time meets your needs.  This all takes time and is a drawback for this option.

Prices for these services are also somewhat high and can range from ~$75 to $100 not including shipping, but when all is said and done, it's cheaper than a new set of OEM injectors, a little more expensive than a set of knock-offs, and the results are more promising than a DIY project.

In case you were wondering-- yes, this is the route I chose for my Civic.

Mr. Injector

The OEM Keihin fuel injectors on my race car were in service for over 170,000 miles and were over 20-years-old.  They weren't leaking and the car was running well.  I also had tuned the car with a fuel pressure regulator on a dyno earlier in the season and it made some extra horsepower.  Yet, I still figured now was a good time to finally have them serviced.

Crusty and Old Injectors

I chose a shop out of Illinois called Mr. Injector after being referred to them by my good friend Alex who is the owner of #TrashTeg and also has been building cars for a long time now.

The Mr. Injector Logo

Bill has been operating his business for over 25 years and it shows.  Turnaround time was less than a week in total, communication was timely, and the finished product looked and performed extremely well.

Can't believe these are the same injectors I sent out!

More pics

More pics again...


A Picture of my son, Pidgey, standing next to a Jolly Rancher and  serviced injector

Along with my new injectors, I received installation instructions to prevent damage to the seals and I received the flow test results from before and after cleaning.  While all of the injectors were (apparently) out-performing the manufacturer-specified 244 cc/min, the flow they were delivering was highly varied.  After cleaning, they all flowed at 260 cc/min.  The biggest improvement in flow was 6% at one injector.

Flow test results from Mr. Injector

A nice bar graph of before and after results

Concluding Remarks

Would I go to Mr. Injector again?  Yes.  I've seen his work put to the test in my buddy's builds and his work was fast and of high quality.  I'm looking forward to installing these on my car and I'm glad I haven't ran into any issues at the lean AFR I'm currently running on my Honda Challenge H4 car.  Maybe I can lean it out even more now!

Thanks for nerding out over injectors with me, readers.  Until next time, have fun and take it easy.










Tuesday, December 10, 2019

EJ2 Track Rat Starts a YouTube Channel!

Over the course of this off-season (at least in the Northeast), you can expect EJ2 Track Rat to be doing some new and innovative things.  For example, EJ2 Track Rat was recently featured on Garage Heroes in Trainings' Podcast.

Working on the Capri
The Garage Heroes in Training Being Garage Heroes

Well, EJ2 Track Rat has created its own YouTube channel with its first video.  The video is already gaining traction as a popular video among the high performance driving and racing community.  

It is entitled "5 Things You're Doing Wrong in HPDE and Track Days"

EJ2 Track Rat's First YouTube Video

When you get a chance, take a look.  There's some great information on common mistakes made by drivers at all levels in the sport.  Feel free to like, subscribe, and comment on the video, or leave your opinions on this blog post!

Thanks for reading.

Friday, October 11, 2019

TrashTeg, The Chronicles; Part 4: Home Depot Racing Sway Bar


Introduction

The Integra and Civic chassis that Honda produced from the late eighties to the early 2000s were set apart from average FWD cars because they could handle well out of the box.  With modification, they could handle even better.


One common problem with FWD cars is understeer.  Because the front wheels are doing the accelerating, turning, and the majority of stopping, the tires tend to "fall off" sooner than their RWD counterparts.  To combat this, FWD race car builders increase the chassis frequency, or "stiffness," of the rear of the car using sway bars or stiffer springs.

Photo of Chelsea the Civic Dog Legging by WindShadow Studios

In this post, readers will see how EJ2 Track Rat was able to create a low-budget solution for drivers looking to increase rear roll stiffness via use of a stiffer sway bar in the rear of the car.

Background

Alex's TrashTeg was driving fairly well.  He was able to pass competition school with NASA Northeast in it and he learned a fair amount about racecraft during the course of the season.  He was also having a ton of fun.  However, Alex was beginning to realize the limits of his budget-built car-- Partially because his car had too much dive, squat, and roll under braking, acceleration, and cornering, respectively.

Photo of TrashTeg Leaning by WindShadow Studios

When TrashTeg was first built, it had the following setup:
  • 205 Toyo RRs 
  • At a ride height of ~5.5-6 inches 
  • With a front spring rate of 650 pounds/inch,
  • Rear spring rate of 750 pounds/inch,
  • No front sway bar,
  • A 25 mm GodSpeed (eBay) rear sway bar,
  • And some Koni Sports he got for free from our friend Anthony
Our goal was to increase the roll stiffness of the car while still keeping the car controllable at the limits with a healthy amount of rotation in corners.  We had two options: increase front and rear spring rate, with a stiffer rear spring rate than front, or increase front spring rate and throw a big rear bar on.

Since I only had a pair of 800 pound/inch springs in my garage, we figured we'd throw the 800 pound/inch springs up front, and increase rear roll stiffness without springs.  The easiest way to do this is with a bigger sway bar, which A-Spec Racing (ASR) makes.  Their 32 mm hollow bars come in different thicknesses and since they're hollow, they have the advantage of less weight vs. their solid counterparts for the same amount of torsional resistance.

ASR Hollow Rear Sway Bar Kit

However, ASR bars are not cheap at ~$500 for a full kit and Alex had already purchased a $300 eBay sway bar kit.  He wasn't about to spend $500 more for the ASR product as a result.  But, he and I were both interested in doing something creative.

Getting Ready for some "Creativity" with a Welder

A while back, I saw a thread on a forum where a Miata driver welded additional metal to his/her sway bar to increase torsional resistance, thereby increasing chassis frequency at the respective end of the car.  

Much debate was had on this thread-- specifically whether one can weld to a sway bar and expect it to work because sway bars go through a forging process that allows them to become "spring steel."  Spring steel is highly malleable, but returns to the shape it was bent from fairly easily.  Welding to spring steel changes that property and increases brittleness.

Example of a Cracked Sway Bar (Not Ours)

Doing the Deed

Since we don't care about armchair engineers and we buy parts for our destined-for-doom race cars on eBay, we decided it'd be worth a go to attempt something similar.  The new setup would have the following changes: 
  • Ride height lowered to 5" at pinch welds
  • Front spring increased to 800 pounds per inch
  • A "custom" xxx mm solid rear sway bar, courtesy of the plumbing aisle at Home Depot
 We started by purchasing some steel black tubing with an inner diameter of 1" and a wall thickness of 0.133" for about $20.  A 1" inner diameter equates to 25.4 mm which is only slightly larger than the OD of our eBay sway bar.  

Our plan was to cut this bar to length so that it would fit between the pillowblocks that mount the sway bar to the subframe.  Then, we would cut the bar in half, length-wise, and weld half of the Home Depot pipe to the sway bar.  This would result in a solid sway bar with a diameter of ~28 mm.


Sway Bar Diagram from ASR

Our Plan from EJ2 Track Rat

We laid out the eBay sway bar after purchasing the pipe from Home Depot and we started by measuring where our addition would be and how short we'd need it cut.

Laying Out the Sway Bar

Next, we cut our Home Depot pipe to length using a cut-off wheel.  Ideally this would be done with a band saw, but with a pipe-vise it's easy to do with a $30 Harbor Freight cut-off wheel.  The cut just isn't as clean.

Alex Cutting Home Depot Pipe to Length

Next we cut the pipe in half, lengthwise using our cut-off wheel and our old school bench vise from eBay.

Cutting the Home Depot Pipe in Half Length-Wise

To weld our cut-off half of the Home Depot pipe to our eBay sway bar, we would need to first clamp the OD of the Home Depot bar to the sway bar.  After grinding the surface of the Home Depot pipe and the sway bar clean, we clamped the Home Depot bar to the sway bar using a set of Milwaukee vise grips.

Half of a Home Depot Pipe Clamped to an eBay Sway Bar

I ran a bead across a section to the left and right of the vise grip, then moved the vise grip down the length of the sway bar and repeated the process...the entire thing was done with flux wire.

Close-up of Beads Ran Next to Vise Grip

The entire bar welded up looked amusing, to say the least.  It really was also great practice for welding.  I needed some, so this was of benefit to me.

Picture 1 of Welded Sway

And Picture 2...

Finally, we sprayed the bar gloss black and mounted it onto the car.  Once on the car, we checked to ensure clearance between our modified bar and the subframe brace was satisfactory.

The Bar Mounted to the Subframe

Checking Fit with Bar at Full Droop

Checking Fit with Bar at Full Compression

And after installing the rear bar, we installed my front springs and manually set ride height as we always do-- the LoBuk way.

Alex Setting Ride Height to Clock Bushings

Another View of Alex Setting Ride Height to Clock Bushings

Impressions

Alex tested TrashTeg at Watkins Glen in October of 2019 with NASA NE to see how the changes improved the car.

Alex Suiting up for a Race at The Glen

On Track, he noticed sharper turn-in due to the stiffer front springs, but the larger rear sway also allowed the car to have less mid-corner push.  The new sway bar we created held up for a full weekend of abuse at one of the best and most demanding tracks in the Northeast.

After our racing shenanigans on Saturday we attended a NASA Northeast BBQ and had a good time.  The car held up, the mods made it faster, and we had a great time.

Me, Alex, Jeremy, and Yuko at the NASA NE BBQ

Until next time, thanks for reading!