xmodrelic

Excuse the crappy camera phone picture but check out the size comparison.
Obviously the top injector is stock.


I got the upgraded injectors(as well as upgraded wire/plugs) from TVT Design, I noticed some gains, probably in the <or=10 hp/tq range but its more of a prerequisite for the ecu tuning.

There wasn't any instructions with the injectors so I had a few hiccups in the install. First the electrical plugs would not fit the injectors if I kept the metal clips which hold the injectors to the fuel rail, I left them off. Then since the injector are so much larger, the upgrade kit came with new screws and spacers for the fuel rail bolt down. After getting the injectors and rail firmly in place the spacers were to big, so in other words I would have to pull the injector out a bit in order to get the spacers in. This bothered me so I left them off and just snugged the rail down.

I haven't gotten a hold of TVT to quiz them about those issues but nothings leaking, the car has more power and my idle even running smoother. The whole job took about 2 hours, although there was three of us working on it.

babyboigsxr

Nicely done. You got them before me. hahaha

2PHAST

Actually, you didn't need larger injectors, as stock motors never hit full duty cycle on the injectors, even at WOT. Hate to say it, but you wasted a bunch of money on a upgrade that wasn't needed.

I don't know what the flow is on the ones your using, but if you really wanted larger injectors, you could of just purchased C32 injectors, which are 40lb injectors vs. the stock 19lb injectors and are direct bolt in to your motor.

The injectors are also not going to net you any power, the whole point behind increasing the injector size is mainly to address situations where you are hitting 100% duty cycle on the injectors before WOT, this mainly occurs on FI cars, you won't see this on stock cars or cars with simple BPU upgrades.

You really cant use larger flowing injectors without a ECU tune or a piggy back ECU, your going to throw CEL's (long term fuel trim is going to max out)

C32 injector on left, stock on right



Flow test, stock on left, C32 on right

xmodrelic

point taken, I am taking the word of the guys at TvT who had told me over the phone while ecu tuning they were having a tuft time making good numbers untill upgrading the injectors.

I took a good long before and after drive and I definity picked somthing up but I never expected much since it's not tuned to use the larger injectors. Maybe I'm avoiding the point but I'll update this again after I get the ecu flashed.

As for the c32 injectors, that may have been a better choice but new they would have costed the same if not more. The figment issues are minor and don't keep me up at night.

I'm going to find out more info on these injecors and why they wouldn't have use direct fit. They guys at TvT have a few threads open around here and are currently putting headers on a c32, I would think they would be farmilular with it injectors potential.

Don't mind the spelling. I'm on my iPhone

2PHAST

The Kleemann SC and ECU flash net somewhere around 331 hp +/- and the stock injectors are capable of providing enough fuel past redline. Its only after you go past this point that the injectors hit full duty cycle (I increased boost by installing a 76mm SC pulley and was hitting 100% duty cycle around 4500 rpm)

Regardless of what your bolt-on's are, if you are not using forced induction, there just no reason to increase the size of your injectors.

Larger injectors won't give you more hp, only more fuel and that is only usable if you are running out of fuel in the first place.

If your shop suspected fuel problems, they should of pulled your injectors and flow tested them. I have seen them go bad and/or get clogged.

Your shop probably wounldn't sell you C32 injectors anyway, I shouldn't of suggested that option, your car wouldn't even run without a piggy back ecu to dial back the fuel trims, there would be waaaaaay too much fuel (remember they provide twice as much as stock injectors).

Although your new injectors look large, they probably don't flow much more than the stock injectors, a few pounds more at best.

Not trying to beat you up over this, but I want to let others know not to waste money on upgrades like this.

xmodrelic

So what your telling me is not only should i not need larger injectors for bolt-on applications but that unless my ecu is already modified, if I had larger injectors, I'd be throwing a CEL?

TVT_DESIGN

You won't throw a CEL as these injectors are only 20% larger then stock, well within the safe area for the MAF to compensate without a tune.

The physical size of the injector is not what is important, but more the way the spray pattern is and the improvement in atomization over stock. The flow ports are nearly doubled on the upgraded injectors and produce a much finer mist.

When we were doing our research we found the stock injectors (15.8 lbs/hr @ 3bar) to be at 80% duty cycle on a stock motor. When we added a CAI to the car, that jumped up to 82%. When we added a basic reflash the car leaned out and would die at 5200 RPM. AFR readings were in the 15.2-15.5 range.

We changed the stock injectors out for 17 lbs/hr @ 3 bar injectors and our AFR dropped to a safe 14.2. With further tuning we were able to extract additional power out of the combo, and richen the mixture slightly to 13.6 for a safer tune.

The benefits of having a larger injector that is not running at 80% duty cycle are longevity and better atomization to name a few.

Could the injectors support enough fuel for simple bolt ons? Absolutely, but not as efficeintly as stepping up a size.

As for the installation difficulties, they really are plug and play, other then the washers, I just need to provide instructions.

Don't worry about the effectiveness of this mod. My offer still stands to get a CAI done up for your car when you get a chance, and we'll throw it on the dyno for some tuning if you'd like.

xmodrelic

I just need to make an apointment with you guys. I'll give you a call Tomarrow.
Thanks

2PHAST

Hmm, a basic reflash and the car dies at 5200 rpm, sounds like other issues, like your reflash and/or MAF voltage.

Even with a stock Kleemann SC setup, at 6400 rpm, the AFR hits 12.65 (duty cycle on the injectors hit 80% at redline). Only after upping the boost is when I ran into a issue with the AFR hitting 14+ and the duty cycle hitting 100%. How can a stock M112 motor, no forced induction experience high duty cycle and the car dying at 5200 rpm? That just makes no sense at all.

2PHAST

Re-read my post, just like I assumed, your new injectors are only a few pounds more than stock, anything larger and your car wouldn't run, TVT already confirmed that, hence why I retracted my stateent about the C32 injectors, no way you would need that much flow or even be able to use them, ECU reflash or not.

I don't agree with TVT's statements at all, mainly because I spent the majority of this last summer tuning my CLK, testing injectors, flow rates and adding a piggy back ECU and tuning it (for my C32 injectors).

Does not make me an expert by any means, but I can say from experience that if a M112 motor running a sueprcharger, (331 hp at the crank) can run perfectly fine with stock injectors and no more than a 12.5 AFR, then there is absolutely no reason a stock M112 can't either.

You should also do some additional search's concerning the intake, your stock air intake system already flows more than enough air for your motor. You will find that CLK55 owners are actually using CLK320 airbox's as they flow more air then the stock CLK55 setup.

I did back to back tests on my car using a aftermarket filter, a C36 airbox and a stock CLK320 airbox. The C36 airbox netted me another 3-5 hp (depends upon which dyno pull you want to believe ) but the clk320 stock box only lost a couple of HP. So I frankensteined them, using the top of the CLK320 box and the bottom of the C36 airbox. Either one is suitable for a stock motor and quite sufficient for my sueprcharger setup which is running around 11lbs of boost now.

The aftermarket system actually lost hp on the dyno.

xmodrelic

I read that thread and I know the 320's air box has good flow, but were any aftermarket intake true cold air(not ram air or ram air with a divider)? I cant really imagine corrugated plastic tube varying in dia being better then smooth tubing with a k/n cone in the bumper.

Sounds like you've done a lot of work with your car and I don't doubt your intention of keeping the community informed, there may be more variables working here then your experience extends you. In the end all I care about is what I get for the money and as long as I get solid gains I'll be a happy customer. I will keep this thread updated, I don't want anyone wasting their money but I feel confident enough to give them a try.

babyboigsxr

Okay guys, sorry to break the flow of your conversations, but i just wanted to know....

if my ECU has ALREADY BEEN REFLASHED, is it a good idea to get the TVT Injectors? What type of gains would i expect?

Would you like to fill me in on this TVT?