kponti

At about what rwhp (or more important rwtq) is the need for larger injectors?

For any of the guys who have had their cars tuned and seen any raw data; when do you start seeing 95% plus duty cycle on the injectors? And about what rwhp do you start seeing that?

TheTherapist

Most people will tell you the time to step up to higher capacity is when adding 2 pulleys for instance and your boost starts really climbing but personally I believe anything more than a smaller sc pulley and you're on the edge of getting sufficient fuel if going WOT often. Prevention is better than cure in this respect.

cnterline

I put them in when I went to 90mm TB ,my car dynod at 506 rwhp on a mainline dyno ,03 SL55 car just ran 10.88 at 129 plus last Monday at Atco ,I guess it depends on mods but if your getting up there in hp just do it for safety I used bosch 550cc and I used pigtail connectors vs those adapters they are too close on some injectors,I believe cyl 7 is a btch but that's your choice ,

Hulk

13psi of boost or over go 550cc injectors, with looped rail preferably

RedBullJnky

I agree with this except for the looped rail.

I went 10s with just the EC 550cc injectors and never had any problems. And my twin turbo set up is on the same injectors making 100 more whp and still no problems.

kponti

Loving the responses! Keep em coming.
I now have the 84mm clutched pulley with 82mm tb and kleemann headers. I am looking at going with the 80mm fsp and want to be safe. This is however a daily driver and I don't care to have issues like some are having with EV14 injectors. I will rather change out the pulley to a larger 84mm fsp so I don't have to change out injectors to something less reliable. What do you guys think?

cnterline

I have 168/84 pulleys no looped fuel rail I got the injectors from EC

Hulk

Reason for the looped rail is to equalize the pressure, the SLR was engineered with one so I added it for that reason and since the SLR has more boost it made sense

AgSilver

. . . and the SLR uses 6 port injectors.

Hulk

Actually I think you were the first with the looped rail

Didn't you see a few guys in Germany with a looped rail and then you made yours?

F1BHP

Do you guys know what size injectors the r230 sl600 has and what power would max them out also are they a straight swap for the sl65 injectors.

AgSilver

You know, I don't recall, but I do not believe I was the first. I never saw anyone in Germany with a continuous rail. I sort of got the idea from hearing about the #8 cylinder getting fried (closest to the feed line=lowest pressure) and observing that the SLR's had a continuous rail. I actually had the flex line and AN fittings made by the Mako folks out by Royal Palm Beach, a great company to deal with. Strangely, it took me more than a month to find a master welder in Germany who had the skill and equipment to weld the fittings to the new rail in an O2 free environment and not overheat the area of the existing fittings (I know of at least 6 shops in Palm Beach County that could have done the work).

Hulk

for some reason I thought it was you before it was produced for sale

kponti

SO I have been hearing a lot of really good info but not much on the numbers I am asking.

Let me start, I will say 500rwhp should be a good place to be looking at larger injectors? More or less?

Hulk

Don't by hp, go by how much boost, also your tuner will tell you when you are running out of fuel as well.

kponti

My tuner has been sending me a fresh can of tune from time to time. Since I cannot see what my duty cycles have been, I am left with this in case anyone here has seen when they tend to go in the mid to upper 90s

Your idea of boost is intriguing but somewhat flawed, headers (for example) reduce boost but requires more fuel (duty cycle goes up)

Hulk

No one has every run out of fuel with headers, it's the higher boost that you need fuel for. SLR runs approx 14psi of boost and needs more fuel.

Hp is not a good way to go by since dynos will read differently.

Why don't you get a dyno or road tune instead of a canned tune, that way you will know for sure.

James M

I am no expert on this subject, but I am sticking to the boost theory - anything bigger than a 180mm crank pulley needs 550cc injectors and possibly a looped fuel rail just to be safe.

kponti

Dynos do read different, just like mod combinations have different fuel needs. My aim is to NOT get where I HAVE to get injectors, if my dyno tune says I need injectors I have gone too far and a mod will have to come off. I just want to drive this car like I did my Lexus and maintain (more than I did with my Lexus). I already know that injectors could be a headache I do not have time for and I do not need the power level it will be required so best avoid it.

Posted here just in case someone has actually seen raw data and can say some range I should watch for. I will mod to near there and back off

Hulk

GT-ER posted that info a while back with his mods and where he was going static. Do a search for it. On another note why do you say injectors are a headache? Tuner just scales for it no big deal.

kponti

The Bosch EV14 are known to have issues like issues like dead on arrival etc etc. I have had enough with just welding the Kleemanns to stock exhaust....was a pain in the rear with the amount of time invested. I was willing to pay over $1000 to weld that 2-4 inch gap just so I can get it done and over with especially when the first shop F'ed it up completely.

All I have is 84mm clutched pulley, Kleemann headers, 82mm TB, and ECU/TCU tune. With the exception of the pulley, every other mod has been a pain in the rear with making it work right and required a few attempts. Lots of that required time I did not have to invest into my daily driver.
So in short, I do not want to deal with possible bad injectors and fine tuning the setup cos whatever mods I have needs more fuel

Thank you for the heads up about GT-ER though, I will search for that!

Hulk

A good supplier always has them tested before sending, also if you use the pig tails then install is much easier?

With those mods you don't need injectors

kponti

^^Yeah so far does not look like it, but I will have my wideband installed in the next week or two and see what I am running before I install the 80mm FSP I have sitting under my desk here

SPatykAMG

This does not quite apply to you but I make right around 16psi with 180 lower, smaller upper, 82mm tb, LT, and the red 550 injectors with a looped rail. On a WOT pull I have seen as high as 96% duty cycle. Making right at 500whp and 600wtq

kponti

Thats what I wanted to know!!! Wow 96% with only 500rwhp?