You all are confusing the crap out of me! I want to upgrade my FP and Injectors to support a T78 or big Garrett. What size/brand is safe? Is there anything close to a consensus on this issue? Should I just add the external intake/rail with additional injectors instead? WTF, you guys have been wrenching on these cars how long? My endless searching is making this worse.

Reliability first, performance second and confusion always!

 

hey guys, figured I woudl chime in been busy with my BLOWN engine

anyway, I got my 1300cc from Rotary Xecret, but they are just sent to RC enginerring. I have a print out from RC stating the flow rates. one was 1300 and other 1305.

Tim, I really am not sure that those injectors blew my engine. I know what you are talking about in the dataloggit forum many have stated hesitation with large injectors, obviously hesitation is a lean condition for a few secs. I know 1300 and larger will more likely cause a stumble, but 1200cc were on back order too long.

with the datalogit you have much more control over injector settings, there shoudl not be a problem. I don;t think my engien blew from injectors I was at 5lbs of boost at 3300rpm. Again I doiubt it was teh injectors failing as I was experiencing the same thing before theyt were installed, but who knows, I guess we will find out if I blow up my new 3mm street-ported engine

 

that's the kind of response I was hoping for, thanks Phil. Something that dispute the obviously overstatement I made about the injectors. Phil was having the same problems before the larger injectors were installed, so maybe they aren't a problem, thanks for posting Phil and hope to see you back out before you head back north.

Tim Benton

 

my $.02

I've lost 2 engines since my 850cc/1600cc swap, both broken apex seals from detonation.. Part of this is I like to push the limits of the shitty gas whe have over here on the military base, but here is what I think is happending..

Due to the larger amount of possible fuel and the injectors being very close to the port. I don't think the fuel is atomizing very well. This will causes lean spots in the cumbustion area and incomplete burn of all the fuel during the combustion cycle. That extra fuel is being expelled out the exaust, throwing off the A/F ratio.. so basicly what your getting out the exaust is a 12.5:1 A/F ratio and a bunch of unburnt gas... I'm gonna tune my next engine to a 10:1 ratio to start with and see if I can find some way to get better atomization of the fuel with out having to move the injectors...

What I'd love to see sombody make is some stainless steel injector diffusers that will optimize the spray pattern of the 1600cc bosch injectors and they wouldn't break like the shitty stock plastic ones... sombody

 

Dragon, the best way to improve fuel atomization is to raise the fuel pressure. The stock fuel system is built to handle much more pressure than it has. Generally the larger the injector, the more fuel presusre is required. to be honest even 1300cc is too big for 15psi on stock twins. I should have gove 1050cc with rising rate fuel pressure . That will ensure the best atomization and power. I think 1600cc on stock fuel pressure is crazy, you are right about poor atoimization. just bump the pressure up and you shoudl be okay. I would like to find out from RC or somebody about what the optimal pressure and duty is of the enlarge secondaries. Since they are just bored out, we know we are getting poorer fuel atmization with same pressure.

 

I was having the same problem, but it didn't pop until new secondaries. Like I said I doubt it had anythign to do with it, but it may, you never know. I was actually seeing richer readings, so if it did it woudl haev had to be at transition.

BTW, I am pulling engine this weekend, and putting new one in the next weekend. If you get bored, I have plenty of beer and ****, and I may need an extra hand to pull it. Let me know, my datlogit will be sitting here doing nothing for next few weeks as well, so you can borrow it if you want. You may have already bought one, I don't know.

 

Would intake mounted injectors supply better atomized fuel? If so, would it not be a better choice to go with external additional injectors rather than larger secondaries?

 

Hi, gang. I've been using an upgraded pump, 1300cc injectors, pfc, m2 medium, upgraded twins, pettit intake, dp, resonated mp, and cat back for over 6 mos. now with no issues. My first dyno tuning session was for the N/A area to pass smog, but did some high boost runs (with the cat on) and ran 10:1 afr even after I took some fuel out. Ran 274 hp at the rear wheels with the stock cat on. I've had no detonation, hesitation, or issues - car runs strong and I'm very happy. I need to go back and tune without the cat and concentrate on the higher boost quadrant, since I've seen others with the same mods get into the 360 rwhp range using this setup. I'm assuming I'm choking on too much gas and might need some timing adjustments.

My pfc and 1300cc injectors came from SR, btw.

 

Phil,

what day this weekend? Sunday is the mountain drive so I'll be on it, unless I stop by on the way back in from North Ga, down 400.

Tim Benton

 

I'm running 45psi at the rail right now, 60ish under boost.. actually raising the fuel pressure caused the injector transition stumble to get worse...

 

For those of you using 1600CC inj, what are the lag time setting are you guys using. I'll be using the stock 550 pri and 1600 sec with a RRFPR. Also give your setting for the

Pri/Secondary Transition(%)
Sec Transition (ms)

Thanks for any info.

 

Has anyone had their "1600" injectors flow tested yet, to see if they flow 1600 cc/min or 1680 (as the 160 lbs/hr conversion works out)?

-Max

 

I installed 1300s last week and its been fine, they were 33000 mile injectors sent off to RC for enlargement. They are powered by a big bosch intank pump. I am experiencing more fire out the tailpipe on an inverse engine load and puffs of blue smoke on the upshifts when pushing it hard. I think in just needs some more tuning. Im planning some dyno time the second week of May at Automechanika. Stay tuned for more.
1R1

 

1RedR1/Pep is using my maps which have been posted on the Datalogit forum. Yes, they're indeed too rich and I plan on hitting the dyno in the not too distant future to take out even more fuel. I did lean out the lower boost settings a bit and uploaded that map along with modifications to my timing tables based on XS's map.

Remember, the stock car (at least some did) had a 3K stumble. Many theorized it was the secondaries kicking in and causing a RICH condition momentarily, not lean. I think it's the same when you go with something like the 550/1300 combo I'm running. In my case I get a slight blip at about 2200rpm when I mash it in a tall gear. Other than that, my 1300's have given me no issues and I've been running them for over a year I believe.

FYI, those maps produced 340rwhp on my car. Last Friday I hit the 1/8 mile (no 1/4 mile near me!) and smoked a 405hp Z06 by .4seconds and 5mph. I ran an 8.2 at 90mph on 18" rims/Kumho 712's with a 2.1 60ft.! Crap! On BFG Drags with a soft launch (stock differential you know) I can run 7.8's at 92/3ish. I'm pretty hard on my car and I really feel as though it's not an injector issue (at least with 1300's that have been modified correctly). The 1600's, like Dragon said, may have an atomization issue which could be solved with a larger, higher pressure pump.

Ehuges, I'd do an 850/1300 combo with either the high flow Bosh or the Walbro GSS-341 255lph highflow/pressure which I run. You should have more than enough fuel for 450-500hp with that setup.
Michel

 

i have an idea.... split the line before it hit the primary rail..... and run 1 to the primays and 1 to the secondaries thenmake the return to one.

 

Many people talking about the secondaries coming online being the 3k problem. Well this is true ... the secondaries cycle on and then off and this caused the stuble. The 1680cc injectors are just so large that the tuning has to be right. There are plent of people that have gotten the 1300cc working good and even better with datalogit tweaking. I'm working on getting them tuned in w/ 550cc on a signle turbo. I have them coming online smoothly above 4.5k but not between 3k and 4.5k. If you roll into the throttle it is smooth but not if you just go immmediately to WOT.

Oh yeah, for right now I'm running 0.05 injector lag time but I'm thinking of decreasing it.