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C20let tuning questions

4.3K views 17 replies 9 participants last post by  DarrenH  
#1 ·
Been doing a lot of searching and can't really find a distinctive answer to what I need to know so though I would chuck up a thread!!

Basically I'm due to get my car back on the road soon after fitting a c20let firstly my ecu is believed to be eds phase 2 but I would like to check myself for safety of my engine before turning up boost and fuel etc what's the best way to check?

I'm on a pretty standard engine with 3" boost pipes fmic 3" turbo back system s114 hybrid turbo rs turbo spark plugs magnecor leads, currently according to my guage it's boosting 11 psi with 13psi over boost

I have got saab reds to go in do I need to fit a fpr or can I just fit them as they are? And assuming iv checked my ecu and it is phase 2 what is the correct boost to run with my saab reds and other mods?

Also iv read something about not using my Amal valve ? Or can that stay put?

Any help would be great I'd hate for my car to go bang lol cheers
 
#2 ·
Best to open the ecu and look at the two chips to see if they are standard or not

You need an adjustable fuel reg really, cant just fit bigger injectors and hope for the best!

Need to have the air/fuel ratio checked to make sure its not running lean on boost.

You can do bypass the amal valve (but leave it electrically plugged in), and use a manual boost controller, you wont get the over boost with this though.
 
#3 ·
Ahhh I heard you had to run 3.5 bar fuel pressure with the boost up abit on phase 2 but wth saab reds you can run more boost still on a 3bar reg? Or is that bollocks? I have an adjustable reg to go on just need a gauge to set it up and to know what the fuel pressure needs to be at

Would you re comment using Amal valve and overboost or manual boost controller?
 
#8 ·
I had genuine evo 2 chips, ran with a manual boost controller set at 1 bar (14.5psi), much prefered it that way over the amal valve with overboost as found it was more predictable to drive.

Had the fuel pressure set at 3.5 bar (vac pipe off), standard yellow injectors and fueling checked with a wideband guage.
 
#11 ·
As a temporary measure, perhaps, but it'll only be 'right' over a small range in all likelyhood and, personally, I'd prefer to set it by EGT as over-rich will be potentially costing power and risking oil dilution.

To answer the original poster's query, you really need to find out what the intended engine and auxiliary specification the chip was intended for and, if changing injectors away from that spec', you may be able to get close to the same fuel flow by playing with pressures, as darren said, but the best thing is to decide on a spec' and have it properly mapped, as you are unlikely to have exactly what the chip was mapped for.

I assume you have the rest of the fuel system up to a standard to maintain the correct fuel pressure at all times?
 
#6 ·
standard yellow injectors at 3.5 bar are 328cc/min (at max dwell)

mathematically youd have to run saab reds at 2.5 bar to get 328cc/min, so theoretically a regulator from the most common 20XE with cream injectors (2.5bar) would therefore suffice, and is a straight swap

eds phase 2 is mapped for yellow injectors though, so...
 
#12 ·
I've EDS stage 2 chips, was running standard fuel pressure (3.0 bar) with the SAAB red's, front mount 2 1/2" boost pipes, standard KKK16 (I think) and 2 inch exhaust system, I made 280BHP, (260BHP at wheels) 280lb/f at Track'n'Road, see sig.

I have 16psi over boost and holds 12psi.

At present I am running above spec plus EDS top hat, and 68mm throttle body, I also modified the cold side of the turbo to flow more air. This setup made 264BHP (at wheels) 272lb/f at Janspeed.
 
#13 ·
Does that mean that I could take off the vac feed to my standard 3bar reg and it'll be good for 3.5bar approx or is that just a rough ass bodge way of doing it?

My current fuel set up is a 255lph pump standard c20let rail and 3bar reg with yellow injectors

I have in a box a reg blanking plate adjustable reg and a set of saab reds but I'm just unsure on what I need to fit and what I don't as iv read a lot of people are using standard 3bar regs so if I could get away with not fitting a different reg it would be easier but which ever I have to do I don't mind I might just give the car and all the bits to a rolling road and let them do it lol
 
#18 · (Edited)
Does that mean that I could take off the vac feed to my standard 3bar reg and it'll be good for 3.5bar approx or is that just a rough ass bodge way of doing it?
the vacuum feed is there to alter the fuel pressure based on manifold pressure.

for example, at idle, throttle closed, there is 0.5-1 bar of negative pressure in the inlet manifold. this physically sucks fuel from the injector tips above the base rate fuel pressure in the fuel rail. so fuel pressure is pulled back to stop this happening (via the hose from manifold to the regulator). at high engine rpm wide open throttle (NA engines) and positive pressure on turbo engines the opposite is happening, the manifold pressure is hindering fuel coming out of the injectors, so fuel pressure is increase to compensate (via the hose from manifold to the regulator)

short answer, no, definitely dont remove the vacuum feed.
 
#14 ·
Basically I don't want to fit my red injectors and an adjustable reg etc to take it to a rolling road to have it set up and then the fuel only needing to be at 3bar anyway because I could of just kept my 3bar reg on it and saved the hassle, if I can fit my saab reds leave the 3bar reg on it and keep my boost around the 10-12 psi mark with 16-18 overboost without it running lean that will be ok
 
#16 ·
There is no easy answer to this. You got to set the fuel pressure back up so you are reading between 10-12 on the wide band at full chat. Best place to do this is on a rolling road (well its a lot easier and quicker to make adjustments on a rolling road).
Basically you will need a wide band to see if your're running lean/rich.
 
#15 · (Edited)
I've got EDS Phase 2 on std K16 with bigger intercooler, saab reds, uprated fuel pump, uprated adjustable FPR, boost adjusted to 1bar (14.7psi), no over boost as such, running on std amal valve. running about 250bhp. Kept this as the K16 is 20yrs old and I drive the car every day, so want it to last as long as possible :)
FPR wise I set it up on the rollers with a wide band. This it was about 3.2 to 3.5bar (vac hose on).
My adjustable FPR is a bolt on replacement. See post here
http://www.migweb.co.uk/forums/engines-transmission/634977-20xe-fuel-pressure-regulator.html#post5099393

PS, EDS Phase 2 usually has a switch to switch the MAP in/out. though not all EDS Phase 2 kits did come with a switch. If they didn't they are usually just copies. If you have a EEPROM reader you can read the last few address memory segments and it should say what version you have.