I posted this in the rtek section, but we all know how much attention that forum gets, lol. Anywho....

So I'm about to buy an rtek so I can raise the boost, but I'm not sure which to get. Is the 1.8 really needed for 12lbs of boost? Do I really need 720 primaries? I know Digi7ech has the 1.7 and I think he's running 10-12lbs. The only diferences I see in the 1.7 and the 1.8 are the primary injector sizes. I'm wondering why that is, and at what point do you need that extra fuel?

I have a rebuilt and street ported motor, not sure if its all s4 or mixed parts internally, 3" full exhaust, 3" tid, and an fmic being mocked up at the moment. With a boost controller running 10-12lbs would I need the extra fuel that the 1.8 supports? Given more fuel is always safer, I still don't want to be wasting it. Any opinions?

 

I didn't think the 1.7 was still available, I thought it was upgraded to the 1.8 but you can always email Mike at Digital Tuning, he is quick to respond and knows the ins and outs of the software better than any one on here, he also had a membership on here, turbo2ltr I think.

I would recommend going for the 2.1 if you are over 10psi, it just opens up so many more options for tuning down the road.

 

I used to run the 1.7 at 12psi with 550/720 and an FMIC. but you need to make sure you have your fuel pump rewired.

 

The 1.5, 1.7 & 1.8 all give the engine exactly the same amount of fuel. Fuel corrections are made to accomodate two or four 720cc injectors, and it's done in such a way that virtually no part of the fuel map provides more fuel than stock. The only point that does have more fuel is the injector transition point, where 5% was added in to remove the lean spot that can happen there. The upside to the larger injectors is that you'll be running them at lower duty cycles. I know from datalogging that 550cc primaries will hit max duty cycle if the secondaries don't come on by about 3600 RPM. Fortunately, pocketlogger moved the transition point down from the stock 3800 RPM on the chips. As for secondaries, I only hit 70% D/C at the most using 720s. 550s would be nearly maxed out too at high RPM/boost. The biggest boost to fuel you'll have using any of the three chips will be from the fuel pump. A bigger pump will be able to flow enough fuel at high boost pressures, so you don't lean out on the stock/Rtek fuel maps.

 

So assuming I got the 1.8 and put in say 850cc's or something similar, couldn't I tune it with an afc or something so that it's not overly rich? And with more fuel the duty cycles wont be very high either I'm assuming.

 

Sure, you can take roughly 20% fuel out of the entire Rtek 1.8 map to run four 850cc injectors, but that's really overkill. 550/720 is plenty for the stock turbo, although I have my injector staging set very low at 3100 RPM to keep the primary D/Cs from spiking under boost. Without the benefits of the stage 2 Rtek, using four 720s & an the 1.8 should keep the duty cycles below about 65-70% at all times.

 

What im concerned about is whether or not I'll have enough fuel in there to compensate for the street port. So if im boosting to 10psi i wont detonate.

 

I ran a street ported s4 at 10psi with stock tune,walboro,stock injectors and it was just fine in fact it was real rich for the most part it would lean out right at the end in a high load like 3-4 gear. you should be safe, but just get a wideband and you will know all the time

 

I have rtek 1.8 with four 720's and afc neo. My car cuts out as soon as it hits any boost.. Could that be the rtek 1.8 or fuel pump needs to be rewired?

Omixeo I only got the rtek because i got a good deal on it... If i were to buy brand new without a doubt i wud of gotten the rtek 2.1..

 

A streetport combined with the stock turbo will do very little in terms of power gains. The stock turbo can't flow enough for the larger ports to reach their potential at high RPMs. It starts to restrict the engine even with stock ports. So I don't think I'd be worrying that the stage 1 Rteks would run lean. Although a wideband is always a good idea.

If you do end up going with 850cc injectors all around, the Rtek 2.1 will give you a lot more control than a 1.8 & an AFC. You'll be able to log your AFRs along with all engine data, and make fuel corrections much easier. Not to mention, you have full timing control with the 2.1.

 

RR88 is right on here, the Rtek maps are basically stock but they give you more safety assuming the rest of your fuel system is up to the task. And yeah the 2.1 really makes it easy to tune your car if you have a WBO2, you can log your boost, rpm and AFR's and go directly into the maps to +/- fuel where needed. Much better than trying to eye the WBO2 and play with an SAFC....

TOOSHORT 88, is this the FC with the FD UIM your talking about cutting out? The Rteks are supposed to eliminate fuel cut and shouldn't be causing any problems for you. If your fuel pump has not been rewired I would start there and make sure your pump is getting proper voltage under boost. I rewired my Walbro and noticed some nice differences in the AFRs, though at idle it was initially pig rich, I just had to trim the maps at idle and it was much better. You don't have to add as much fuel in the maps when your pump is really running right either.

 

so lets say, i do a BNR Stage 2 on stock porting with a v-mount set-up, full 3inch exhaust and a Walbro 255, and i wana run 12-15 pounds what version would i need, can i do the 1.7 with 720 primaries AND secondaries, or should i go up to the 850s? or do i have to go up to 1.8?? cause im a little confused myself

 

Go to www.pocketlogger.com for all the details.

Rtek 1.7 is set up for 2x550 & 2x720cc injectors.
Rtek 1.8 is set up for 4x 720cc injectors.

IMO, you'll run out of fuel if you only use 720cc secondaries. And running 850s would give you lots of headroom, but you'll run way too rich without an SAFC, Rtek 2.1, or standalone EMS. The stage 1s are not adjustable at all on their own.

 

go rtek 2.0 or up - a few better upgrades that make it worth the cost

and, with the 1.x series - you have to run the specified injectors, because it has a pretty solid base map.. - if you dont run the specified injector sizes - you'll have to to modify the entire curve to make it run smoothly - plus you cant change the fuel at idle (i believe the +/- curve starts somewhere around 2100rpms).

 

i am about to receive my rtek1.8 tomorow and i currently have 550 primaries and 680 secondaries.... i was planning on finding the right 720's but it seems i would run short on gas no? i have 3" straight pipe, FMIC s5 turbo modded tb all emmissions removed, efan, cold air intake, i have beaten myself in the head for just not getting the 2.1 in the first place ugh!!
ps currently pushing 11-12psi... would i be good with 680 all around and meth injection?@12 psi?

 

Do not use 550cc injectors with an rtek 1.8. You will run lean and detonate. Using four 680cc injectors is pushing it as well, since you will be subtracting 6% from the entire fuel map (680/720 = .94). Get an AFC to add fuel back in, or better yet just use 720s. The meth injectors may put you in the clear, since it is a fuel itself, but you'll have no way of knowing unless you have a wideband. Of course, you should really have some way of tuning anyway if you're using meth injection.