KhanArtisT

iTrader: (2)

So I finally got a wideband to see what the AFRs are like, the setup on my car is:

Engine and Exhaust

S5 turbo (52mm wastegate)
S5 turbo manifold w/ 2.5" spacer and frame notch
3" downpipe, 2.5" Y
2" to 2.5" IC piping
Turbo XS RFL BOV
Front mounted stock TMIC
Stock engine, stock ports, Kevin Landers rebuild @ ~50k miles
123psi F
120psi R

*TII drivetrain/stock clutch + FW

Fuel System and Engine Management

550cc injectors x 4
FD fuel pump
S5 TII ECU, MAP, AFM
No stock O2, no IAT
6psi (drops off to ~5@ 6.5-8krpm), creeps to 8psi in 4th

Now the AFRS:

Idle: 10.4-11.0
Cruise: 12-14s

WOT: 1st/2nd gear it starts out at 11s from 3-5k rpm and dips all the way down to 10.0s (probably 9s since the gauge reads no richer) where it kind of falls on its face from 5.5k to 8k.
3rd/4th gear they're slightly leaner ~+.4-.6
Haven't gone in full boost in 5th yet, I was scared it would lean out...will soon though.

I know that every car is different when it comes to AFRs but I definitely believe that you CAN run the stock TII ECU and sensors on a 6 port turbo setup, at least S5s. I've been driving the **** out of the car for the past two months probably ~5000 miles and it runs great. I'm taking the Super Street course at my school starting tomorrow so I will post up with dyno numbers soon.

arghx

iTrader: (3)

why on earth did you get rid of your IAT and O2 sensors? They are there for a reason and there is no performance benefit from removing them. It's part of the reason why you are getting bad gas mileage.

And you should try and adjust the variable resistor to lean out your idle, since you have a better flowing fuel pump than stock. It can idle as lean as the low 13's if you have stock ports and it should remain stable.

KhanArtisT

iTrader: (2)

The clips on the IAT broke and I didn't bother getting another bung welded on the downpipe for the stock O2, I may run the extra simulation wire on the EUGO if it really gets to me or when I'm bored. The car is not a daily driver.

No variable resistor, car is an S5. BTW this thread wasn't made to "troubleshoot" the rich AFRs but to show that a 6 port turbo setup can run safely without a standalone or even any fuel tuning for that matter, albeit rich as hell. I posted about using a stock ECU until I could afford a piggyback and was told that my engine was going to blow up

arghx

iTrader: (3)

I would not recommend you try to lean it out with an SAFC. Due to the lower airflow signal, that will result in more timing advance (which you already have too much of for those 9.7:1 rotors) and increase the chance of detonation further.

KhanArtisT

iTrader: (2)

Ah I didn't know that, it makes sense.

Funny I mentioned blowing my engine because thats exactly what I did today, lol. I drove it to school and it drove fine, (passed through a closed road and set up a course) did a 120mph pull and it pulled hard at 8psi pushing 10.4s on the wideband. Parked it, came out and it didn't want to start, straight cranking and no start. I troubleshooted everything and had it towed home to check compression which was roughly (cold):

F: 90/90/60
R: 5/5/10 (?)

The only symptoms I got was it gurgling when I shut the car off...it would do it for a while after I shut the car off but only on the coolant line coming out of the turbo so I thought it was the turbo. But it never flooded on me or anything, few days ago it pushed 120psi on both rotors. I'm thinking its either me having hit fuel cut over 8 times (cold nights/setting boost controller/boost creep), 3 of which I felt it detonate, or maybe air pockets being created from the gurgling causing coolant temps to shoot up (although the gauge never moved from the middle).

Black Knight RX7 FC3S

iTrader: (7)

did you try any unflooding precedures?

arghx

iTrader: (3)

it's just too much timing for those rotors

dawicka2

That sucks, man. Sorry to hear about your engine. Those were definately good starting compression numbers, At least this will be a lesson to future 6port turboers regarding timing.

Are you gonna rebuild the 6port or put a t2 engine in?

john ny

Black Knight RX7 FC3S

iTrader: (7)

did you ever retard the timing? if you did, did you use the cas to do it?

KhanArtisT

iTrader: (2)

I never retarded the timing. Every single time it detonated it was because of fuel cut, I really don't think the timing was the problem. Reason being that if it were the timing it would've detonated on its own, and the only times it detonated was in 2nd gear at ~5500rpm when it wasn't even pushing 8psi, more like 6. There was the typical boost spike you get from an MBC (home depot) when you go into boost...where it would spike to 8psi then drop to 6psi and hold it till 6.5-8k where it would drop to 5 so maybe that did it. I also think it had way too much fuel (9s on the WB) to detonate...

I tried all the unflooding procedures, pulled the plugs like 5 times, EGI fuse, drained my Optima yellow top cranking that bitch, lol.

As for the car, I'm moving to another apartment in 4 days, my friends house (where I can pull the engine) is an hour away, I just spent $150 on this tow and $1100 on this drivetrain. With the $2000 I have on my CC I think I will have to cut my losses and sell the car and start over once I graduate...but we'll see. I'm definitely putting another S5 6 port engine in it.

jackhild59

iTrader: (7)

Sorry for the loss of your motor. One bit of advice that could lessen the blow next time- Never hotrod on borrowed (CC) money. Now you have a 2-grand debt and no car.

There's nothing worse than a non-running car that you owe money on.

Take it a little further and strive to avoid all debt, except prudent mortgage debt. There is NO good debt and very little acceptable debt. You should never incur debt for a car.

Not preaching, just sharing my life experience.

Good Luck!

Roen

iTrader: (2)

From what I've heard, S5 ECU's don't really get affected by CAS adjustments.

KompressorLOgic

iTrader: (6)

yeah it does. the ecu reads the cas to get a base timing number, and then the other sensors manipulate it based on boost, load ect....

So if u adjust the cas it throws off the whole timing map by how ever much you turned it in advance or retard.

Roen

iTrader: (2)

From what I was told from my rotary mechanic, in all his dyno tuning experience, he's never seen CAS adjustments make any power on S5's. In his view, the S5 runs off the maps only in the ECU.

Personally, I think adjusting the CAS affects the timing, like you said, but I've learned to listen to my mechanic and his 20+ years of rotary experience.

somebody5788

It wont effect your peak hp but you can try an prevent detonation w/ it and that was the entire goal here.

AlexG13B

iTrader: (7)

sucks to hear, could have been maxing out those injectors as well with that type of AFRs and stock 550s all around,
timing could have played a roll as well and heat. high comp rotors produce alot of heat and even more under boost.

MazdaRX7.ws

Hey man sorry to hear about your engine. I read through the whole thread because I still have my 6 port turbo. I just don't drive it. Just sits in my driveway under its car cover! Now I am scared to drive it... Can someone explain something to me? When I bought this car and I was driving it back from NC it was going from 3rd to 4th and I pushed it a bit maybe half throttle and as I let off the gas to go into 4th.... Holy **** it sounded like a f*cking cannon! No **** everyone was looking! Is that backfire? Is that detonation? is backfire detonation? If not whats the difference?

KhanArtisT

iTrader: (2)

Thanks, it makes sense but at the same time I think I benefit too much from being able to mod the car now using the CC vs. when I graduate because I'm attending a vocational school from which you will learn nothing if you can't apply it onto your own car. The only good reason to do it is because I take interest in the car, I wouldn't have the same motivation to do it to work on my Corolla wagon...Plus this thing has an $8000 limit with a minimum payment of $15.00 every two months.

I have an extremely reliable daily so thats not a problem. I worked at DHL for 6 months until they went out of business and am now receiving $275 weekly checks from unemployment with no bills to pay (parent funded rent) besides food/gas so I don't think the two grand will be a problem.

As far as the CAS I had it retarded one time and the car ran like complete ****. I had it off by a degree or two once (adjusted at wrong idle speed) and immediately noticed a difference after resetting it so I think it does affect it.

xboxthug13b: I'm not sure I understand what you mean...if the actual AFRs were in the 9s/10s that would indicate the injectors are spraying fuel consistently enough to achieve them. Also factor in the 20psi+ higher output of the FD fuel pump vs. stock which = higher rail pressures.

Well thanks to the large population of rotorheads in this area I am getting way too many offers of engines or parts to sell the car...I will probably get another used engine and throw it in, drive it slowly until I graduate and go full rebuild/T4/EMS/AI.

KhanArtisT

iTrader: (2)

Just keep the boost down if you are worried, run it off the wastegate spring. If the hesitation or backfire occurred under deceleration (when you let off) then it is just backfire, don't worry about it.

Roen

iTrader: (2)

Just wanted to clarify so as to not misquote my mechanic.

"In his view, the S5 runs off the maps only in the ECU." was a bad misquote on my part and should be disregarded.

gxl90rx7

iTrader: (1)

actually your fuel pressure regulator should keep your fuel pressure just like stock, even with aftermarket fuel pumps

the CAS is a crank angle sensor for the ECU. The ecu timing maps stay the same, but you are advancing/retarding teh whole map when you adjust the CAS. the stock maps were designed with the CAS at -5 degrees Leading, there is no feedback. I think anybody runnign a 6port turbo setup on the stock ecu definately needs to be retarding the CAS by 5-10 degrees, stock timing is really advanced, especially for n/a

AlexG13B

iTrader: (7)

well i mean the injectors could have been maxing out, duty cycle reaching high.
my old t2 i hada megasquirt in with fd pump and 550cc injectors and i would see very high duty cycles under boost (sometimes even 100%!!) at 10 AFRs.
not saying that was your cause just something that is a possiablity.
causing them to reach that high could have caused one to fail.

KhanArtisT

iTrader: (2)

As far as I know FPRs are configured to work with a stock pumps, meaning it can only bypass enough fuel to keep predetermined rail pressures from the stock pump, anymore pressure from the pump (with the same voltage) and you have pressure spikes up top, hence the reason people upgrade to RR/Adj. FPRs but I could be wrong since I learned that reading here.

Most 6 port turbo people don't run the stock ECU though, even though its tempting considering the 2.0 is out only for the S5 NA's.

I just want to make sure that it was the detonation from the fuel cut that really blew this engine...The first few times I hit fuel cut (S4 26MM wastegate) it would usually hesitate and I would let off. The last few times it happened I would hear a loud clunk from the engine following the hesitation. It never detonated or hesitated once when it didn't hit fuel cut.

NotTTT

Of course it does! Remember that time @ my place when you were too much of a sissy to grab the CAS becuase it was hot and I had too? Awe, Kitten with the soft supple hands had to work the timing light Whenever the CAS rotated, the timing followed. Now, your mech might be saying that the timing in the S5 ecu is so spot on that adjusting it won't make a difference.

Ignoring the pisspoor use of credit and not understanding what minimum payments are about............. on to timing

Your 6-port turbo at idle is an S5 N/A car. Let me say that again, your turbo car at idle is an N/A car. Think about it.

Your N/A car @ idle and vacuum needs n/a timing to run properly which is why the timing needs to be spot on for it to run decently. When you get into boost and the higher load points in the MAP, the timing needs to be retarded. The Stock ECU can't do this and pop goes the rotary. If the Rtek's timing map can be adjusted based on load and AIT (which also have an effect on the timing needed) you should definately go that route.

To a certain point. It is possible to overrun the stock reg with a big enough pump. How big is big enough? Dunno

True

True, but read my post above regarding n/a timing and why some sort of EMS that can adjust the timing based on load is needed

KhanArtisT

iTrader: (2)

Ignoring the highly opinionated remark regarding use of credit...

This is a very basic concept on how timing works and is understood by most people. It is the reason most people switch to the TII ECU and MAP+AFM on 6 port turbos. An EMS is always a better route but the stock ECU is a cheaper alternative provided that you run the proper safegaurds (low boost, 93, avoid high-load/low RPM conditions)