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Air/ Fuel Ratio- Results Added!
#624643
04/06/2008 13:41
04/06/2008 13:41
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
OP
Forum is my life
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OP
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Essex
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So, i'm booked in for a RR session at redline Tuning in Basildon. Don't be surprised if you haven't heard of them, no-one has lol I went down there last weekend and he said for the £50 asking price you get a proper printed AFR graph along with the power and torque etc. I'm going to ask him in a mo about bhp@the wheels or fly, a boost graph and do they test for det too as I've read these are sometimes available. Anything else I should be asking for while I'm at it? Anyway, AFR. Reading redline's website it states An engine needs a mixture of fuel and air in the correct ratio; most modern manufacturers aim for an AFR of 14.7 parts of air to 1 part of fuel. At this point the engine produces the least amount of emissions but not the most amount of power.
Typically we try to aim for an AFR of around 12.8/1 to 13.5/1 this is normally where an engine produces peak power. My question, is there a specific figure that a 20vT with the following mods should be aiming for. I'm not having it mapped, but I would like to know if it needs it as soon as I see the results. If it makes a difference, here are are all of my current mods; Hybrid GTiR T28 Pro alloy FMIC Pro alloy SI (K&N 57i) Pipecraft (PowerFiat) exhaust catback Pipecraft De-cat Gtec 1 Armval PRV @17psi trailing to around 13psi at redline. So, for clarity here's what I would like to know; 1), What graphs, figures and results should i be expecting from a good RR session? 2), What AFR mixture should I be hoping for with my current mods? 3), Will a blowing manifold affect any results like fueling? It isn't the dreaded crack (ticking) just a tiny blowing that almost goes when warmed up (Rog said it can happen to manifolds that have been welded previously). 4), What do you reckon it'll make Cheers all, Trappy
Last edited by Trappy; 08/06/2008 01:54.
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: Trappy]
#624656
04/06/2008 13:49
04/06/2008 13:49
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suba
Unregistered
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suba
Unregistered
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You should expect an AFR graph, power, and torque graphs...some places will only tell you the AFR rather than give it to you on a graph - that's fine.
The blowing manifold is not the end of the world - but it is also not ideal.
I reckon the car will make 270 bhp at 1.2 bar.
I would not want a coupe to be running over 12 on the AFR. 14.7 is ideal for NA cars, but for a turbo you want it to be running rich to prevent detonation, and help in cylinder cooling if you are running a lot of advance.
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Re: Air/ Fuel Ratio
[Re: ]
#624683
04/06/2008 14:14
04/06/2008 14:14
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
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OP
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Essex
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Thanks Suba. So it should be 11-12 or thereabouts? when a car is properly mapped, do they try to keep in within these parameters, or do they go for exactly say 11.6? I would not want a coupe to be running over 12 on the AFR. 14.7 is ideal for NA cars, but for a turbo you want it to be running rich to prevent detonation, and help in cylinder cooling if you are running a lot of advance. Another question, what is advance and how do you change what you are running?
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: Trappy]
#624691
04/06/2008 14:17
04/06/2008 14:17
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eldinho
Unregistered
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eldinho
Unregistered
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ignition advance, you will need to get it mapped to change it or for a different chip such as the gtec2/hf!
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Re: Air/ Fuel Ratio
[Re: Trappy]
#624700
04/06/2008 14:28
04/06/2008 14:28
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suba
Unregistered
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suba
Unregistered
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The advance is the point at which the spark is introduced into the engine's cycle: http://en.wikipedia.org/wiki/Ignition_timingThe advance is dependant on the chip - GTEC 2 runs more for example. To change it to suit your car you need to have it mapped properly IMO. Setting the advance and the fuelling is dependant on what you want the car to do and is a personal thing. What boost you want to run / or can run, and the type of fuel used are also factors. Some mappers will set the fuelling at 11.9 or so and then advance the ignition until they hear the car start to det, then back it off. If the car is run richer then you can get away with more advance which can yield more power up to a certain point (you can also run more advance at specific points in the rev range, e.g to spool the turbo faster, and then less at the top end for safety) - you have to balance the two taking the boost into consideration.
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Re: Air/ Fuel Ratio
[Re: ]
#626704
08/06/2008 00:51
08/06/2008 00:51
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
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OP
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Right then, here are links to my results. I tried to get as much data as possible printed out for the forum's pleasure The guy told me that all of the data recorded is stored on his computer and that I can get more print outs at any time. Here you go, oh and by the way, my estimate was 277bhp... BHP & Torque BHP@Wheels & Boost (psi) BHP & AFR
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: Trappy]
#626773
08/06/2008 10:09
08/06/2008 10:09
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Joined: Jul 2006
Posts: 1,671 Newport,south wales
Benny
My life on the forum
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My life on the forum
Joined: Jul 2006
Posts: 1,671
Newport,south wales
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Your bhp and torque are good since you are runing a prv Your AFR is quite lean all through the rev range IMHO you want it mid 11afr Someone should correct me if im wrong, but your next step to rectifie this IMHO would be, Either a walbro pump+ wire mod or a Gtech2 chip or both. Ben
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Re: Air/ Fuel Ratio
[Re: Benny]
#626820
08/06/2008 12:21
08/06/2008 12:21
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suba
Unregistered
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suba
Unregistered
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I think those graphs look spot on, making good power and not ramping up the boost too much. The fuelling is fine IMO - presumably they checked the car for detonation on the rollers? I'd leave the chip as it is as the setup looks pretty good for a plug and play chip.
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Re: Air/ Fuel Ratio
[Re: ]
#626851
08/06/2008 13:31
08/06/2008 13:31
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Joined: Dec 2005
Posts: 2,194 Göteborg, Sweden
Freddan72
Competition Level
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Competition Level
Joined: Dec 2005
Posts: 2,194
Göteborg, Sweden
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Looking good!! Nice to see that you have max hp at 6650 rpm. I have 239.9 wheel hp at 5200 rpm. At 6650 rpm the TB28 has left the efficiency landscape and . I only have 213 wheel hp at 6650 rpm. Next mod for you is a bigger exhaust from the turbo and all the way back, for example a 2.75" Blueflame.
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Re: Air/ Fuel Ratio
[Re: Freddan72]
#626891
08/06/2008 14:54
08/06/2008 14:54
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
OP
Forum is my life
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OP
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I was very chuffed with the bhp figure and rpm. Weird for a T28 eh Torque curve seems very nice too, even if it is a bit low. Weird it is only 238lb/ft right? Saying that it did make 220bhp@ 6,300 rpm and only 216lbs/ft@ 3,900rpm as standard. Seems my coop makes bhp and torque a lot further up than most at the expense of a high peak torque I was a little concerned about the AFR though. The guy did say an option (cheaper than mapping) was to get an uprated, adjustable fuel pressure regular. He said he could get it under 12for under £200 that way? An thoughts on this route? He also said the walbro probably wouldn't solve it? It was his first ever coop though, I think it surprised him to be honest I guess I would want to be running richer before going for a Gtec 2 with more advance right? I also have a wiring mod at home, reckon i should put this on for peace of mind?
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: ]
#627394
09/06/2008 12:44
09/06/2008 12:44
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
OP
Forum is my life
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OP
Forum is my life
Joined: Feb 2006
Posts: 5,390
Essex
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The fuelling is fine IMO - presumably they checked the car for detonation on the rollers?
I forgot to ask them to check for detonation I assume it isn't something that can be seen on any of the graphs I've posted? What causes it and what can be done to stop it if it was?
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: Flea]
#627440
09/06/2008 13:48
09/06/2008 13:48
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
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Forum is my life
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Now you say it Flea, I can see that as clear as day It has to be that causing the little 'hiccup' in the BHP curve. I'm keen to get this sorted out soon and get a few more ponies going through the wheels as it's been a long time since I upped it a little. Where do I start though? From what I know here are my options; Uprated FPRThe guy in the RR shop sugegsted getting one of these if I wanted to improve the mixture a little rather than going for a few remap. I think he suggested this as it is a general trend, not just a spike somewhere in the rev band. (for the record, he happened to have one on the shelf ) If I take this route, would it simply move the whole AFR graph down say 0.5 if i dialled in more fuel pressure or could it leave it all over the place? Gtec2I understand this (as well as the the hi-fuel version) can improve fueling, but it also increases advance- not good unless you are already rich right? On this subject, would every Gtec1 ever made give me exactly the same bhp and torque curves? I mean do different chips vary? I'd hate to get a new chip and then need a remap... Walbro Fuel Pump & wiring modLots of people suggest these in conjunction with the wiring mod upgrade. The guy in the RR shop didn't seem convinced it would work? Thoughts on these one? Wiring ModI also have a wiring mod at home that I have yet to fit. Roger told me how i should take out a passnger in the back seat through the ski hatch to test the voltage getting the the pump. Could this little mod make the difference on it's own? What other options to reduce the AFR do i have to get it spot on, or at least closer to optimum?
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: Trappy]
#627441
09/06/2008 13:49
09/06/2008 13:49
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eldinho
Unregistered
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eldinho
Unregistered
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Re: Air/ Fuel Ratio
[Re: ]
#627474
09/06/2008 14:32
09/06/2008 14:32
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
OP
Forum is my life
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OP
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Shell V-power, Tesco 99ron or at a push BP ultimate, nothing else.
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: Trappy]
#627486
09/06/2008 14:55
09/06/2008 14:55
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suba
Unregistered
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suba
Unregistered
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If you go for an uprated FPR then get one that is adjustable - you can then tweak it a bit to get more fuel in, but it will make the car run more rich throughout the rev range.
GTEC 2 - runs more advance, and wont help at all with what you have at the moment IMO.
Fuel pump and wiring mod - is a good idea for our power level on most cars. If you were running lean only at the top end it would imply that your current pump could not supply enough fuel (top end is where the most fuel needs to go in). As your running lean at specific points I doubt this would help you much at the moment.
To 'fix' the map at the specific points where it is a bit off I would reccomend getting it mapped, but it's not a cheap option and I doubt you would notice a world of difference on the road. If you wanted to go down that route then I would suggest that you go for a bigger turbo (and clutch depending on what you go for), fuel pump and wiring mod and then get the car mapped up.
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Re: Air/ Fuel Ratio
[Re: ]
#627638
09/06/2008 17:57
09/06/2008 17:57
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Joined: Dec 2005
Posts: 2,588 Essex
Rog20VT
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I need some sleep
Joined: Dec 2005
Posts: 2,588
Essex
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i think its too lean, over 12 really is not good for the 20VT.
It should be between 11.5 - 12.0, personally i mapped my car to 11.5 AFR so i knew i had loads of fuel entering to cylinders, and sacrificed a small amount of power.
A fuel pump is not going to solve the lean running, unless your fuel rail is drying up. This can be tested by the RR, very simply, with either a fuel pressure test kit, or crudely removing the fuel return hose and pointing it into a container, whilst running it on the RR.
You really need either a GTEC 2 HF, or get it mapped so it fuels correctly.
or ofcourse, you could lower your boost a little, and that should see it drop below 12 AFR.
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Re: Air/ Fuel Ratio
[Re: Rog20VT]
#627929
10/06/2008 01:47
10/06/2008 01:47
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GrahamL
Unregistered
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GrahamL
Unregistered
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I can send you a Gtec1 high fuel version if you want to try that, just PM me your address.
I'd go for the pump wiring mod as well, for sure, that may sort it by itself.
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Re: Air/ Fuel Ratio
[Re: Freddan72]
#632929
20/06/2008 12:23
20/06/2008 12:23
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
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OP
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I'm sure the Gtec chips overide the 6,800rpm rev limiter. I'm assuming it is common practice for RRs to run the car to the limiter as my graph runs up to 7,200rpm. I think that is what the Gtec changes it to...
I'm pretty sure that when i up the boost ina few weeks, it'll increase the power torque more at the bottom end but leave the curve pretty constant. A GTiR making peak bhp past 7krpm is pretty much unheard of...
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: Trappy]
#632971
20/06/2008 13:20
20/06/2008 13:20
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suba
Unregistered
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suba
Unregistered
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GTEC rev limit is 7,000 as is the case on the standard chip unless you ask grahamL to make a custom version.
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Re: Air/ Fuel Ratio
[Re: ]
#632988
20/06/2008 13:51
20/06/2008 13:51
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
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Forum is my life
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OP
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Suba, why would the RR graph show over 7,200rpm on my runs?
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Re: Air/ Fuel Ratio
[Re: Trappy]
#632992
20/06/2008 13:53
20/06/2008 13:53
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eldinho
Unregistered
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eldinho
Unregistered
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because they didn't match the revs properly I would have thought! Your rev counter maybe out slightly!
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Re: Air/ Fuel Ratio
[Re: Trappy]
#632998
20/06/2008 14:02
20/06/2008 14:02
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suba
Unregistered
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suba
Unregistered
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you sure that your car ran to 7,200, or is that just what the graph finishes at?
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Re: Air/ Fuel Ratio
[Re: ]
#633004
20/06/2008 14:20
20/06/2008 14:20
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Joined: Feb 2006
Posts: 5,390 Essex
Trappy
OP
Forum is my life
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OP
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That's just what the graph finished at. So I should just knock 200 off of those results to get the actual rpm then?
Last edited by Trappy; 20/06/2008 14:24.
F****** b****** thing...
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Re: Air/ Fuel Ratio
[Re: Trappy]
#633007
20/06/2008 14:25
20/06/2008 14:25
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suba
Unregistered
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suba
Unregistered
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I would have thought that your car ran to 7k, but that they had calibrated the road a bit higher - I guess ask them....
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Re: Air/ Fuel Ratio
[Re: Freddan72]
#635413
24/06/2008 18:04
24/06/2008 18:04
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mfcoop
Unregistered
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mfcoop
Unregistered
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Hi all!
Where can i find the stock FPR on 16VT? Please pic.
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