ka-t af control sudjestions

[Mr. Spool]

I have everything for my kat sitting in my garage. Rebuilt t3, smic, tial wastegate, bov, manifold, downpipe, intake piping, 370cc injectors, oil lines, water lines, The problem I am having is that I can not figure out how to control the af ratio. I was looking to go with the hacked maf, but am a little worried that it might not be safe. I am only looking to run 6 psi. how difficult is it to program a safcII and have it be safe. I tried it once before on my old TT and ended up with more problems than I had bargained for. I plan on owning this car for a long time and would like to use it as an everyday driver. Any sudjestions on which way I should go would be apreciated. Thanks.

[andrave]

if that was me I would go with a hacked mafs, there really isn't anything unsafe about it. If you want to use safc, go with a hacked mafs and then use the safc, then you will only have to use the safc to clean up your a/f's.
with only 370's you could probably get away with just an safc but it makes more sense to enlarge the mafs to compensate first, just be easier on you to tune.

[wpayne]

What you really need to tune the SAFCII well is have an independent knock meter or a/f meter. Yes, I know the SAFC has a knock meter but it uses the readings from the car's computer and it's not too accurate. Then all you do is drive and check every RPM increment (I think it has 500rpm increments) and look to see if it starts to knock at that RPM, and if it does, then add more air(i think that was right). And you do this throughout the power band so that when it does knock, the SAFC corrects it, instead of letting the car's computer retard the timing to minimize knock. I've seen up 15-20hp increase on SR's with an SAFC. Oh, also every car has knock at idle so don't worry when you see some at idle. Good luck.

[Mr. Spool]

Thanks for the info, so it shouldn't be to difficult to tune it. is this safer than running a hacked maf, and produce more horse power than the jwt. also do I leave everything stock to run the safcII. thanks again.

[andrave]

dude, are you talking about detonation "knock?"
detonation kills... waiting for detonation is a good way to blow a motor.
The way to tune properly with an SAFC is not to use a knock meter. You have (HAVE) to tune with a wideband air/fuel monitor.
Preferably in a controlled environment like a dyno. And you have to tune it for the fuel you will be using. Basically you make a few dyno pulls, adjusting the SAFC. But the SAFC can only adjust the fuel at certain windows.
You will have to get a base curve to even get the car to run right with 370's.
If you use a hacked maf it will probably fire right up, and you can use the wideband and the safc to simply clean up the map. a lot less work, and it leaves a lot less tuning...
I don't understand why you think a hacked mafs isn't "safe." does the word "hack" scare you? maybe you don't understand what a hacked mafs is...
anyway, if you wait for knock on a turbo'd stock KA you are just waiting for the piston rings or ring lands to go. And they will when you detonate. Tune with a wideband air/fuel. most dyno's have them.

[kandyflip445]

I agree with andrave. Don't wait till you get a knock. For the reasons he stated.

[Mr. Spool]

the reason that the hacked maf worries me is that if not done right it alows for to much gas, also the timing issue that people have had, somewhat bothers me. I what appears to be a rebuilt engine with perfect compression and I would hate to mess it up. I am looking for the most reliable way to run my turbo set up with the best gains. I guesse another question would be, with a blow through hacked maf, is it possible to have a non recirculating bov or does it still need to recirculate.

[96twofourty]

the reason that the hacked maf worries me is that if not done right it alows for to much gas, also the timing issue that people have had, somewhat bothers me. I what appears to be a rebuilt engine with perfect compression and I would hate to mess it up. I am looking for the most reliable way to run my turbo set up with the best gains. I guesse another question would be, with a blow through hacked maf, is it possible to have a non recirculating bov or does it still need to recirculate.
theres nothing wrong with too much gas....just not enough

[andrave]

as much as any draw through mafs vehicle needs a recirculating bov, so does a hacked maf.
Timing doesn't really become an issue below 7 psi, and you don't have fuel to support more than that anyway. If you want, buy an MSD BTM for 70 bucks that wires into your stock ignition. It will keep your timing in check, the mafs and the safc will handle your fuel.
if you just use an safc, you are still going to need an msd btm or similar device to handle timing. safc doesn't do timing.

[Mr. Spool]

Thanks andrave, I was refuring to the blow through hacked maf, not the pull through. Will a recirculating bov be required. So if I am right in understanding this the individuals who messed up there engines with the timing issue were odviously boosting over 7 psi. so if I keep it around 6 psi I should be okay. Also, with my 370's I was under the impression that my fuel system could handle the more than 7psi.

[andrave]

370's will support.. well that depends on what you are running. with an fmu of course it increases. But anyway on an sr20 with 370s you will run out of fuel at 250 HP or so, from the dyno charts and such I've seen. give or take 25 hp or so.
But if you are going to be close to 7psi, you can leave your stock ignition in but I'd say the extra dollars on the BTM would be well spent. Its not a lot, and people sell them used on ebay for even less. Might want to look into that.

[Mr. Spool]

I am a little confuesed this is the first time that I heard something about the msd. Is it difficult to install. And is it needed to run the 6psi that I want. next is it plug and play.

[andrave]

its not plug and play, nothing on your list is. The only plug and play product would be a JWT ECU.
for 6 psi, I'd have some sort of timing control. stock ignition should be fine, but I'd want to retard timing under boost. there are a few options on how to do that, but MSD BTM is a common one. I don't think its that difficult to install, though I've heard MSD's instructions aren't so good.

[Mr. Spool]

come to find out the tial wastegate I am using is only 4.5 psi. I would guesse that this would change things alittle. What should I use now.

[Grandpa]

theres nothing wrong with too much gas....just not enough

This isn't true either. Too much fuel and too little fuel are both bad.

Buy an afcII or an emanage. Then, either borrow a friend's wideband, or take it to a dyno and get them to tune it to 12.0:1 a/fs across the board.

You will not need to mess with timing at 4psi.

If you don't want to bother with a wideband, go buy a JWT ecu.

-john

[andrave]

I'd second most of what grandpa said... 4.5 psi is so little that you could probably just use an FMU pretty reliably, especially when teamed with an safc and an hour's dyno time.

[Mr. Spool]

I am in luck then I also have an fmu. I was hoping to be able to tune this so that I could increase the boost at a later date. becouse of the low boost, For the time being, I should be able to just run the set up and use the fmu with the stock injectors. until I completely understand the way this is to work for my air fuel mixture. by the way the pipes I am using are roughly 2 1/2 in pipe from the turbo and intercooler. is this to small.

[andrave]

too large for 4.5 psi, if anything...

[Mr. Spool]

You have been quite a bit of help, andrave, thanks. So I should be okay with the size piping I chose. And for my fuel and air just use an fmu, should I upgrade the injectors or leave them stock till I go for more boost.

[IKu]

if you get bigger injectors and use an fmu, your gonna spray way too much fuel. hell, you'll spray too much with just the injectors. upgrade your injectors when you have something to compensate for them. and i think you might need a better fuel pump with the fmu

[andrave]

if your stock pump is in good shape you would be fine (specially at 4.5 psi) but a replacement would be in order. If bigger plans are in your future, walbro has a couple different ones for 75-100 bucks.
If you use FMU and FMU alone you will have to keep your stock injectors. You will need some way to compensate for larger injectors whenever you decide to upgrade.

[Mr. Spool]

So it would be a good idea to hold onto the 370's and the other bits of af items until I decide to go bigger and better, The pump that is in it I believe to be a warbro already. It is ls noticibly louder than the stock pump. will I run into problems with this and my fmu. again thanks.

[andrave]

take the pump out and verify what you have. my walbro isn't any louder than the stock one, and taking it out takes 5-10 minutes so lazyiness is no excuse. shouldn't be any problems with that and the FMU. use a fuel pressure gauge when you set it up to be sure. I'd sure hold on to the 370cc's but you could always give them to me too.

[Mr. Spool]

LOL, I will pull it out and check it. I think I will go with the fmu and which ever pump I have, at first. Hopefully everything should work out.