CarbonXe

iTrader: (1)

Umm, a lean AFR will make more power than a rich one.

Think about a fire. Blow some pure O2 onto it, and that ____ will grow, throw a bunch of logs on it and it will struggle to keep up.

Why do you think turbos run amazingly right before they blow up? Because they began running lean.

Also, if it wasn't for a lean ratio (under 30:1) producing so much NOx, cars would run standard 18-22:1 AFRs. But they won't pass emissions like that, because of the NOx output. More heat = more NOx, which is why at around 30:1, the temps begin to drop off and NOx is no longer an issue. For example, the MazdaSPEED3 runs at 35-40:1 at cruise.

B_Real45

Are you joking? It's been proven that around a 12:1 or 12.5:1 AFR is ideal for turbo gasoline engines.

Air, fuel, and spark all go hand in hand. If you have more air than fuel, then you better have less spark - and all that amounts to less HP.

What increases your hp when you "lean" out the car is your SFC changes. 17:1 is above stoich - you will LOSE power past 14.7:1. Go test it yourself.. I'd love to see the results.

B_Real45

hahahah!!!

Now I know you don't know what you're talking about.. thanks for the verification.

CarbonXe

iTrader: (1)

So you're trying to tell me that fire will burn better when it's colder. Because we all know rich = cold, lean = hot.

B_Real45

Sorry to say but your typical combustion engine is not a bond fire. It's comparing apples to rocks.

CarbonXe

iTrader: (1)

Fire is fire, no matter how you look at it.

B_Real45

You're so off base it's not even funny. I'm done here.

CarbonXe

iTrader: (1)

Sorry I was misinformed, 12.5 is ideal for turbo engines, based off burn speed, but 12.5 isn't the ideal for power for N/A.

thendawg

iTrader: (2)

Alright, so for the love of ressurecting posts from the dead, i am ressurecting my own lol - I have some new info, and wanted to run it by a couple of yall on here that seem to be very knowledgeable on the subject. I have talked with said person (rebuilder of said turbos) and after much looking there doesnt seem to be a 60 trim, at least that hes gotten his hands on that is not water cooled But after discussing the 50 trim with him more in depth he seems to think it would be a viable option. After plotting max rpm on the compressor map it appears i would be at a minimum of 60-65% compressor efficency - which is by no means great but ive been told the standard is to stay above 60% so in theory for a low boost (7-9psi) application this would work. Im not taking the cheap way out as i would spend the same money either way. I just dont want to have to mess witha water cooled turbo setup. I know ill probably get the replies of go for a .57 T3/T4 or what not but hey we are all on different budgets and have diff objectives, this will all be done with high quality parts and all done properly - fuel management, etc, just might not be the highest power output - which is not what im aiming for, i dont plan on anything more than 7-9 psi, EVER, this is still a daily driver and is being boosted only for a little extra fun - not to run 12-13's. In fact if it ever makes it to the track it will only be for fun to see what it does. SO back to the point, does the evo III 16g which seems to be used quite a bit on our cars - isnt it actually smaller? Ive been unable to find a compressor map for it but i would think the 50 trim t3 would do better?

B_Real45

A regular 16g is very comparable to a regular T3 60trim. Some say the EVOIII 16g (has little bit bigger wheels) is more comparable to he T3 Super60.

Just out of my own curiosity - are you just trying to save a lot of money by going with a small turbo and from this builder of yours? It seems like you're trying to use OEM parts to cut down on price. That being said - remember that if you go with a Mitsubishi turbo (16g for example) you'll need a manifold that bolts up to the hotside of that turbo. They are different than Garrett T3 flanges.

If you want a good OEM turbo to start on, any T3 60 trim or 16g would be perfect in my opinion. I really wouldn't go with the 50 trim. It's never good to run past the choke line of the turbo and I gaurantee you will on the 50 trim. There's nothing wrong with using a watercooled center housing. In fact it's more reliable that way. It's not much more tubing to do this. You should seriously consider it.

thendawg

iTrader: (2)

Thanks man, youve been a great help on this, i wasnt really looking at a 16g or a mitsue turbo in general just comparing, and after doing a little more looking i did some math wrong so youre right 50 trim = bad idea and after some studying it seems maybe water cooled would actually be better for longevity, couldnt i just tap into heater core lines for water supply and return?

B_Real45

You can talk with Todd from Turbo Toyotas - he can hook you up with a coolant line setup for a Garrett center housing.

The website is www.whyindustries.net - it's a crappy website but he's very helpful (when he's not so busy).

Syldrin

iTrader: (1)

There is nothing stealth about a BoV even if it is recirculated. it's still loud. the air filter won't muffle the sound at all. if you want somthing quiet run a bypass valve. i'm not 100% sure but i think it wouldn't be as loud as a BoV.

Mr_Meaty

I thought I heard something like that about the speed 3, but I just looked up some graphs, and they run 14 idle to 12 and down when boosting...I think carbon might have been thinking of boost, cause I know they run some stupid high boost levesl for little power!

But he IS right that higher AFRs make more power, but there is a limit. You will get more power boosting at 12psi then at 10psi.

by the way, I'm runnign a 54trim, .63ar on an EL mani and made 252whp at 5psi.

What manifold you going to run?

Mr_Meaty

oh, and with the stealth look...you really still want an IC. Just get one and anodize it black or use radiator paint and leave your grill on...no one will hardley notice.

thendawg

iTrader: (2)

Probably the treadstone cast manifold seems to be a pretty good, durable design. Was thinking of making my own but god thats alot of welding and i dont mind welding but that much all in tight spaces = pita lol

Def decided to go with an i/c btw What turbo are you running, t3/t4 or t3?

Mr_Meaty

Garrett T3/TO4E.
My buddy got the treadstone mani and he hates it...to big, doesn't fit right, DP is expensive as hell and their customer service is garbage.
Talk to Todd at TurboToyotas about a manifold.

thendawg

iTrader: (2)

Ill be fabbing the downpipe myself so no worries there, yea i might reconsider the choice of mani just needs to be priced right, as you can tell im not trying to really take the cheap way out but when im building asetup on a budget it wouldnt make since to spend $450-500 on a mani now would it? lol But as for TT's manifolds, yes they are badass

Mr_Meaty

he's got a simple log style mani as well for $399

http://www.whyindustries.com/store/i...th=23_90_32_75

I think he can make you the DP for it as well for another $300 or so, but don't quote me on that.

B_Real45

Not to start this crap over again - but I just don't want the wrong information flowing out there - people will start using higher AFRs for more power and lean out their engines and break something.

As I had stated before - optimum AFR for a turbo car is 12-12.5:1 AFR. This is assuming you have your tune down to a T. No room for mistakes. If you want a safer street tune then stay around 11.5:1. For a NA car, 12.5-13.3 is optimum.

After stoich (14.7:1) your car will LOSE power. That's what the Mazdaspeed does. Carbon didn't mention the term "Lean Burn" which is what the Mazdaspeed utilizes. This lean burn uses a HIGHER AFR than 14.7:1 in order to LOWER the POWER OUTPUT of the engine. The theory is that this would cause a better efficiency at a given throttle position.

Okay - back to topic. Thendawg - since you'll be fabricating your own downpipe, I'd suggest looking into a quality log style manifold since you're also trying to save on costs. The one Mr_Meaty pointed seems to be of good quality. Dezod (www.dezod.com) has a couple of log-style choices as well.

As for the BOV recirculation - yes it will make it a little more quiet - but MR_Meaty's suggestion of just using a Bypass valve is also good. It will be more quiet and it will be CHEAP. Pick up any Bosch bypass valve and you will be good. Or get a 1G DSM bypass valve.