Big 16g max on 93 octane?

[4gfun]

Alrighty I am new here and I have searched through most of the 409 threads or so that pertained to this in some way or another.

This is my 2nd 91 TSI AWD that I have owned, and I would like to say that the information that I have seen here concering tuning is light year ahead of some of the DSM forums that I have seen elsewhere. I wish I knew about this forum yrs ago!!

With that said, the car has the following mods (I must be vague in some areas, because I have limited information from the previous owner):

Centerforce DF clutch, Fidanza Flywheel, Big 16G port matched to 2G manifold, ported and polished head, bigger cams, Galant VR4 1st Gear, K&N, Apexi SAFC, Apexi Exhst, Autometer Boost Gauge, EGT Gauge, Palm iiic with mmcd, SX AFPR w/ gauge, Walboro 255, MBC, JE Pistons and Eagle Rods, 2G Exhaust Manifold, SS Brake lines, ported O2 housing, JSPEC transfer case & tranny, modified fuel rail.

My question is this:

What is the max boost that can be run on 93 octane on a 16g if knock and A/F are in control?

I may not subjectively have whatever is required in place to support the highest possible boost, but I really want to see how far I can push it (while remaining reasonably efficient for a Big 16g) since it hardly gets run hard.

Most of the answers that I see for a Big 16g are from a few years back since there are other turbos/preferences nowadays.

Any thoughts?

Thank you for your time.

 

[Splitpi]

>What is the max boost that can be run on 93 octane on a 16g if knock and A/F are in control?

The maximum amount of boost that does not create knock as read by mmcd logger. There is no definitive answer to this. You will need to up boost a little, see if you have knock. Decrease if you do or fiddle with the fuel.

 

[4gfun]

>What is the max boost that can be run on 93 octane on a 16g if knock and A/F are in control?

The maximum amount of boost that does not create knock as read by mmcd logger. There is no definitive answer to this. You will need to up boost a little, see if you have knock. Decrease if you do or fiddle with the fuel.

Thanks for your response. I have just created a new tuning thread in accordance with this type of question.

The issue I that I have read that I need to start off with as high a boost as the turbo will run efficiently, and I have also read your method. It seems to be 50/50. I am lost

To highlight what I posted in that thread without having you shuffle...this is what I believed to be the most accurate way of determining boost:

1.) Set the turbo's boost psi to where you want it.

2.) Turn the timing DOWN lower than you know it will go.

3.) Tune for A/F, EGT, or O2. (Yes I know that some are not as accurate as others).

4.) Once you have completed step 3, slowly start advancing timing untill you get knock nad then back it down 1* at a time untill there's little to none.

 

[dsmtalontsi95]

every car is different.

 

[FonZ454]

My car will spike to 22psi dropping to 19 psi. Almost no knock now (had to do a lot of tuning, back down the timing a good amount) but the car pulls cleanly and runs the time in my sig on 93 octane.

Never use boost as a number, tune the car to the most boost you can while being knock free... don't say "i want to run xx psi" because every car will be diferent and boost alone doesn't make power.

Also on a small 16g size turbo running that boost needs a good intercooler.

 

[4gfun]

My car will spike to 22psi dropping to 19 psi. Almost no knock now (had to do a lot of tuning, back down the timing a good amount) but the car pulls cleanly and runs the time in my sig on 93 octane.

Never use boost as a number, tune the car to the most boost you can while being knock free... don't say "i want to run xx psi" because every car will be diferent and boost alone doesn't make power.

Also on a small 16g size turbo running that boost needs a good intercooler.

How many psi were you running for that time in your sig? (I particularly like your trap speed).

I got what you are saying. I am just looking for a baseline of sorts. Just a rough idea.

Why did you mention a small 16g? Is that what you are running?

Thanks

 

[FonZ454]

How many psi were you running for that time in your sig? (I particularly like your trap speed).

I got what you are saying. I am just looking for a baseline of sorts. Just a rough idea.

Why did you mention a small 16g? Is that what you are running?

Thanks

I think that boost was probally the same. 22 dropping to 19. I've ran as high as 25psi spikes, but it still always drops back down. Never really increased trap. My highest trap speed was 113.97.... All on straight pump gas. Start at 20psi assuming you have all supporting mods and slowly increase it, assuming your car is not knocking and has safe AFR's.

And by that I meant "on any small, 16g like"... meaning small turbos tend to produce a lot of heat and proper intercooling is key.

 

[4gfun]

thanks

 

[winterftbl]

THe 16g turbo loses effiencency at about 25psi. So you really dont want to go higher than that, unless meth or water injection is used.

 

[talon187]

you didnt metion injectors? are you on stock? if so no more then running 14psi with a logger to make sure all is safe

 

[xtreme-elements]

you would want efficient boost.. you should run the boost that would give you the most power with no knock.. evo 3 16g with 550cc and proper mods and proper tune at 22-25 psi have been known for over 400 whp

 

[Black_Bullet]

Theres also other variables like what compression pistons are those JE's you have, and what cams do you have. ( You stated bigger cams but nothing specific.) As certain cams increase cylinder pressure enough to lower your boost thresh hold ( Such as the fpx series cams with the increased ramp rate.)
Also, if you have E85 avaible id say set your car up for that ( Like I want to. ) And get away with 25psi with 25-30 degs of ign timing adv knock free and be making gobs of hp and torque on the 16g.
On my evo3 on 93 pump I run 17deg timing with a 11./1 AFR with 20psi but in 3rd, 4th, and 5th gear I spike to 23psi and then it settles back down to 20. I just mainly need some cams for my set up, and its well capable enough to trap above 110 as is! If you use it right the 16g can offer a lot.

 

[4gfun]

Yes all stock injectors.

I don't know what kind of Cams are in this car or even the compression ratio on the JE pistons. My compression test makes me believe me that they are stock 7.8:1 compression ratio though. (Don't even ask why I came to such a conclusion ).

I can't even be sure that the car actually has this stuff because that is what the previous owner asserted.

Are you saying that if we get 10% E85 here at the pump to take that into consideration?

How and where would I get pure E85 if this is what you are thinking?

Thanks

 

[Black_Bullet]

Yes all stock injectors.

I don't know what kind of Cams are in this car or even the compression ratio on the JE pistons. My compression test makes me believe me that they are stock 7.8:1 compression ratio though. (Don't even ask why I came to such a conclusion ).

I can't even be sure that the car actually has this stuff because that is what the previous owner asserted.

Are you saying that if we get 10% E85 here at the pump to take that into consideration?

How and where would I get pure E85 if this is what you are thinking?

Thanks

Take off valve cover and maybe you can see something that shows its an aftermarket cam, even measuring the lobe might tell something, I dont know though because ive never purchased aftermarket cams...yet. As far as the compression test, 1g pistons shouldnt go over 160 ( unless theres carbon build up.) My 1g piston results give me 160,155,150,149...What were your results?
As far as the E85, check here National Ethanol Vehicle Coalition to check for availability in your area.
Id run this stuff like crazy if I had it in my area, its has much higher octane levels than regular 93 and is less prone to detonation.
As far as that 10% ethanol sticker at the pump has nothing to do with what im talking about just means they used 10% less ethanol for better gas milage I think. Im talking about running pure e85. Or you could always do meth injection to max out your 16g, whatever is cheaper and makes more sense for you to do.
Now seeing that you are on stock injectors, you shouldnt pass 15psi or you run high probability of leaning out. I run 850s on my evo3 set up.
FYI To run e85 you will need huge injectors and therefore will need more than a safc to compensate.

 

[FonZ454]

you would want efficient boost.. you should run the boost that would give you the most power with no knock.. evo 3 16g with 550cc and proper mods and proper tune at 22-25 psi have been known for over 400 whp

On race gas, bigger injectors and much more boost. I only know of a few 400+ whp 16gs. 350+ on race gas is a safer number to say. On an evo3 of course.

 

[Black_Bullet]

On race gas, bigger injectors and much more boost. I only know of a few 400+ whp 16gs. 350+ on race gas is a safer number to say. On an evo3 of course.

FonZ454 when you gonna throw cams on that thing and hit the track again ! Im pretty much at the same spot your at for 1/4 and hp and weight thats why im curious how your next moves going to look

 

[FonZ454]

FonZ454 when you gonna throw cams on that thing and hit the track again ! Im pretty much at the same spot your at for 1/4 and hp and weight thats why im curious how your next moves going to look

I got some BC 272's sitting right here, just ordered a larger FMIC core, and hopefully getting a 3" exhaust soon. Heh, next year should be fun. But being in New England, I have to wait till May to run again , so I'll have some down time. Car should be a bit quicker next year

 

[Supa Dexta]

First and foremost you really should find out exactly what you are running, it makes it easier from here on in to mod, what to match with it, and it's safer for tuning when you know what you're working with...

 

[4gfun]

Take off valve cover and maybe you can see something that shows its an aftermarket cam, even measuring the lobe might tell something, I dont know though because ive never purchased aftermarket cams...yet. As far as the compression test, 1g pistons shouldnt go over 160 ( unless theres carbon build up.) My 1g piston results give me 160,155,150,149...What were your results?
As far as the E85, check here National Ethanol Vehicle Coalition to check for availability in your area.
Id run this stuff like crazy if I had it in my area, its has much higher octane levels than regular 93 and is less prone to detonation.
As far as that 10% ethanol sticker at the pump has nothing to do with what im talking about just means they used 10% less ethanol for better gas milage I think. Im talking about running pure e85. Or you could always do meth injection to max out your 16g, whatever is cheaper and makes more sense for you to do.
Now seeing that you are on stock injectors, you shouldnt pass 15psi or you run high probability of leaning out. I run 850s on my evo3 set up.
FYI To run e85 you will need huge injectors and therefore will need more than a safc to compensate.

I will take off the valve cover when it's time to paint it again. My compression results were around 170, 152, 170, 170. (Yes I know about the 15 psi difference between cylinders). With my luck, the other cylinders are just carbon buildup. I'll just live with it until things get really tired. Yes, I checked that site right before you posted, but it turned out that there is only one place in my state where I can get it.

Good info on the 10% less ethanol.

 

[4gfun]

First and foremost you really should find out exactly what you are running, it makes it easier from here on in to mod, what to match with it, and it's safer for tuning when you know what you're working with...

True, but I don't want to tear things down too much to be sure if you know what I mean. No way for me to tell what alot of the mods really are without solid PROOF from the previous owner. At the same time, I'd probably be taking an equal risk assuming they are not on the car.

 

[4gfun]

Were those 400 hp 16g vehicles run on pump gas?

I just want to tune on pump and call it a day. The car will probably not see much time at the track if ever.

My days of street racing are pretty well done to.

I am getting to the age where I just want to know it is there loooool!!

 

[Black_Bullet]

I will take off the valve cover when it's time to paint it again. My compression results were around 170, 152, 170, 170. (Yes I know about the 15 psi difference between cylinders). With my luck, the other cylinders are just carbon buildup. I'll just live with it until things get really tired. Yes, I checked that site right before you posted, but it turned out that there is only one place in my state where I can get it.

Good info on the 10% less ethanol.

Well i think its safe to assume its not 1g pistons like youve said... UNLESS the head is shaved... Either way you know what compression you have, if you stay under 500whp you wont have to put forged internals anyways and the evo3 wont take you no were near 500whp even if you max it out so your ok. Just get something that you can really tune the balls off of the car and the compression wont matter... Theres guys running 9:5.1 compression with 20+ psi on pump gas... Tuning is key.

True, but I don't want to tear things down too much to be sure if you know what I mean. No way for me to tell what alot of the mods really are without solid PROOF from the previous owner. At the same time, I'd probably be taking an equal risk assuming they are not on the car.

Taking off the valve cover is all but like 14 screws holding it ontop. That should be no more than a 5 minute job and that way you can check the whole head out to see the condition of everything in there.

Were those 400 hp 16g vehicles run on pump gas?

I just want to tune on pump and call it a day. The car will probably not see much time at the track if ever.

My days of street racing are pretty well done to.

I am getting to the age where I just want to know it is there loooool!!

No way, 400whp on a 16g needs race gas. Compressor is too small, and the turbo is being taking out of its efficiency so there is enormous heat being built up in the intake tract, pump gas can not deal with that... Youd be very lucky and skilled to even extract 350whp out of a evo3 16g with only pump gas and it would be running on the ragged edge in my opinion. A well tuned pump gas 16g set up should bring you close to 330whp and with a properly set up car with at least 200-300lbs worth of weight reduction and extremely good awd launching and driving should give good back to back high 11 second passes trapping around 115-120. Pretty much were i am going to be once I get cams and throw more boost at it with a better tune.( I run 20psi spiking to 23 daily, Mods in profile.) I know what you mean with the racing part as my days with that stuff is over too, but its always nice to take it out to the track a couple times a yr and know your car is using its potiential. Get to that point first and then see if you want more.

 

[4gfun]

Well i think its safe to assume its not 1g pistons like youve said... UNLESS the head is shaved... Either way you know what compression you have, if you stay under 500whp you wont have to put forged internals anyways and the evo3 wont take you no were near 500whp even if you max it out so your ok. Just get something that you can really tune the balls off of the car and the compression wont matter... Theres guys running 9:5.1 compression with 20+ psi on pump gas... Tuning is key.



Taking off the valve cover is all but like 14 screws holding it ontop. That should be no more than a 5 minute job and that way you can check the whole head out to see the condition of everything in there.



No way, 400whp on a 16g needs race gas. Compressor is too small, and the turbo is being taking out of its efficiency so there is enormous heat being built up in the intake tract, pump gas can not deal with that... Youd be very lucky and skilled to even extract 350whp out of a evo3 16g with only pump gas and it would be running on the ragged edge in my opinion. A well tuned pump gas 16g set up should bring you close to 330whp and with a properly set up car with at least 200-300lbs worth of weight reduction and extremely good awd launching and driving should give good back to back high 11 second passes trapping around 115-120. Pretty much were i am going to be once I get cams and throw more boost at it with a better tune.( I run 20psi spiking to 23 daily, Mods in profile.) I know what you mean with the racing part as my days with that stuff is over too, but its always nice to take it out to the track a couple times a yr and know your car is using its potiential. Get to that point first and then see if you want more.

Very interesting. I figured I would just be the unlucky carbon guy as usual.... Your car sounds awesome. I will get there.

 

[talon187]

might want to do some checking the record for a big 16g is pretty close to 450 whp the car ran 10 somthing at the track on it. theres a thread on here wirh all the details but it is possible to make 400whp on a 16g

 

[Black_Bullet]

might want to do some checking the record for a big 16g is pretty close to 450 whp the car ran 10 somthing at the track on it. theres a thread on here wirh all the details but it is possible to make 400whp on a 16g

Might want to re read my post, i said your not making 400whp on a 16g with pump gas.
The guys making 400+ are on race gasf... Sorry but the average person wont see that type of power on their 16g not to sound pessimistic.