Safe, max psi on a 16G???

[91TSi]

Assuming I have supporting fuel mods, UICP, S-AFC, etc. Just want to know what psi you can run because I allways read posts related to 16G's and the people are only talking about 15psi??? Im pretty new to the whole DSM scene but correct me if Im wrong... cant you get 15psi out of a 14B??? If so is there a big diffrence between 15psi on the 16G and the 14B??? Maybe thats where Im getting confused. Thanks for any imput in advance guys.



Robert

 

[91gsx]

my 16g pulls a lot harder at 13 psi (yes i said 13) than my 14b did at 16-17psi. i have read that the 16g performs best around 20psi. a friend of mine who ran a 16g got his best et's around 20psi.

 

[nothing stock]

I ran 20psi ever day on my 16g. 12.4 @ 107 on 91 octane.
You did say you had all the supporting mods. Hopefully you do, but I'm betting you don't.

 

[Rafael Barbosa]

dude 15 psi is 15 psi ... BUT there are many things that add to this ummm boost lag or boost creep ... Lag is the time that it take a turbo ti start spooling like a t25 on a 95 + usualy spools up at around 2200 rpms but lets say that you put a 16 G on that same car it will prob start to spool around 3500 rpms .... BUT when that red needle hits that 3500 rmps hold on cause your car will turn into a bat out of hell ... also the other diffenceis that the smaller stock turbos cant hold out 15 psi as long a a 16g could

 

[Rafael Barbosa]

o yea one more thing it also depends on turbo your using lets say you get a Hans race craft turbo ok ( i no im not sapose to nag or put down other companies but come one a full size 20g turbo for $1300 o come on that insane a frankestein JR would eat that turbo ) so yea a 16 turbo you can have running 19 to 20 psi all day as long as you have those mods listed

 

[candela]

, you obviously have never ridden in a 16g equipped car huh? Max psi I run is 23psi on the big16g in my car. Its all about tuning, timing fuel trims and such. You may be able to run more safely or less safely it all depends on your mods and tuning. Dont worry my big16g hits full boosy (18psi) at 3200 rpm. And 15psi is 15psi but not how your motor sees it. Simply put, dodnt want to start an arguement, but 15psi on a t25 will not feel like 15 psi on my 16g period. Yes boost is boost but its all about temps and inefficiency here, which is how your mttor sees it.

 

[CBgst]

Originally posted by candela
, you obviously have never ridden in a 16g equipped car huh? Max psi I run is 23psi on the big16g in my car. Its all about tuning, timing fuel trims and such. You may be able to run more safely or less safely it all depends on your mods and tuning. Dont worry my big16g hits full boosy (18psi) at 3200 rpm. And 15psi is 15psi but not how your motor sees it. Simply put, dodnt want to start an arguement, but 15psi on a t25 will not feel like 15 psi on my 16g period. Yes boost is boost but its all about temps and inefficiency here, which is how your mttor sees it.

He's right. My big28 pulls WAY harder than t-25 did at the same boost. It's all about efficency. The more efficent the turbo at 15psi the harder it pulls.

 

[GRNDSM]

I have ran 25psi on a small 16G when it did 12.05@113 (on race gas). But not every 16G will be able to support such high boost in every case. You can run into a situation where boost starts to drop off at higher RPMs. Something similar to what T25, but at higher RPMs, so people might set it to 25psi but it drops down to 20psi (or so).

I would start with 20psi and go up with 1psi increments to see how far it will take it. Your knock will also be a huge factor. But there is a point beyond which it does not make sense to increase the boost and it will vary greatly from car to car.

Leon
RR

 

[InferiorWang]

Originally posted by Rafael Barbosa
dude 15 psi is 15 psi ...

who told you that? 15 psi of hot air and 15 psi of cool air are two different things. With a larger turbo, that 15 psi of air doesnt heat up as much, there for it is cooler and denser. Denser means more o2 which means more fuel can be burnt and you get the idea of where im going with this.

 

[LaserRST]

Another thing to add to all this GOOD information is that there is a difference between spooling up and spooling hard. Sure a stock 14b can spool up to 20 psi, but its design wont hold 20 psi. This is all about design. Look at a 14b impeller design vs a 16g impeller design. Its wings are all linear meaning the space between em is the same. At 20 psi it is working against itself to MAINTAIN boost. What I mean by this is that it takes the same amount of force to go both ways on the impeller if that makes sense. While the 16g, 25t, some smaller 14 series, and any good PERFORMANCE turbos has a staggard impeller design which is more efficient because boost created by the turbine is held with its impeller design and not working as hard to MAINTAIN boost. This does though create more heat. Though dont git a 14b wrong it will spool quicker than a 16g, but has a smaller peak efficiency range. 15 psi IS 15 psi, but what does it take to put that in the engine, when one cylinder takes its share of volume, how quick or efficient is that turbo to replenish the same amount of air, compressed. To answer your initial question, your peak psi depends soley on your supporiting mods. The stock engine is designed for 10-12 psi round about there. This is the safest, most economical, and marketable performance figure the manufacturer has figured thats all the car needed to be a hot seller. And it is!! Whatever potential this car has, they left alone, which is a whole lot!! Feul management is the biggest issue for performance modification any car will have. This is right up there with flow or CFM, only because feul management will determine wether the car runs great or the car blows up. Flow is the next most important issue. Sure the guy ran his car at 26 psi, but still didnt quite break 12 sec 1/4 miles, and is right up there with the guy thats running 21psi,why? He has tapped what he can shove into the engine. He increases the CFM in the valves, exhaust, intake, TB, inter cooler, turbo, intake, and does the right mods to push his redline up 500rpm, while running the same 26 psi, and boom...hes now running high 10s. Hope this is insightful and fills your head with alot more questions...

 

[GRNDSM]

I am playing around with a 14b right now. It really does not matter what I set the boost to. It drops to 17psi by 7000 rpm. I just had to re-adjust my driving style and shift sooner than my usual 8000-8400prms .

Last Wed. I did [email protected] running 20-17psi on a 14b. Now, I just need a day of good traction to brake it into 11's .

Leon
RR

 

[Violater101]

I wouldn't run more than 18 to 19psi on pump gas. Like everyone has been saying, its all about your egt's,timing & a/f etc. Noone can tell you what is truely safe. Every car is different, but with the supporting mods and proper tune, you should be having fun around 18psi.

 

[GreenGVR4]

I dont know what kinds of mods you guys have , or if its just the altitude up here in denver, but i also have a 91 GSX with very few mods, full 2.5in 16g, k&n, and Clutch and i am running between 14.0 and 14.2 at 17 pounds of boost and 114 octane gas, with like 1.9 60' and .700 r/t. my car must just be slow or something, because you are talking about low 12s with a 14b, then again i have never seen anyone run in the 13s at this altitude with a 14b. i have a friend that has a 20g on his GVR4 and runs 13.1 @ 20psi

 

[BlueShark]

GreenGVR4, What was your trap speed?

 

[GreenGVR4]

94-96mph

 

[candela]

If all you have is the 16g, k/n 2.5" exhaust then no wonder. Your driving seems ok with your 60ft and 1/8th but your not making any power. I trap 109mph with my 16g@ 20psi. Youd need some more fuel mods, uip, lip downpiped and ported 02 and then possibly get rid of the stock smic and then you could be running great numbers on your 16g. The altitude sucks, but not that much

 

[GreenGVR4]

forgot to mention, i do have ported 2g exaust manifold, and 02 housing