Clipping VS Non-Clipping (Big16G)

[kingearl]

Ok, say you have all the fuel and air flow needed for the top performance of a ported Big 16G turbo. What would be the differance if it were clipped or not........... on race gas?

From what I understand, non-clipped should be around 23psi, clipped 26psi. Are my numbers off? What other problems beside lag might be assosiated with clipping?

Thanks

 

[97GSTURBO]

Just Lag as far as I know.

 

[candela]

IMO clipping is not worth a damn on a 16g....

 

[kingearl]

Why? I am trying to decide on which to go with. If you have reasons, please state them.

 

[Enigma_Man]

Clipping has always sounded like a bad idea to me. I don't have any real experience, btw, so this is all speculation, but here's my thoughts:

Clipping is done to allow more exhaust gases to flow through the turbo at the expense of more lag. The clipping makes the exhaust turbine blades smaller, and therefore not interfere with the exhaust flow so much.

It seems to me that you wouldn't ever want to do this, because you _want_ the turbo to be "in the way" of the exhaust flow, that's what makes it spin, and if it's in the way too much IE overboosting, that's the job of the wastegate to not allow overboosting due to higher flow of exhaust.

See what I mean? Clipping just sounds like the wrong fix to the problem... As long as the wastegate can flow enough, why would you want to make the exhaust turbine less efficient?

-Jesse

 

[Slowboy]

Clipping in most cases is a bad idea.... It kills the efficiency of the turbine wheel in order to let more exhaust gas pas through... Making it act like a larger, more efficient wheel.

Spool will suffer, but you will gain ever so slightly on the top end. I would not be real concerned about clipping any 16g....

why would you want to make the exhaust turbine less efficient?

Good call Jesse.

Regards,

Mike Huml

 

[mrfloppy]

Originally posted by kingearl
From what I understand, non-clipped should be around 23psi, clipped 26psi. Are my numbers off? What other problems beside lag might be assosiated with clipping?

Thanks

even if your #'s are right it would only help you on the top end level... what good is 3 PSI at the cost of your overall spooling time (lower range as well as the mid-range) .

Ask yourself, how long will those 3 PSI hold and how effective will it be in that time?

 

[DCJ98GST]

The FP Big 28 has a clipped turbine wheel.

 

[Black_90TSI]

Clipping will help you out on the top end and that is what you want so I recomend it. My big16 is clipped and seems to do fine high psi.

 

[kingearl]

what is the max of a ported, non-clipped then? Whats the highest anyone has run on these. I am going to order one today and still need to decide which.

If the clipping were free, would you have it done?

 

[Slowboy]

If you paid me double to clip it, I would still talk you out of it. We have run 12.0's on a stock motor car and a small ported 16g..... what else can you ask for?

Regards,

Mike Huml

 

[RACER-X]

yeah mike, but even us n/a guys know your rep. in the turbo world ... my question to you is how do you get a small 16g to run 12.00's ?.. and on stock motor at that. what's your secret?

 

[Bohrn]

Listen to Mr Huml.

Also, don't let the 16g fool ya. There are guys in the 12s on 14bs, so the 16g should be no prob at all.

 

[meangreengst]

put a 16g on a stock motor and connect that to a tranny,4 wheels a stering wheel and a seat,thats it!, you'll run 12s..........mabey 11s..!! j/k

 

[Slowboy]

my question to you is how do you get a small 16g to run 12.00's ?.. and on stock motor at that. what's your secret?

Here is the formula:

small 16g, ported
550 cc injectors
afc
stock maf
small spearco/ griffen IC with piping
3" turbo back exhaust
3100 lbs with driver
Walbro 190 pump
ported 1st gen manifold
ported o2 housing
stock ecu

I have my little brother drive the car also... and he is somewhat better than I About 22 psi, a little turbo blue, strive for less than 7 counts of knock, and 21-22 degrees of timing top of fourth gear..... EGT's were about 880 C coming through the traps..

The 16g is the most under rated turbo on the planet when set up right on a car..... This turbo made about 100 total passes on the car that year, and MPH was always 114-116....

My brothers 91 tsi, runs 12.8's at 106 without even a fuel pump...... It has

small 16g ported
ported 1g manifold
custom os housing with dump tube
upper IC pipes
modded side mount IC
2.5" exhaust

He runs 16-17 psi... little to no knock and runs high 12's fairly easy in a car that weighs 3300 lbs with him in it.

Regards,

Mike Huml

 

[RACER-X]

damn, now those are some good numbers.

 

[candela]

Yes the reason I said I wouldnt do it is just because I cant imagine anything to be gained from a 16g and clipping. I dont even think that if it were clipped it would help top end.... My Ported Big16g holds 22psi to 7 grand easily. How would you know if it will help? The only way is to max out your currecnt 16g and be running consistently, then do nothing else but clip the wheel and see what it will get you


Austin

 

[LaserRST]

Clipping allows the turbine to spin faster with less backpressure. They do this for all the drag applications. If you want the light to light vs a high revving good 1/4 mile... well is up to you... clipped to me is like going from stage 1 to stage 2 turbine on a T3. More flow.. my 0.02

 

[Slowboy]

If you want more flow, get a bigger, more efficient turbine wheel

Regards,

Mike Huml

 

[lithium]

Clipping also creates a higher intake charge temp. It requires more exhaust gasses to spool the turbo up to the same boost level.

 

[Bohrn]

Does a GT-10 come to mind Mike?

When I can afford it, Im gonna grab me one of your ported small 16g's with the bigger wastegate. I hate boost creep.

 

[RACER-X]

gt-10... why stop there go gt-12.

 

[Slowboy]

Does a GT-10 come to mind Mike?

Well.... maybe but I will try to stick on topic

I will have your turbo when you are ready! I hate boost creep also, the WG mod is a great way to go.... I should make it standard!

Regards,

Mike Huml

 

[Bohrn]

yea, that would help entice a guy who has to spend canadian $$$ on a new turbo

oh, and back on topic, I wouldnt clip unless I was making a 1/4mile only car.