EGT Control

strok-n · Aug 26, 2015

ja_cain said:
See my original post a couple pages back. Basically what I was saying, but I don't have experience with this type of setup. Sometimes I feel like I'm just raising the noise floor with my comments. Lol!

He did say that he felt like the 71 was building boost fairly early somewhere above. It would be nice if we could get a data log of the primary and secondary boost relative to rpm so we can figure out the pressure ratios. I know that isn't possible in this case, but it would be nice. Maybe a video displaying the boost/egt gauges and rpm would be possible.

I will be gone for a week but as soon as I get back I will get a video. I was able to take it out again last night and mainly watched boost from the 591. At 10lbs overall I am at 5lbs on the 91. I can achieve this at 2500RPM using about half throttle.

crcrawford87 · Aug 26, 2015

In pic 3 your exhaust clamp is not situated over the v band flange- not sure if this pic was snapped mid repair or if it's still like that?

strok-n · Sep 2, 2015

crcrawford87 said:
In pic 3 your exhaust clamp is not situated over the v band flange- not sure if this pic was snapped mid repair or if it's still like that?

hey that pic was taken mid repair. It is back on now.

strok-n · Sep 2, 2015

Wasnt able to get a good video, but was able to get some data. Cruising temps(EGT's) seem to range from 750-950. Spooling up at the line i will hit 1200-1300. And 1/8 mile WOT I will see 1800. Boost cruising will be 5-10lbs. I usually launch at 20-25lbs, and and the end of the 1/8 i am seeing 65-75lbs Any input on these numbers?

TyCorr · Sep 3, 2015

Hp too large....low pressure almost too small

With 250/200s it should be easy to size the atmo for no gate. And the gate from the hp should be tuned to keep it in the map at max fuel.

Also, id never have deviated from a stockish hp and left any of that mess in the valley. All that plumbing increaes lag, reduces efficiency(heat).

With that little fuel you either arent using the air or fuel. Thats all it can be.

Dieselboy answered this question.

There are three compound setups already done over the years two of which used a 38r and were NOT gated. With waaaaay more fuel on tap.

Those chargers, if they are working would clean a 250/200 ALL DAY LONG.

Your secondary is totally killing your buzz. Or double your fuel.

Gearhead · Sep 3, 2015

Something to remember about compounds that some people overlook is this:
A non-spinning turbine wheel acts like a HUGE restriction. In this case your high pressure turbo is having trouble spooling because it doesn't see a good pressure DIFFERENTIAL across it's turbine because there is a blockage at the atmosphere turbine.

strok-n · Sep 3, 2015

******** said:
Something to remember about compounds that some people overlook is this:
A non-spinning turbine wheel acts like a HUGE restriction. In this case your high pressure turbo is having trouble spooling because it doesn't see a good pressure DIFFERENTIAL across it's turbine because there is a blockage at the atmosphere turbine.

Alright I understand this, so would it be beneficial to drop the High pressure to something smaller?

Gearhead · Sep 3, 2015

Sounds like that would be the easiest.

psduser1 · Sep 3, 2015

strok-n said:
Alright I understand this, so would it be beneficial to drop the High pressure to something smaller?

Maybe a tighter housing, with a bigger gate, on the hp turbo? Don't know what available for a 371.

NyCowboy87 · Sep 3, 2015

Fwiw I ran 400/200's with a 66/76 19cm hx55 and a 86mm s4t (same turbine as a s500) with a 1.15 housing and in a hot street tune (450-500hp) you could not get it to over 1150* with tunes from swamps. It was never live tuned and would run 65-70psi with NO gates. In a all out tune it would touch 1400* in a 1/4 and run 95-100psi. Drive pressure stayed 1:1 to 85psi and then would slowly climb but not bad at all.

If I were you I'd go down to a 64mm secondary with the large 74mm turbine and step down to a generic s480 as an atmosphere if you plan on staying with the small injectors. That s371 has no where near enough turbine to drive the compressor especially when it's being slapped in the face with the air from the 591.

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lincolnlocker · Sep 3, 2015

have you tried running it with the gates locked closed? i wouldnt think you would really need gates if tuning was right like nycowboy did with his..

live life full throttle

TyCorr · Sep 3, 2015

lincolnlocker said:
have you tried running it with the gates locked closed? i wouldnt think you would really need gates if tuning was right like nycowboy did with his..

live life full throttle

I personally don't think there is enough energy in that injector choice to fuel very hard.

strok-n · Sep 3, 2015

NyCowboy87 said:
Fwiw I ran 400/200's with a 66/76 19cm hx55 and a 86mm s4t (same turbine as a s500) with a 1.15 housing and in a hot street tune (450-500hp) you could not get it to over 1150* with tunes from swamps. It was never live tuned and would run 65-70psi with NO gates. In a all out tune it would touch 1400* in a 1/4 and run 95-100psi. Drive pressure stayed 1:1 to 85psi and then would slowly climb but not bad at all.

If I were you I'd go down to a 64mm secondary with the large 74mm turbine and step down to a generic s480 as an atmosphere if you plan on staying with the small injectors. That s371 has no where near enough turbine to drive the compressor especially when it's being slapped in the face with the air from the 591.

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Alright I think I will try a smaller secondary. I had planned to bump up the injectors but I still drive this truck on the street every once in a while and don't want to be a smoke show.

NyCowboy87 · Sep 3, 2015

Take a look at the video, I am in no way trying to talk up my setup but it flat out worked. No smoke or blackouts in the street tunes and that is with injectors dam near twice the size of yours and smaller chargers. I'm not knocking you or saying your dumb, but I truly believe your charger selection is way wrong. I love to see people with bad ass 7.3's and am willing to help most anyone, so if I can help ya I will. You can pm me if you would like.

http://youtu.be/L2I8p2kgXcE
http://youtu.be/HZTZW-xiBjs
http://youtu.be/jN-QPLVialg

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strok-n · Sep 3, 2015

NyCowboy87 said:
Take a look at the video, I am in no way trying to talk up my setup but it flat out worked. No smoke or blackouts in the street tunes and that is with injectors dam near twice the size of yours and smaller chargers. I'm not knocking you or saying your dumb, but I truly believe your charger selection is way wrong. I love to see people with bad ass 7.3's and am willing to help most anyone, so if I can help ya I will. You can pm me if you would like.

http://youtu.be/L2I8p2kgXcE
http://youtu.be/HZTZW-xiBjs
http://youtu.be/jN-QPLVialg

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thanks for the videos. I can always use the help haha. Do you think I could run an S369 for the secondary and be good.

NyCowboy87 · Sep 3, 2015

Doubt it. Might be better but probably not much. Quite honestly I don't believe a s300 frame charger has enough turbine to be the best choice for a secondary. Maybe once you get down around a 64 compressor it will start to work better for ya. I've found that you can run a really large turbine side on these engines without sacrificing spool up and it makes an all around better more efficient setup. You need a large turbine to drive the compressor (of the secondary) efficiently.

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ja_cain · Sep 3, 2015

NyCowboy87 said:
Doubt it. Might be better but probably not much. Quite honestly I don't believe a s300 frame charger has enough turbine to be the best choice for a secondary. Maybe once you get down around a 64 compressor it will start to work better for ya. I've found that you can run a really large turbine side on these engines without sacrificing spool up and it makes an all around better more efficient setup. You need a large turbine to drive the compressor (of the secondary) efficiently.

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This is really good info. I've been thinking about the new s364 with the larger turbine instead of the BASB since it would be cheaper. Then if I ever wanted to go to compounds I should be good to go with the right atmo. It makes sense that you need more turbine on the secondary since the primary seems to be developing boost ok according to the op's info. To Ty's credit, it would be interesting to see what bigger nozzles (more energy) would do with this setup.

strok-n · Sep 3, 2015

NyCowboy87 said:
Doubt it. Might be better but probably not much. Quite honestly I don't believe a s300 frame charger has enough turbine to be the best choice for a secondary. Maybe once you get down around a 64 compressor it will start to work better for ya. I've found that you can run a really large turbine side on these engines without sacrificing spool up and it makes an all around better more efficient setup. You need a large turbine to drive the compressor (of the secondary) efficiently.

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alright so do you think an s468 turbo would be better, since it has a larger turbine wheel.

thanks

uncool · Sep 3, 2015

Would you be interested in trying more fuel?

I can send you my 3ish/200's. They made a touch over 675 on a single 72/76 x 83 S400.

They are fresh, in the box ready to go.

Marc