Rear Mount Twin Turbo
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Joined: Jul 2009
Posts: 83
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From: Florida
We would have to get the exhaust housing up to around 400F before it would be consistent and make big power on the few STSs kits that I tuned. That means we had to do 4-5 pulls just to get one power run. This causes a lot of heat soak on the engine and I believe this is why they put down smaller numbers with the exact same turbo set up as a front mount setup. This and the boost per gear at the track (1/4 mile) was very weak. We were only seeing 2 to 3 pounds in 1st, 4 or so in 2nd, 6 in 3rd, and 8 in 4th down the quarter mile. Im sure it has a lot to do with the amount of heat at the turbo.
i understand lag would be logner due to the physical aspect of the gas having to travel farther. but im going to be using relativly small turbos so lag shouldn't be too out of control. My biggest question is with all the DIY people on this site no one has attempted this? I don't want to be having to fight a uphill battle to get this turbo kit to work efficently.
You will generally get bit cost wise on fittings, couplers, clamps and piping that are often hard to account for.
What you want to do is more than reasonable and achieveable. However, your choice in turbo size and A/R will be even more crucial for a rear mount TT.
We would have to get the exhaust housing up to around 400F before it would be consistent and make big power on the few STSs kits that I tuned. That means we had to do 4-5 pulls just to get one power run. This causes a lot of heat soak on the engine and I believe this is why they put down smaller numbers with the exact same turbo set up as a front mount setup. This and the boost per gear at the track (1/4 mile) was very weak. We were only seeing 2 to 3 pounds in 1st, 4 or so in 2nd, 6 in 3rd, and 8 in 4th down the quarter mile. Im sure it has a lot to do with the amount of heat at the turbo.
Z Car Garage (www.zcargarage) put together a single turbo car and I believe they experienced the same situation. Lots of piping, not much boost, so not much power.
bottom line no power, no go imo. The corvettes love the twin rear mount set up is that because of added displacemtn involves more heat meaning by the time they hit the turbos the amount of free energy is still enough to produce effcient power?
Just a quick 30 minute rendering as an idea:
Note that the turbos would not be symetrical in real life and the piping would have different bends in it in order to clear the driveshaft, fuel tank, swaybar and differential. Also please not that the foundry that made the compressor side of the above turbos does not know what they are doing
Note that the turbos would not be symetrical in real life and the piping would have different bends in it in order to clear the driveshaft, fuel tank, swaybar and differential. Also please not that the foundry that made the compressor side of the above turbos does not know what they are doing
you'll definitely make power. a fully wrapped 2" exhaust and smallish turbos and it would probably be pretty responsive on the street. After the car heated up, bigger turbos probably wouldnt be that bad either.
All we can do is guess. I say try it. Fab'ing the piping wouldnt be too difficult as any exhaust shop could do it fairly quickly.
All we can do is guess. I say try it. Fab'ing the piping wouldnt be too difficult as any exhaust shop could do it fairly quickly.
We would have to get the exhaust housing up to around 400F before it would be consistent and make big power on the few STSs kits that I tuned. That means we had to do 4-5 pulls just to get one power run. This causes a lot of heat soak on the engine and I believe this is why they put down smaller numbers with the exact same turbo set up as a front mount setup. This and the boost per gear at the track (1/4 mile) was very weak. We were only seeing 2 to 3 pounds in 1st, 4 or so in 2nd, 6 in 3rd, and 8 in 4th down the quarter mile. Im sure it has a lot to do with the amount of heat at the turbo.
We would have to get the exhaust housing up to around 400F before it would be consistent and make big power on the few STSs kits that I tuned. That means we had to do 4-5 pulls just to get one power run. This causes a lot of heat soak on the engine and I believe this is why they put down smaller numbers with the exact same turbo set up as a front mount setup. This and the boost per gear at the track (1/4 mile) was very weak. We were only seeing 2 to 3 pounds in 1st, 4 or so in 2nd, 6 in 3rd, and 8 in 4th down the quarter mile. Im sure it has a lot to do with the amount of heat at the turbo.
like this baby
quamen your model would combine the downpipes creating a little more back pressure than the free flowing pipes of the other option. with the slight inscrease in back preasure would spool times increase?
Last edited by athensgls; Aug 11, 2009 at 12:32 PM. Reason: pic
We would have to get the exhaust housing up to around 400F before it would be consistent and make big power on the few STSs kits that I tuned. That means we had to do 4-5 pulls just to get one power run. This causes a lot of heat soak on the engine and I believe this is why they put down smaller numbers with the exact same turbo set up as a front mount setup. This and the boost per gear at the track (1/4 mile) was very weak. We were only seeing 2 to 3 pounds in 1st, 4 or so in 2nd, 6 in 3rd, and 8 in 4th down the quarter mile. Im sure it has a lot to do with the amount of heat at the turbo.
I dont know about 4psi in second gear. I have a crappy Utec BCS and still hit 6+psi on 1st. I think I'll hit full boost on 1st and definitely 8psi on second with a good EBC.
Ran my STS about 20 times already on a quarter mile and here is one of my logs.. I'm set for 8psi by the way.
Edit: I also have the AIT logs so you can see I started at 19C and end up 35C after the pull so AIT is not crazy hot and this was my 6th run of the night.
Code:
[TSMP][RPM][PSIG][MAF][TPS][LOD][KN][SIG][IDC%][IGN][VOEF][BMV][MMV][WBO2][AIT][CLT] 1st Gear 000.40 4522 -11.0 2.1 0 0 0 34.3 7.7 ECU 100 000 1.6 12.07 019 085 000.60 3749 -10.5 1.9 2 0 0 32.2 4.5 ECU 100 000 1.5 15.26 020 086 000.80 3373 -8.5 2.2 41 0 0 41.3 44.9 ECU 100 000 3.4 21.80 018 085 001.00 3844 -0.4 3.7 98 10 0 29.1 36.2 21.0 +5.0 000 3.7 21.51 019 085 001.20 3958 +0.6 3.9 98 10 0 28.1 34.9 21.0 +5.0 000 3.6 15.51 018 085 001.41 4162 +0.7 4.2 100 10 0 28.0 41.0 17.6 +5.0 000 4.0 12.97 017 085 001.60 4501 +1.4 4.3 100 20 0 23.9 47.5 19.0 +5.0 000 4.2 13.21 019 085 001.80 4954 +2.3 4.5 99 30 0 20.9 62.3 18.0 +5.0 000 4.4 13.29 019 085 002.00 5423 +4.0 4.9 99 50 0 22.8 79.7 17.7 +5.0 000 4.6 12.82 019 085 002.20 5911 +6.1 4.9 99 60 0 25.0 90.5 18.8 +5.0 000 4.6 12.27 020 085 002.41 6426 +6.6 5.0 98 40 0 26.8 98.8 17.9 +5.0 000 4.5 11.74 021 086 2nd Gear 002.60 6640 -6.7 2.7 0 0 0 22.6 64.1 19.0 100 000 2.0 11.57 021 086 002.80 6440 -3.6 2.5 100 10 0 34.1 8.4 21.3 +3.0 000 4.4 12.48 021 085 003.01 5927 +2.6 4.7 100 40 0 13.3 59.6 17.8 +3.0 000 4.6 13.28 020 085 003.20 5450 +5.7 4.9 100 70 0 22.2 69.6 14.5 +3.0 000 4.6 12.73 022 085 003.40 5271 +7.0 5.0 100 70 0 07.9 82.9 15.2 +3.0 000 4.6 12.10 020 085 003.59 5326 +7.2 5.0 100 70 0 15.0 87.4 15.6 +3.0 000 4.6 11.97 022 085 003.80 5524 +6.9 5.0 100 70 0 15.0 88.5 15.9 +3.0 000 4.6 11.95 022 085 004.00 5770 +6.9 5.0 100 70 0 23.9 89.2 16.8 +3.0 000 4.6 11.91 023 085 004.20 6025 +6.9 5.0 100 70 0 23.8 90.1 17.2 +3.0 000 4.6 11.85 024 085 004.40 6269 +6.9 5.0 100 70 0 24.9 91.7 17.0 +3.0 000 4.6 11.79 024 085 004.60 6514 +7.1 5.0 100 70 0 24.8 93.3 17.5 +3.0 000 4.6 11.75 025 085 004.80 6950 +3.0 5.0 19 10 0 25.7 0.0 ECU +3.0 000 2.2 12.20 026 086 3rd Gear 005.00 7060 -6.6 3.5 99 30 0 45.9 47.1 19.1 +3.0 000 4.6 13.29 025 085 005.20 6095 +5.0 4.7 100 60 0 13.1 66.5 16.1 +3.0 000 4.4 13.26 025 085 005.40 5367 +7.1 4.9 100 80 0 16.1 80.9 07.7 +3.0 000 4.6 12.06 026 086 005.60 5242 +8.5 4.9 100 90 0 20.0 86.7 12.3 +3.0 000 4.6 11.51 025 085 005.80 5253 +8.2 5.0 100 80 0 19.4 87.3 13.4 +3.0 000 4.6 11.55 026 086 006.00 5299 +7.5 5.0 100 80 0 16.0 87.6 14.9 +3.0 000 4.6 11.50 025 086 006.20 5439 +7.0 5.0 100 70 0 20.9 87.1 15.4 +3.0 000 4.6 11.43 026 086 006.40 5561 +7.1 5.0 100 70 0 21.0 88.4 15.4 +3.0 000 4.6 11.48 026 086 006.60 5693 +7.2 5.0 100 80 0 22.1 89.1 15.2 +3.0 000 4.6 11.52 028 086 006.80 5827 +7.2 5.0 100 70 0 21.8 90.1 15.5 +3.0 000 4.6 11.52 026 086 007.00 5961 +7.3 5.0 100 70 0 22.8 90.8 16.1 +3.0 000 4.6 11.53 027 086 007.20 6088 +7.3 5.0 100 70 0 22.8 91.6 16.1 +3.0 000 4.6 11.51 027 086 007.40 6213 +7.2 5.0 100 70 0 23.7 92.3 16.1 +3.0 000 4.6 11.47 028 086 007.60 6333 +7.1 5.0 100 70 0 23.7 93.8 16.1 +3.0 000 4.6 11.44 028 086 007.80 6443 +7.5 5.0 100 70 0 23.9 93.9 16.5 +3.0 000 4.6 11.43 028 086 008.00 6548 +7.6 5.0 100 70 0 23.7 94.0 16.7 +3.0 000 4.6 11.46 029 084 008.20 6666 +7.3 5.0 100 70 0 24.9 95.4 16.9 +3.0 000 4.6 11.49 030 086 008.41 6779 +7.3 5.0 100 70 0 25.8 96.6 17.3 +3.0 000 4.6 11.43 030 086 008.59 6877 +7.1 5.0 100 70 0 25.8 97.1 17.0 +3.0 000 4.6 11.31 031 087 4th gear 008.80 7390 -5.2 3.1 1 0 1 13.6 72.0 18.5 +3.0 000 2.8 11.84 031 086 008.99 6821 +0.7 4.4 100 40 0 38.0 42.8 16.0 +1.0 000 4.5 12.73 030 086 009.20 6091 +5.8 4.8 100 70 0 12.0 80.2 15.9 +3.0 000 4.6 12.51 030 086 009.40 5756 +8.4 5.0 100 90 0 15.1 91.9 13.3 +3.0 000 4.6 11.74 030 086 009.59 5723 +8.8 5.0 100 90 0 19.4 98.0 13.0 +3.0 000 4.6 11.48 031 088 009.80 5697 +8.2 5.0 100 80 0 20.9 93.6 13.9 +1.0 000 4.6 11.30 031 086 009.99 5738 +7.9 5.0 100 80 0 20.8 91.5 14.8 +1.0 000 4.6 11.21 031 087 010.20 5820 +7.6 5.0 100 80 0 22.0 88.8 15.1 +1.0 000 4.6 11.30 031 086 010.40 5893 +7.5 5.0 100 80 0 21.7 89.0 15.5 +1.0 000 4.6 11.43 032 086 010.59 5964 +7.6 5.0 100 80 0 22.9 89.6 15.6 +1.0 000 4.6 11.53 032 086 010.80 6030 +7.7 5.0 100 80 0 22.7 89.7 15.9 +1.0 000 4.6 11.55 032 086 011.00 6099 +7.8 5.0 100 80 0 22.8 90.6 15.9 +1.0 000 4.6 11.50 032 086 011.20 6165 +7.7 5.0 100 80 0 22.7 90.7 15.9 +1.0 000 4.6 11.46 032 086 011.40 6222 +7.9 5.0 100 80 0 23.0 91.8 09.3 +1.0 000 4.6 11.41 032 086 011.60 6297 +7.8 5.0 100 80 0 23.9 92.8 15.2 +1.0 000 4.6 11.39 032 086 011.80 6375 +8.0 5.0 100 80 0 23.7 93.0 15.4 +1.0 000 4.6 11.44 032 086 012.00 6437 +7.9 5.0 100 80 0 24.0 93.7 15.6 +1.0 000 4.6 11.43 032 086 012.20 6496 +7.8 5.0 100 80 0 23.9 94.2 15.7 +1.0 000 4.6 11.37 033 086 012.40 6550 +7.8 5.0 100 80 0 24.0 93.9 15.9 +1.0 000 4.6 11.36 033 086 012.60 6615 +8.0 5.0 100 80 0 23.7 93.8 16.1 +1.0 000 4.6 11.35 033 086 012.80 6665 +7.7 5.0 100 80 0 23.7 94.9 16.0 +1.0 000 4.6 11.36 034 087 013.00 6720 +7.7 5.0 100 80 0 24.9 95.3 15.9 +1.0 000 4.6 11.39 035 087 013.20 6792 +7.6 5.0 100 80 0 25.9 95.5 16.0 +1.0 000 4.6 11.41 035 087 013.40 6850 +7.8 5.0 100 80 0 25.9 96.5 16.0 +1.0 000 4.6 11.46 035 087 013.60 6899 +7.6 5.0 82 10 0 25.8 97.1 15.7 +1.0 000 3.5 11.55 035 087 013.80 6626 -8.0 2.8 2 0 0 33.8 13.0 18.0 100 000 2.0 11.47 036 088 014.00 6127 -11.6 1.9 1 0 0 33.0 6.2 18.0 100 000 1.7 12.08 035 088 014.20 5500 -11.9 1.8 2 0 0 25.1 5.6 18.0 100 000 1.5 16.53 035 088
Last edited by athenG; Aug 11, 2009 at 12:52 PM.
Then buy a kit. Custom kits are not a waste of time IMO. However, they are not as easy as face value and they are generally not cheaper than a bolt on kit. Especially a custom twin turbo.
You will generally get bit cost wise on fittings, couplers, clamps and piping that are often hard to account for.
What you want to do is more than reasonable and achieveable. However, your choice in turbo size and A/R will be even more crucial for a rear mount TT.
You will generally get bit cost wise on fittings, couplers, clamps and piping that are often hard to account for.
What you want to do is more than reasonable and achieveable. However, your choice in turbo size and A/R will be even more crucial for a rear mount TT.
+1 and the most expensive thing...time
By the way, I only have a TP and the crappy Utec BCS. My exhaust is not Jet-Hot coated, No heat wrap on the exhaust, no turbo blanket, no wrap on the headers and to make things worst, all my charge pipe underneath the car is also not Jet-Hot coated
Just a regular pipe with a paint.. lol Granted I was the first one who had the modified piping that MRC fabricated and STS didnt send him some coated pipe.
Just a regular pipe with a paint.. lol Granted I was the first one who had the modified piping that MRC fabricated and STS didnt send him some coated pipe.
What about headers? i was thinking about using long tube headers. I read about them on these forums https://my350z.com/forum/na-builds/3...-roadster.html
Last edited by athensgls; Aug 11, 2009 at 03:47 PM.