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Who's interested in Dyno data for custom manifold vs ported stock manifold ?

Cliff's: 32 wHP and 10 wTQ

Details:
I have a SFS GT28 V3 kit that until recently had an early SFS custom welded tubular manifold. Setup includes 264 cams, stock/Gforce ECU, SAFC2, meth/water injection.

As I posted last page, my custom exhaust manifold developed multiple cracks. I recently replaced it with my stock manifold after $200 of porting. The porting work looks great, there are some pics last page too. I was hoping I'd see minimal power drop off, but regardless I am happy to have no further concerns about manifold failure. I suppose the driving experience is more influenced by TQ than HP, and down 10 TQ is pretty minor. The car is now issue-free and the most completely dialed-in that it has been for my 4 years of STU Hybrids ownership.

91 oct + meth:
Custom mani 534 hp 486 tq
Stock mani. 502 hp 476 tq

96 - 100 oct + meth:
Custom mani 555 hp 500 tq
Stock mani 523 hp 490 tq

Dyno comparison variables:

Both were on the same dyno. The custom manifold runs were done in 2016, ambient temp 100. The high octane pulls in 2016 were on a mix of about 100 octane. The 2019 stock mani pulls were ambient temp 80, high octane pulls were on a mix of about 96 octane. The A/F adjustments had been tinkered with over the intervening years, but on both sets of dynos A/F was adjusted to target of about 11.5

Graphs below are for the 91 octane pulls

2016 Custom Manifold:

242624

2019 Ported Stock Manifold:

242625
 

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Stock Twins King
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4,415 Posts
I received an update on the combo manifold. The first test piece is done and in the jig for further modification for bolt holes, etc. I heard they will be done in 2 weeks. (heard this like 50x). We did find errors a few weeks ago that have been remedied.



 

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Stock Twins King
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4,415 Posts
Got a few more pics. This is the prototype...If I approve then they will cast the 10 units in 2 weeks.
 

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Who's interested in Dyno data for custom manifold vs ported stock manifold ?

Cliff's: 32 wHP and 10 wTQ

Details:
I have a SFS GT28 V3 kit that until recently had an early SFS custom welded tubular manifold. Setup includes 264 cams, stock/Gforce ECU, SAFC2, meth/water injection.

As I posted last page, my custom exhaust manifold developed multiple cracks. I recently replaced it with my stock manifold after $200 of porting. The porting work looks great, there are some pics last page too. I was hoping I'd see minimal power drop off, but regardless I am happy to have no further concerns about manifold failure. I suppose the driving experience is more influenced by TQ than HP, and down 10 TQ is pretty minor. The car is now issue-free and the most completely dialed-in that it has been for my 4 years of STU Hybrids ownership.

91 oct + meth:
Custom mani 534 hp 486 tq
Stock mani. 502 hp 476 tq

96 - 100 oct + meth:
Custom mani 555 hp 500 tq
Stock mani 523 hp 490 tq

Dyno comparison variables:

Both were on the same dyno. The custom manifold runs were done in 2016, ambient temp 100. The high octane pulls in 2016 were on a mix of about 100 octane. The 2019 stock mani pulls were ambient temp 80, high octane pulls were on a mix of about 96 octane. The A/F adjustments had been tinkered with over the intervening years, but on both sets of dynos A/F was adjusted to target of about 11.5

Graphs below are for the 91 octane pulls

2016 Custom Manifold:

View attachment 242624
2019 Ported Stock Manifold:

View attachment 242625
By changing the manifold it looks like you are making 300 tq around 3200rpm, before you were making that around 4200rpm.

To me your power delivery looks much better with the ported OEM manifold :)
 

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By changing the manifold it looks like you are making 300 tq around 3200rpm, before you were making that around 4200rpm.

To me your power delivery looks much better with the ported OEM manifold :)
Ya know Ben , I had not really spotted that - thx!

I'm very happy with the set up now. There was also a bit of roughness in the decel when coming off hard-throttle with the custom mani, that is gone now.
 

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Ya know Ben , I had not really spotted that - thx!

I'm very happy with the set up now. There was also a bit of roughness in the decel when coming off hard-throttle with the custom mani, that is gone now.
You can see that difference in the transition between turbo 1 and turbo 2, the OEM manifold looks a lot better overall.
 

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Stock Twins King
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After 5 years of R&D and WAY too much money lol! the first prototype is done. This one is going to a GT28 owner who has dyno'd with the OEM log. He is going to install this to see what gains he makes. I am hoping maybe 30hp but it should be a very efficient 30hp with no turbulence. Notice the new oval concave's where the nuts go. This is a huge advantage for getting these nuts on and off way better. Flow bench is showing a 70% flow gain over OEM except for the center ports which is less than 20%. The even made the flange a hair thinner so heat dissipation is uniform. I had 2 Engeineers working this and they thought about a lot of ideas to incorporate.





Properties 304 vs OEM cast iron



But there is still more wait time. Now that we have approved this proto, it will take about 3 weeks to pour the remaining 10 I contracted for. I haven't decided if I will add another 10 or not.

As I had mentioned way back, I plan on selling these for $1200 ea. I will be losing money at this but will make it up if I do another 10 units. I will also have a new batch of enlarged EBV bpass tubes as well for $220 ea


 

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I am in for one STU, I’ll happily pay that price. Just pm me.
 
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