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Project Light Speed Part 2 - LS1 Engine Header Test

As we all know, aftermarket headers are a great way to wake up any performance car. Which ones are best? How large should they be? Longtubes or shorties? We exhaust every possibility by testing a vast array of LS1 headers on the dyno so you know what's

Photography by
Ls1 Header Test Tts 158
The Turbo Shop (TTS) supplied the headers for our test. They don't make a production set of 1 5/8-inch headers for a late-model Camaro, but they whipped up a custom set for us. Our testing revealed why TTS chose not to build these smaller headers!
Ls1 Header Test Tts 158
The Turbo Shop (TTS) supplied the headers for our test. They don't make a production set o

Evaluation

So what did we learn from this exhaustive flog-fest? First, the Vette manifolds for a stock LS1 even at the 400hp level, are extremely efficient. We learned that larger primary pipe tubes tend to work well on a stock LS1, which leads us to think they will work even better on a modified engine with a better cam and heads. There is data to support the notion that longer primary pipe lengths approaching 40 inches plus a longer collector length may be worth more torque. Generally, we'll see torque improvements with a longer collector, but these TTS headers were designed to fit in a late-model F-car as opposed to perhaps a first-gen Chevelle or Camaro where there would be more room for a longer collector and primary pipe lengths.

Ls1 Header Test Tts Flange
The TTS headers feature extremely thick 1/2-inch flanges to prevent warping, so all we had to do was bolt them on using ARP's metric header bolts.
Ls1 Header Test Tts Flange
The TTS headers feature extremely thick 1/2-inch flanges to prevent warping, so all we had

The bottom line is that a stockLS1 can obviously make as much as 400 hp using stock Vette iron exhaust manifolds, so don't toss those Vette pieces in the trash! It is also clear that the right size headers can still improve power on one of these engines with the right combination of parts.

Stick with us as we look into the best ways to make more power with our GM Performance Parts LS1. The idea here is to make power without resorting to spending a ton of money. We want to make this LS1 sing for a song.



  • Ls1 Header Test O2 Sensor Bung
    The TTS headers also incorporate an oxygen-sensor bung in the header to supply the feedback information the computer needs.
    Ls1 Header Test O2 Sensor Bung
    The TTS headers also incorporate an oxygen-sensor bung in the header to supply the feedbac
  • Ls1 Header Test Tts 134
  • Ls1 Header Test Tts 178
    The next two TTS headers we tested were very similar except for their primary pipe size measuring 1 3/4 (left) and 1 7/8 inches in diameter (right).
    Ls1 Header Test Tts 178
    The next two TTS headers we tested were very similar except for their primary pipe size me
Power Numbers
  Avg. Avg. Peak Peak
Combo TQ HP TQ HP
LS1 Vette
Manifolds
369.7 301.2 391 @
4,900
396 @
6,100
LS1 Camaro
Manifolds
360.5 292.3 384 @
4,400
384 @
5,700
TTS 1 5/8
Headers
372.4 301.9 397 @
4,400
396 @
5,600
TTS 1 3/4
Headers
372.5 302.5 396 @
5,000
396 @
5,700
TTS 1 7/8
Headers
373.1 303.3 396 @
4,400
402 @
5,800
Parts List
Component Mfr. PN
LS1 crate engine GMPP 25534322
Oxygen sensor, Corvette GM 25312184
Mass airflow sensor, F-car GM 25179711
Mufflers Flowmaster 952545
Fuel-pressure regulator Aeromotive 13109
Header gasket GMPP 12576221
Header, 1 3/4 inch TTS Call
Header, 1 7/8 inch TTS Call
Dyno Numbers
Rather than list all five tests, we decided to compare the stock Vette manifolds against the best overall headers, which were the TTS 1 7/8-inch diameter headers based on overall power. As you can see, there were only minor differences. Clearly, the stock iron manifolds are very well designed.
 
TEST 1
TEST 1
   
 
Vette
Manifolds
1 7/8
Headers
DIFF
RPM
TQ
HP
TQ
HP
TQ
HP

2,600

348

172

348

172



2,800

348

186

351

187

+3

+1

3,000

351

201

351

201



3,200

363

221

363

221



3,400

363

235

364

236

+1

+1

3,600

371

254

375

257

+4

+3

3,800

374

271

373

270

–1

–1

4,000

386

294

379

288

–7

–6

4,200

385

308

390

312

+5

+4

4,400

389

326

396

332

+7

+6

4,600

387

339

389

340

+2

+1

4,800

390

356

393

359

+3

+3

5,000

390

371

395

376

+5

+5

5,200

385

382

389

385

+4

+3

5,400

381

392

378

388

–3

–4

5,600

367

392

370

394

+3

+2

5,800

356

393

364

402

+8

+9

6,000 339 387 346 396 +7 +9
SOURCES
Automotive Racing Products (ARP)
531 Spectrum Circle
Oxnard
CA  93030
805-278-7223
GM Performance Parts
www.gmperformanceparts.com
EFILive Scoggin-Dickey Parts Center
Lubbock
TX
N/A
www.sdparts.com
Flowmaster
8-00/-544-4761
www.flowmastermufflers.com
The Turbo Shop (TTS)
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