Dyno Day!
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,743
Likes: 37
From: Stockton Ca
Dyno Day!
I finally made the trip to the Dynojet Dyno. First baseline run was 202 HP & 266TQ. Finished w/280 HP & 314 TQ.
350 +.60 TFS heads, Air Gap, Demon 650VS, 218-224 HR w/1.6 RRs, stock rams horns and dented duals.
Car was jetted down 2 sizes from stk w/68/76 as per Lars.
The baseline was scattered below 3K due to lean condition + too much advance (manifold vac). Went to larger squirter, port vac and #86 jets on sec. Engine ran best on 32* total.
TQ was 313 from 3800-4100, Hp started flattening out @5K 275 HP and peaked @5400 w/279 HP.
Dyno operator felt that ex was holding combo back 25 RWHP. I'm happy so far. I hope that headers and duals are worth more than 25 HP?
Still a little weak off idle @800rpm. I'm going to raise idle and drive it for awhile! MPG seems better, a road trip will tell the truth!
Rick
350 +.60 TFS heads, Air Gap, Demon 650VS, 218-224 HR w/1.6 RRs, stock rams horns and dented duals.
Car was jetted down 2 sizes from stk w/68/76 as per Lars.
The baseline was scattered below 3K due to lean condition + too much advance (manifold vac). Went to larger squirter, port vac and #86 jets on sec. Engine ran best on 32* total.
TQ was 313 from 3800-4100, Hp started flattening out @5K 275 HP and peaked @5400 w/279 HP.
Dyno operator felt that ex was holding combo back 25 RWHP. I'm happy so far. I hope that headers and duals are worth more than 25 HP?
Still a little weak off idle @800rpm. I'm going to raise idle and drive it for awhile! MPG seems better, a road trip will tell the truth!
Rick
Team Owner
Joined: Feb 2005
Posts: 32,519
Likes: 1
From: central America
St. Jude Donor '08-'09
Which Trick flow heads were you using? What's the lift on your cam? What's your compression ratio? Details, man, we need details!
Those are awesome numbers! I'm thinking I may have to do a head swap to get the 300 hp at the rear wheels like I want.
trw
Those are awesome numbers! I'm thinking I may have to do a head swap to get the 300 hp at the rear wheels like I want.
trw
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
Rick - Did it really take 86 jets? Were you running a sniffer on the pipes? My 750 speed demon only has 82's on the secondary and the sniffer kept mine at 12.8 A/f at WOT. That is at my altitude. But sea level only is a jet or two at most for sea level.
Headers for sure!
June is the All Vette drags at Sacramento raceway!
Headers for sure!
June is the All Vette drags at Sacramento raceway!
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,743
Likes: 37
From: Stockton Ca
George: I couldn't believe it either. After baseline things, he put it on the sniffer and it can almost pass smog. After the printout from 1st run, operator says that a 10 point increase in jetting was needed. Who am I to tell him his business. He thinks I might have major backpressure w/stk ex and smashed pipes. I was hoping for 325 RWHP w/headers!
He must be doing something right, had some very nice rods waiting to be worked on. Time will tell.
Rick
He must be doing something right, had some very nice rods waiting to be worked on. Time will tell.
Rick
Team Owner
Joined: Apr 1999
Posts: 21,953
Likes: 1,445
From: Reno Nevada
2024 C3 of the Year Finalist- Modified
I'd like to see the A/F ratio graph during the final run. Generally headers tend to lean out the A/F ratio. It all has to do with better cylinder scavaging. Just headers with muffler to uncapped headers at the track my pipes would turn white unless I rejetted a size bigger.
Not every carb designed is the same. But I'm convinved that you want to run your secondaries within 6-8 jet sizes of the primary side. The primary has smaller jets because of the idle circiut and the power valve etc giving it a lean cruise and additional fuel to equal the richer jetted secondaries.
Not every carb designed is the same. But I'm convinved that you want to run your secondaries within 6-8 jet sizes of the primary side. The primary has smaller jets because of the idle circiut and the power valve etc giving it a lean cruise and additional fuel to equal the richer jetted secondaries.
Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,743
Likes: 37
From: Stockton Ca
George: The final AF is between 13-14. I asked about the 6-8 size difference on jetting. He said that it is ballpark not final. He left primary at 68 but went bigger on squirter from 40-45. He also played w/secondaries spring, ended up w/std spring. If he messed up, I can't tell.
Rick
Rick
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Thread Starter
Drifting
Joined: Apr 2002
Posts: 1,743
Likes: 37
From: Stockton Ca
Sorry, I forgot to mention that a carb w/vacume sec like my 650VS sometimes needs extra jet. Something about more fuel to make up for what the vac sec isn't giving it. I bet that mech sec follow the rule much better. I hope that explains it?
Rick
Rick