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3400 Stock manifolds vs WOT-Tech Competition Ported vs Stock Bare Head
This is a pretty straight forward comparison showing the flow at the intake valve for a stock bare head (what you normally see for flow numbers) against what the engine really flows with the manifolds and throttle body on there. First is stock, which is the benchmark standard for our Dynomation cam selection on stock engines. If you are doing any sort of engine simulation, it is important that your data is as accurate as possible. This means what the engine flows as a unit. Not doing so will skew cam specs and inflate simulation results.
At .500 lift (most common value despite its lack of real value to a stock 3400) the stock head flows 214 cfm. With the manifolds, its 174.4. Porting them puts it up to 185.1 (in 2006).
Dynomation Results for Stock vs WOT-Tech Ported Manifolds
This is simulated crank HP using the flow numbers for the complete stock intake setup and our 2006 ported manifolds. Stock throttle body still being used. +9HP, +8TQ.
56mm vs 65mm TB flow at the valve
This is an unknown 3500 setup used to compare the flow at the intake valve when using a 56mm TB, and a 65mm TB. It is a small but measurable improvement in static flow on a single open valve. These changes are used for our simulations as well, which already take into account the overall flow improvement (327 vs 440 CFM @ 1.5 inHg)
3400 Head with Small Port Manifolds vs Large Port vs 3500 with Stock Manifolds vs 3900 VVT Open vs VVT Closed vs 3900 Non Variable Upper
This should be interesting for the 3900 owners. I am certain no one else is going to have this info to share, and I think it makes the most impact on anyone that believes we are wasting our time telling everyone that the manifold flow is important. Click the link, print it out...and follow along
First we have a stock 3400 head, because I never flowed the small port head with the small port manifolds. It would be more dramatic, as I have flowed the stock head bare and its 202 vs 214 @ .500". 3400 with small port is 162.4 cfm @ .500.
Lets jump to the good bit. Go to test No. 5. Stock 3900 head with stock manifolds, VVT upper, Closed Vane. 168.3 cfm @ .500.
Your 3900 flows about the same as a slightly overclocked small port 3100 while cruising around. No big deal though right, when you lay into it, its gonna open that vane and surely flow a lot. Test No. 4, Open vane. 183.1 CFM, or a 15cfm improvement. Pretty sweet, until you look at the stock 3400 and 3500 head/manifold setups and see they flow 174.4 and 176.7 respectively. More displacement, not a big improvement in flow.
So how about some good news. The non variable 3900 upper jumps up to 205.6 cfm @ .500. That's 22cfm over the variable.
Of course the non .500 numbers are very interesting as well between all these setups.
3.4 DOHC Stock vs Ported Flow
Josh (the previous owner of my grand prix) had someone local to him port the heads, and we flowed the heads while they were at the shop getting new guides all around and milled. That was about it as far as LQ1 testing is concerned. We may do the stock 96-97 heads once the new bench is done. We have a set, but its hard to rationalize rebuilt heads vs a set that needs the same work done at least.
This is a pretty straight forward comparison showing the flow at the intake valve for a stock bare head (what you normally see for flow numbers) against what the engine really flows with the manifolds and throttle body on there. First is stock, which is the benchmark standard for our Dynomation cam selection on stock engines. If you are doing any sort of engine simulation, it is important that your data is as accurate as possible. This means what the engine flows as a unit. Not doing so will skew cam specs and inflate simulation results.
At .500 lift (most common value despite its lack of real value to a stock 3400) the stock head flows 214 cfm. With the manifolds, its 174.4. Porting them puts it up to 185.1 (in 2006).
Dynomation Results for Stock vs WOT-Tech Ported Manifolds
This is simulated crank HP using the flow numbers for the complete stock intake setup and our 2006 ported manifolds. Stock throttle body still being used. +9HP, +8TQ.
56mm vs 65mm TB flow at the valve
This is an unknown 3500 setup used to compare the flow at the intake valve when using a 56mm TB, and a 65mm TB. It is a small but measurable improvement in static flow on a single open valve. These changes are used for our simulations as well, which already take into account the overall flow improvement (327 vs 440 CFM @ 1.5 inHg)
3400 Head with Small Port Manifolds vs Large Port vs 3500 with Stock Manifolds vs 3900 VVT Open vs VVT Closed vs 3900 Non Variable Upper
This should be interesting for the 3900 owners. I am certain no one else is going to have this info to share, and I think it makes the most impact on anyone that believes we are wasting our time telling everyone that the manifold flow is important. Click the link, print it out...and follow along
First we have a stock 3400 head, because I never flowed the small port head with the small port manifolds. It would be more dramatic, as I have flowed the stock head bare and its 202 vs 214 @ .500". 3400 with small port is 162.4 cfm @ .500.
Lets jump to the good bit. Go to test No. 5. Stock 3900 head with stock manifolds, VVT upper, Closed Vane. 168.3 cfm @ .500.
Your 3900 flows about the same as a slightly overclocked small port 3100 while cruising around. No big deal though right, when you lay into it, its gonna open that vane and surely flow a lot. Test No. 4, Open vane. 183.1 CFM, or a 15cfm improvement. Pretty sweet, until you look at the stock 3400 and 3500 head/manifold setups and see they flow 174.4 and 176.7 respectively. More displacement, not a big improvement in flow.
So how about some good news. The non variable 3900 upper jumps up to 205.6 cfm @ .500. That's 22cfm over the variable.
Of course the non .500 numbers are very interesting as well between all these setups.
3.4 DOHC Stock vs Ported Flow
Josh (the previous owner of my grand prix) had someone local to him port the heads, and we flowed the heads while they were at the shop getting new guides all around and milled. That was about it as far as LQ1 testing is concerned. We may do the stock 96-97 heads once the new bench is done. We have a set, but its hard to rationalize rebuilt heads vs a set that needs the same work done at least.
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