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Thread: Went to the dyno today

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Posts: 31-40 of 58
2009-05-14 20:55:16
#31
Originally Posted by Doctor
Okay okay stop the bus. My bad. We are at 1740meters above sea level. Not feet.

Thus, 5707ft altitude. 3%*5707 / 1000 = 17% which explains everything.

So we can assume at altitude my power figure would be around the 210whp mark... give or take 2-3 hp.


geez i was just gonna say now dude. I stay in kbly and we at 3300FT ASL.


Great numbers think you should post a vid up i wana hear them itb's
2009-05-14 21:01:35
#32
Originally Posted by Doctor
Interesting. The guy who did my motor did mention even the low lobes had crazy duration, so it's possible yes. And he physically measured the actual degrees at which the valves start opening until they close, so I know his figures are correct. What compression did you run when you got those psi figures with the cams?

After I've played with the FS4 cam timing on the dyno I'll be throwing in derms' N1 cams for comparison. Will do another compression test then. How did your motor respond after switching from fs4's to n1's?

The runners from bellmouth to the head are aproximately 21cm or about 8 1/4 inches. It's shorter than usual, due to space constraints on the RHD model. Being that short it's great for high rpm power, but I think the cams are possibly messing things around a bit.


I'm running 11:1 with 20V pistons.

The N1 is a lot better below 6,000rpm. From 7,000-9,000, the FS4 felt better. The N1 runs out steam after 7,500. Each has it strong points so I wound up mixing them up.

On a side note, the sound from the FS4 is crazy as you know. Some people think the N1's are loud but they have not heard the FS4. Not even close.

Your intake runners are close to the factory length, which is 8.5". The factory length are meant for 7,000-7,500 rpm. You need to shorten the air horns. You should be aiming for 7" for the runners, that will put you at around 8,000 rpm for peak power.
2009-05-14 21:08:02
#33
Originally Posted by Benito
I'm not all that much of an itb fan either. I can vouch for the coast/upland dyno numbers differing down there in ZA. Also I can vouch for the fact that they swear by itbs.

I think the N1s will help too. FS4 is for the scrap bin.


Too much reading internet misinformation and not enough first hand experience.
2009-05-14 21:24:24
#34
Originally Posted by 5speed
Too much reading internet misinformation and not enough first hand experience.


who me or someone else? And which point?
2009-05-14 21:30:29
#35
Originally Posted by kesi24
You might want to look into a evac system, plumb the crank case/valve cover to a check valve hooked up to the header to suck the pressure out, that how we do it in all the car's in NY.


Can you or someone further explain that and what it does please. Im a little lost i don't know if im reading wrong or if i don't know what that means. Thanks in advance.
2009-05-14 21:35:55
#36
Originally Posted by se-riousjdm
Can you or someone further explain that and what it does please. Im a little lost i don't know if im reading wrong or if i don't know what that means. Thanks in advance.


It plumbs your pressure/blow-bye oil out of the intake and into the exhaust stream. Keeps oil out of the intake, and relieves crank case pressurizing.
2009-05-14 22:48:55
#37
Originally Posted by 5speed
Too much reading internet misinformation and not enough first hand experience.


Yes 5 speed is correct fs4 makes good power but the problem is its out of the range for the average folk, 8500-9800 rpm type of camshaft .Also about itb's are too long as stated .I wish you can do one mod at a time to see what actually hurting your #'s.

Originally Posted by se-riousjdm
Can you or someone further explain that and what it does please. Im a little lost i don't know if im reading wrong or if i don't know what that means. Thanks in advance.


Google it buddy! most likely it wont help the average motor setup unless you have a serious setup.
2009-05-14 23:33:08
#38
Originally Posted by Doctor
Interesting. The guy who did my motor did mention even the low lobes had crazy duration, so it's possible yes. And he physically measured the actual degrees at which the valves start opening until they close, so I know his figures are correct. What compression did you run when you got those psi figures with the cams?

After I've played with the FS4 cam timing on the dyno I'll be throwing in derms' N1 cams for comparison. Will do another compression test then. How did your motor respond after switching from fs4's to n1's?

The runners from bellmouth to the head are aproximately 21cm or about 8 1/4 inches. It's shorter than usual, due to space constraints on the RHD model. Being that short it's great for high rpm power, but I think the cams are possibly messing things around a bit.


yeah i would probably shorten them about an inch
2009-05-15 05:49:22
#39
Originally Posted by 5speed


The N1 is a lot better below 6,000rpm. From 7,000-9,000, the FS4 felt better. The N1 runs out steam after 7,500. Each has it strong points so I wound up mixing them up.

On a side note, the sound from the FS4 is crazy as you know. Some people think the N1's are loud but they have not heard the FS4. Not even close.


Yeah man those FS4's certainly POP! Especially with the ITB's it sounds like a fighter jet when they kick in. And then the rev counter spins like it's gone crazy. If I'm not carefull I run into the 8500 limiter every gear.

On a side note, let's assume with dialing the cams a bit there are a few hp more to be had. Would it really be such a terrible thing if these cams peaked around 7500-8000rpm? Personally I think not. I know it sounds nice to tell your friends you make power to 9500rpm but if you can make that power without revving the tits off your motor then the motor will be saved for longer. It's different if they made great numbers from 7500rpm and held it all the way thorugh to 9 or 9.5k. That I could see the benefit in.
2009-05-15 21:04:10
#40
Originally Posted by Doctor
Yeah man those FS4's certainly POP! Especially with the ITB's it sounds like a fighter jet when they kick in. And then the rev counter spins like it's gone crazy. If I'm not carefull I run into the 8500 limiter every gear.

On a side note, let's assume with dialing the cams a bit there are a few hp more to be had. Would it really be such a terrible thing if these cams peaked around 7500-8000rpm? Personally I think not. I know it sounds nice to tell your friends you make power to 9500rpm but if you can make that power without revving the tits off your motor then the motor will be saved for longer. It's different if they made great numbers from 7500rpm and held it all the way thorugh to 9 or 9.5k. That I could see the benefit in.


If you want peak power to be around 7500-8000, then I say go with the N1. That's where they were designed to run. The FS4 above 8,000.

There's no such thing as a "perfect cam". Each camshafts was designed for the desired rpm range. Here's an illustration, lets look at the stock camshaft. The low cam, with it's short lift and duration, was meant to run below 5,000 rpm. It's not going to make more horsepower than the high cam above 6,000 and vice versa, the high cam won't make more hp than the low cam below 5,000. Each was designed for the desired rpm range. That's why we play around with the activation points.

Now back to the N1 and the FS4. The FS4 is a lot bigger in duration than the N1, so it naturally wants to run higher up in the rpm range. If the engine package(header, intake manifold, compression ratio) doesn't match up with the cam, the engine will underperform.
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