Opinions on odd dyno results.
06-05-2003, 09:14 PM
#11
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Join Date: Apr 2003
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Re:Opinions on odd dyno results.
Originally Posted by REDLINE
Whats so odd? That you have a big power drop when the Vtec kicks in? I don't give a ---- if it kicks in at 3, 4, 5 or 7 grand you will always have that drop. This is why I feel the Vtec is only good on N/A motors. Elimidate your Vtec and it won't do that anymore. Because that 30hp a Vtec gives you will hurt you in a 1/4 mile. Yes you start with a extra 30hp than a non Vtec (b16 vs ZC or b18c vs b18b) has but the non Vetc has about 20 lbs more torque! If you run the same turbo and mods the Vtec will get beat in a 1/4 mile. Why because you will lose 30hp for a brief sec. as your Vtec (you 30hp edge) kicks in. this will drop your 1/4 mile time down at least 1/2 second.
Since when does a ZC make 120lbs at the wheels??
Anyways, that severe of a drop is NOT normal, hence I am aksing for opinions... MOST have been helpful...
Read some more dyno charts of mild B16 turbo setups, and you'll realize that the drop, although present, is far from being as abrupt as the one on the graphs I posted.
Thanks for your help...
-Tom
06-06-2003, 05:56 AM
#12
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Join Date: Dec 2002
Posts: 3,830
Re:Opinions on odd dyno results.
My dyno graph is a bit skewed do to my then non-functional-homemade boost controller. That run had about 4-5psi till 5000, then crept to 8 by 7500. The vtec was moved to 5400 which got rid of the dip completely. Seemless transition. VTEC and boost DO work. Dont believe the 'Overlap' myth 
Also of note, was unknown till later, my timing was very conservative. Here is the map that run was made on: All #s are actually 3 degrees lower than what I 'thought' RomEditor showed due to an error entering 'base timing' correctly into RomEditor. I was running 18.5 at 8psi which is 1.5 per psi. Way to conservative.
Here is an interesting datalog of boost reposnse with a roll on in 3rd gear. (fixed the boost controller) 9-9.5psi by 3300. With lower load, a roll in 2nd is around 3800.
While Im posting Datalogs, here is one of when I got my Ghetto 2stage controller working. Switching between 4 and 8psi while at close to WOT.
That RHB5 is making good lowend and midrange, but is turning into a weezing space-heater on the top end. Id put money on a (if you wanna stay low budget) T3 with a .63 housing making good power on those ITR cams (w/ VTEC at 6000ish). (assuming you switch to larger injectors, smooth the A/F, uncork the exhaust, and get the IC some fresh air)
Update us when you guys get it sorted, I wanna see what those cams can really do
Also of note, was unknown till later, my timing was very conservative. Here is the map that run was made on: All #s are actually 3 degrees lower than what I 'thought' RomEditor showed due to an error entering 'base timing' correctly into RomEditor. I was running 18.5 at 8psi which is 1.5 per psi. Way to conservative.
Here is an interesting datalog of boost reposnse with a roll on in 3rd gear. (fixed the boost controller) 9-9.5psi by 3300. With lower load, a roll in 2nd is around 3800.
While Im posting Datalogs, here is one of when I got my Ghetto 2stage controller working. Switching between 4 and 8psi while at close to WOT.
That RHB5 is making good lowend and midrange, but is turning into a weezing space-heater on the top end. Id put money on a (if you wanna stay low budget) T3 with a .63 housing making good power on those ITR cams (w/ VTEC at 6000ish). (assuming you switch to larger injectors, smooth the A/F, uncork the exhaust, and get the IC some fresh air)
Update us when you guys get it sorted, I wanna see what those cams can really do
06-08-2003, 01:42 AM
#13
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Join Date: Dec 2002
Posts: 13,991
Re:Opinions on odd dyno results.
Originally Posted by REDLINE
Whats so odd? That you have a big power drop when the Vtec kicks in? I don't give a ---- if it kicks in at 3, 4, 5 or 7 grand you will always have that drop. This is why I feel the Vtec is only good on N/A motors. Elimidate your Vtec and it won't do that anymore. Because that 30hp a Vtec gives you will hurt you in a 1/4 mile. Yes you start with a extra 30hp than a non Vtec (b16 vs ZC or b18c vs b18b) has but the non Vetc has about 20 lbs more torque! If you run the same turbo and mods the Vtec will get beat in a 1/4 mile. Why because you will lose 30hp for a brief sec. as your Vtec (you 30hp edge) kicks in. this will drop your 1/4 mile time down at least 1/2 second.
Thanks for the correction, I just wasnt use to seeing the torque jump way higher than the HP, now that you said that it does make sense. As Dave said, that little rhb5 is doing you no good, especially with a log type manifold. B16a's like to breath
Jeff
06-09-2003, 10:42 AM
#14
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Join Date: Feb 2003
Posts: 0
Re:Opinions on odd dyno results.
Nice to see old skool Hybrid people here
The "problem" is the injectors. They hit 100% duty cycle and the AF climbs. Get 450cc or bigger and the owner will be happy.
The IHI is going to be the next restriction. For budget builds by people who don't have fabricational skills, getting a tubular manifold set up for flow is probably unlikely. The guy can look for a VJ23 compressored RHB5 off an 87-88 Thunderchicken for something that bolts on... it will be a noticeable but not great improvement. I'd recommend he replaces the manifold's flange with T3 and find .60 trim .63 AR unit from 84-87 Ford 2.3T or 84-87 300ZX. A peaky hybrid turbo would really suit that B16, but some people don't want to spend that money. *shrug*
I'd keep the ITR exhaust cam, switch back to B16 intake cam, and dial out some overlap with cam gears... wait, no I wouldn't. That stuff costs too much money. I think I'd just keep feeding the engine more boost until I was a God... or a jackass with a rod sticking out of his block. :>
The "problem" is the injectors. They hit 100% duty cycle and the AF climbs. Get 450cc or bigger and the owner will be happy.
The IHI is going to be the next restriction. For budget builds by people who don't have fabricational skills, getting a tubular manifold set up for flow is probably unlikely. The guy can look for a VJ23 compressored RHB5 off an 87-88 Thunderchicken for something that bolts on... it will be a noticeable but not great improvement. I'd recommend he replaces the manifold's flange with T3 and find .60 trim .63 AR unit from 84-87 Ford 2.3T or 84-87 300ZX. A peaky hybrid turbo would really suit that B16, but some people don't want to spend that money. *shrug*
I'd keep the ITR exhaust cam, switch back to B16 intake cam, and dial out some overlap with cam gears... wait, no I wouldn't. That stuff costs too much money. I think I'd just keep feeding the engine more boost until I was a God... or a jackass with a rod sticking out of his block. :>
06-10-2003, 11:46 PM
#15
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Join Date: Apr 2003
Posts: 27
Re:Opinions on odd dyno results.
Very well... thanks for the educational replies.
Yes, hybrid people are roaming all over the place nowadays, not so much on hybrid anymore... =/
(not speaking for anyone else, just myself).
So we are all in agreement that the injectors have to be replaced in favour of larger ones.
Turbo will stay for now... its a long story, but the owner paid a grip for this very non functional turbo setup. I am playing damage control by making the best of a bad situation. I will relay to him all of your suggestions.
As per REDLINE, I think first order of business is to get rid of that POS B16 and slap an allmighty ZC in there... naah wait, we'll go all out and get a 12 valve CVCC, get that precombustion chamber under pressure, that will light up that lean mixture in a flash!
One somewhat technical question, hopefully someone will clear up for me:
an engine takes the most fuel at torque peak, in this case between 3800 and 4800rpm (thats what I seem to remember), is that why the mixture richens up towards the top end? Could pulse width be greater at 4800 than 7500rpm, fuel pressure and boost pressure beeing the same throughout the run.
Looking at my B20 vtec dyno run, the mixture is also lean at the lower end and richens towards higher rpms...
-Thomas
Yes, hybrid people are roaming all over the place nowadays, not so much on hybrid anymore... =/
(not speaking for anyone else, just myself).
So we are all in agreement that the injectors have to be replaced in favour of larger ones.
Turbo will stay for now... its a long story, but the owner paid a grip for this very non functional turbo setup. I am playing damage control by making the best of a bad situation. I will relay to him all of your suggestions.
As per REDLINE, I think first order of business is to get rid of that POS B16 and slap an allmighty ZC in there... naah wait, we'll go all out and get a 12 valve CVCC, get that precombustion chamber under pressure, that will light up that lean mixture in a flash!
One somewhat technical question, hopefully someone will clear up for me:
an engine takes the most fuel at torque peak, in this case between 3800 and 4800rpm (thats what I seem to remember), is that why the mixture richens up towards the top end? Could pulse width be greater at 4800 than 7500rpm, fuel pressure and boost pressure beeing the same throughout the run.
Looking at my B20 vtec dyno run, the mixture is also lean at the lower end and richens towards higher rpms...
-Thomas
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