dyno tuning boosted vtec engines.....[Q]
04-22-2002, 02:03 PM
#1
Member
Thread Starter
Join Date: Sep 2001
Posts: 1,071
Likes: 0
Received 0 Likes
on
0 Posts
dyno tuning boosted vtec engines.....[Q]
a few guys ive talked to have mentioned to dissable VTEC
when dyno tuning to tune your AF ratio. using a WB o2 sensor
reason: the vtec lobes have more overlap and give richer
AF ratios reading than the motor is acctually seeing. its not an accurate
reading of what the motor is actually burning because of the overlap.
they suggested to tune the car with VTEC disabled, establish a
good AF ratio with my cartech FMU, and then activate VTEC again.
comments..suggestions..
i have a cartech FMU 20005, bosch pump, h22 injectors. 5-6 psi IHI turbo
im dyno tuning my 1st gen B16a soon i dont want to blow it up..thanks
when dyno tuning to tune your AF ratio. using a WB o2 sensor
reason: the vtec lobes have more overlap and give richer
AF ratios reading than the motor is acctually seeing. its not an accurate
reading of what the motor is actually burning because of the overlap.
they suggested to tune the car with VTEC disabled, establish a
good AF ratio with my cartech FMU, and then activate VTEC again.
comments..suggestions..
i have a cartech FMU 20005, bosch pump, h22 injectors. 5-6 psi IHI turbo
im dyno tuning my 1st gen B16a soon i dont want to blow it up..thanks
04-22-2002, 02:18 PM
#2
Trial User
Join Date: May 2000
Location: Los Angeles, CA
Posts: 7,033
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (Giuseppe)
dyno tune that car with vtec still hooked up...
the dyno will show you the air/fuel all the way, and you can tune it from there..
why disable stuff.. your gonna drive it with the vtec solinoid working... why not tune it that way...
the dyno will show you the air/fuel all the way, and you can tune it from there..
why disable stuff.. your gonna drive it with the vtec solinoid working... why not tune it that way...
04-22-2002, 03:07 PM
#4
Member
Thread Starter
Join Date: Sep 2001
Posts: 1,071
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (turbo Si)
i have stock cam gears, and have no way of tuning
out overlap.
quote "in VTEC the overlap of the cams causes
an innacurate AF ratio, instead of fuel being burned, it just exists
via the exhaust valve because of the vaccum created by the overlap.
A WB o2 sensor indicates the motor is running at a 12.5:1 mixture,
but infact it isnt burning a 12.5:1 AF ratio, but rather burning at a leaner
mixture." end quote
ive seen a motor on the dyno blow up when VTEC hit,
the reason above was the explanation by the shop.
so this is why i ask...thanks!
out overlap.
quote "in VTEC the overlap of the cams causes
an innacurate AF ratio, instead of fuel being burned, it just exists
via the exhaust valve because of the vaccum created by the overlap.
A WB o2 sensor indicates the motor is running at a 12.5:1 mixture,
but infact it isnt burning a 12.5:1 AF ratio, but rather burning at a leaner
mixture." end quote
ive seen a motor on the dyno blow up when VTEC hit,
the reason above was the explanation by the shop.
so this is why i ask...thanks!
04-22-2002, 03:43 PM
#5
Honda-Tech Member
Join Date: Jun 2001
Location: Canada City
Posts: 5,391
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (Giuseppe)
wtf..that is bs as far as im concerend.if it blows on the dyno in vtec...whats stopping it from blowing on the street?????? any difference...nope...infact street is probably worse.
04-22-2002, 05:24 PM
#7
Honda-Tech Member
Join Date: Jan 2000
Location: Sacramento, CA
Posts: 14,500
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (Giuseppe)
Well if you are losing boost/fuel mixture due to overlap there is some validity to what the guy is saying... but if you tune to a safe A/F ratio and aren't experiencing detonation, then there is no problem anyways.
Dustin
Dustin
Trending Topics
04-22-2002, 09:18 PM
#8
Honda-Tech Member
Join Date: May 2001
Location: Torrance, CA, USA
Posts: 420
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (Giuseppe)
If you do not want to blow it up, get it tuned properly. Tuning with out the VTEC cam and then switching it on afterwards is a good way of running exceedingly lean on the top end. Wide band AF meters work fine.
Doug
[Modified by Hondata, 10:19 PM 4/22/2002]
Doug
[Modified by Hondata, 10:19 PM 4/22/2002]
04-22-2002, 09:27 PM
#9
Join Date: Jan 2002
Location: San Diego, CA, USA
Posts: 1,762
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (Giuseppe)
ive seen a motor on the dyno blow up when VTEC hit,
the reason above was the explanation by the shop.
so this is why i ask...thanks!
the reason above was the explanation by the shop.
so this is why i ask...thanks!
04-22-2002, 10:28 PM
#10
Member
Thread Starter
Join Date: Sep 2001
Posts: 1,071
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (sushibug)
ive seen a motor on the dyno blow up when VTEC hit,
the reason above was the explanation by the shop.
so this is why i ask...thanks!
haha, maybe the shop fuxxed up his motor and made a BS story to not take the fall. if i were u i'd get it tuned somewhere else!
the reason above was the explanation by the shop.
so this is why i ask...thanks!
haha, maybe the shop fuxxed up his motor and made a BS story to not take the fall. if i were u i'd get it tuned somewhere else!
the performance shop that pulled the motor out later that week
gave that explanation...but again , after the fact.
ok then i guess its all guns GO...dyno tune with vtec working it is..
04-23-2002, 05:18 AM
#11
Honda-Tech Member
Join Date: Jan 2000
Location: TX, USA
Posts: 1,627
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (Giuseppe)
Ok... tuning w/o VTEC enabled would be lame.
First of all... you would not be getting an accurate tune. You would be tuning for the low-lift lobes on the dyno, then as soon as you go into VTEC on the street... all the dyno tuning you just did is worthless.
The overlap problem is a non-issue. Overlap with VTEC would only be a problem at low RPM. At high RPM the overlap just helps fill the cylinders. At high RPM overlap should not allow mixture to "blow thru." Non-issue.
First of all... you would not be getting an accurate tune. You would be tuning for the low-lift lobes on the dyno, then as soon as you go into VTEC on the street... all the dyno tuning you just did is worthless.
The overlap problem is a non-issue. Overlap with VTEC would only be a problem at low RPM. At high RPM the overlap just helps fill the cylinders. At high RPM overlap should not allow mixture to "blow thru." Non-issue.
04-23-2002, 12:54 PM
#12
Honda-Tech Member
Join Date: Apr 2000
Location: Toronto, ON, Canada
Posts: 996
Likes: 0
Received 0 Likes
on
0 Posts
Re: dyno tuning boosted vtec engines.....[Q] (MarkC)
This makes no sense. Blow through would give false lean readings, not false rich readings. That would mean the tuner would be running the engine richer than he should, which wouldn't be any problem.
Thread
Thread Starter
Forum
Replies
Last Post
