Hot start and very black exhaust tip

[NitrousG35]

I just had some IPS K2 cams installed along with ID 1000 cc injectors. After having these things installed, I am having a difficult time starting my car after it is warmed up. When cold, it is fine, but when hot, it takes about 5 seconds of cranking to get it started. My tuner says he needs to change something with the fuel trim.

I read a thread here about hard starting and the advice was to "You need to change the cranking fuel compensation. Try decreasing the fuel in 10% intervals until the engine becomes more difficult to start, then increasing the fuel until it has too much, then set the cranking fuel in the middle." Would this same procedure work for a hot or warm motor?

My second question has to do with the A/F ratio. My tuner has it about 12.8 to 13.1. My tailpipe is sooty black each time I go out and drive the car, even with driving on the freeway. I had a friend of mine with me when I picked up the car who is somewhat savvy with Ford motors. He said the reading was too rich. My tuner said that this was a safe reading to prevent blowing up the motor. [As an aside, when I got the car home, the muffler was covered with black soot as a tube was used to vent the exhaust].

Is this a good A/F ratio and if not, what should the desirable reading be? My tuner has a lot of expertise with K motors and K-Pro. He has used FlashPro a number of times and says it is similar in procedure. I am just looking for anything that can assist him in perfecting the tune.

[taylorsSI]

12.8-13.1 is the correct AF ratio for WOT driving. what's it set up for part throttle/cruising? I had an extremely "sooty" exhaust and we found out that i was dipping into a very rich (11ish) afr around 2-2250 rpms on my tune. wasn't caught for a while because my tuner kept doing wot runs and seeing the afr was fine. after fixing that, it was just fine.

how do the ips cams feel?

[NitrousG35]

Thanks. I will check on the part throttle/cruising AFR. Cams perform really well. I do have another problem though, not related to the cams or tune. I have a Vibrant RH w/hfc. The cat stank up the joint, so bad that the tuner had to run a tube outside the shop to remove the smell. Car smells really nasty now, but never did before.

My tuner feels the cat has gone out and also that the design of the header is not good for making power. I am looking at a Go-Power custom header with 3" collector and a Full Race 3" exhaust to get the most out of the cams. I may go with a ported intake manifold and 2010 TL TB that is 80mm.

[taylorsSI]

not sure if this is of any help. previously I had the vibrant header with HFC on my SI, and my tuner told me it was holding me back. doing a full tune, he found the lowest he could get my vtec engagement was 3900 before it lost power (a sign of how well or poor the motor breaths). I switched to the kiddracing header and that alone allowed him to lower my vtec to 3400. so 500 rpm earlier engagement of vtec with a simple header swap. header was really cheap as well, and performs exceptionally

[OrdnanceMarine]

not sure if this is of any help. previously I had the vibrant header with HFC on my SI, and my tuner told me it was holding me back. doing a full tune, he found the lowest he could get my vtec engagement was 3900 before it lost power (a sign of how well or poor the motor breaths). I switched to the kiddracing header and that alone allowed him to lower my vtec to 3400. so 500 rpm earlier engagement of vtec with a simple header swap. header was really cheap as well, and performs exceptionally

I think your tuner must have a bias against the Vibrant because my Vibrant header with HFC couldn't have been holding me back (knowing I'm losing a little bit to the HFC). 242 HP and 177 lbft at Church Automotive with Daniel Butler tuning it. My best VTEC crossover was at 2900 RPM. AEM "V2" CAI, TBS, IMG, Vibrant Header and Exhaust. 100% stock internals on Costco 91 octane California winter gasoline. I have found that tuners tend to favor certain parts over others without a whole lot of experience with various parts and perhaps this is the case here.

[OrdnanceMarine]

Thanks. I will check on the part throttle/cruising AFR. Cams perform really well. I do have another problem though, not related to the cams or tune. I have a Vibrant RH w/hfc. The cat stank up the joint, so bad that the tuner had to run a tube outside the shop to remove the smell. Car smells really nasty now, but never did before.

My tuner feels the cat has gone out and also that the design of the header is not good for making power. I am looking at a Go-Power custom header with 3" collector and a Full Race 3" exhaust to get the most out of the cams. I may go with a ported intake manifold and 2010 TL TB that is 80mm.

Bill, you probably burned up your cat buy running it so rich. Your cat was trying to handle all of the extra fuel your engine was dumping on it and coupled with the fact that you're pushing more air through the engine with your modified valvetrain and you probably just asked too much from that little HFC cat. While I think the Vibrant is a great header, you are going quite a bit beyond stock and probably need to step up to that 3" setup you mention.

[taylorsSI]

not sure if this is of any help. previously I had the vibrant header with HFC on my SI, and my tuner told me it was holding me back. doing a full tune, he found the lowest he could get my vtec engagement was 3900 before it lost power (a sign of how well or poor the motor breaths). I switched to the kiddracing header and that alone allowed him to lower my vtec to 3400. so 500 rpm earlier engagement of vtec with a simple header swap. header was really cheap as well, and performs exceptionally

I think your tuner must have a bias against the Vibrant because my Vibrant header with HFC couldn't have been holding me back (knowing I'm losing a little bit to the HFC). 242 HP and 177 lbft at Church Automotive with Daniel Butler tuning it. My best VTEC crossover was at 2900 RPM. AEM "V2" CAI, TBS, IMG, Vibrant Header and Exhaust. 100% stock internals on Costco 91 octane California winter gasoline. I have found that tuners tend to favor certain parts over others without a whole lot of experience with various parts and perhaps this is the case here.

I dont think so. my tuner looked at the header and said the design was holding it back (he thought). i went out and purchased the kidd racing header without any advice from the tuner, and he found he was able to get my vtec lowered several hundred rpms afterward.

[OrdnanceMarine]

not sure if this is of any help. previously I had the vibrant header with HFC on my SI, and my tuner told me it was holding me back. doing a full tune, he found the lowest he could get my vtec engagement was 3900 before it lost power (a sign of how well or poor the motor breaths). I switched to the kiddracing header and that alone allowed him to lower my vtec to 3400. so 500 rpm earlier engagement of vtec with a simple header swap. header was really cheap as well, and performs exceptionally

I think your tuner must have a bias against the Vibrant because my Vibrant header with HFC couldn't have been holding me back (knowing I'm losing a little bit to the HFC). 242 HP and 177 lbft at Church Automotive with Daniel Butler tuning it. My best VTEC crossover was at 2900 RPM. AEM "V2" CAI, TBS, IMG, Vibrant Header and Exhaust. 100% stock internals on Costco 91 octane California winter gasoline. I have found that tuners tend to favor certain parts over others without a whole lot of experience with various parts and perhaps this is the case here.

I dont think so. my tuner looked at the header and said the design was holding it back (he thought). i went out and purchased the kidd racing header without any advice from the tuner, and he found he was able to get my vtec lowered several hundred rpms afterward.

Would you mind posting your dyno plots from each of the runs? Also, what other mods do you have? Honestly, I'm curious as my crossover is now 2900 RPM with great results. Notice the very small dip at 2900 RPM vs. the huge dip at 4750 that the baseline tune has. Here's my plots with one of the base MAP tunes with a 4750 RPM crossover against my final tune:

[taylorsSI]

do you have the vibrant header with the hfc? that's the one i'm talking about. my tuner said he felt that the design of the header, coupled with the hfc, is what held me back. i don't have any dyno runs, just my tunes.

dont u find 2900 far too low for vtec? i had mine at 3300 with another tune and my fuel economy sucked. kept hitting vtec without trying to, even cruising.

[OrdnanceMarine]

do you have the vibrant header with the hfc? that's the one i'm talking about. my tuner said he felt that the design of the header, coupled with the hfc, is what held me back. i don't have any dyno runs, just my tunes.

dont u find 2900 far too low for vtec? i had mine at 3300 with another tune and my fuel economy sucked. kept hitting vtec without trying to, even cruising.

I've had the Vibrant with HFC for over two years now. The HFC definitely should be cutting your gains over the ... version since it, by definition, is causing some additional backpressure (I remember Vibrant's rep stating that it should be something in the 5-7 HP range) but for those of us who are reluctant to run totally ..., it's the best alternative I could find.

As far as whether 2900 RPM is too low? It's where dyno tuning showed the best gains and the smoothest transition. The way you avoid kicking over to the high cam in regular traffic is by setting the "VTEC window pressure" to only allow engagement under high MAP at those lower RPMs. It would take a MAP of about .930 Bar to kick over at 2900 RPM but only .850 Bar at 4500 RPM. It sounds like you could use some tuning in that department.

Properly tuned you shouldn't see any real reduction in MPG as a result of your full-throttle tuning since you're only going to be there when you're in open-loop (high MAP). The rest of the time you are in closed-loop and subject to the fueling that your O2 sensor tells the ECU is best (lambda ~1).

[OrdnanceMarine]

One more note: If I had it to do all over again, I'd buy whichever header I decided would work best for me and then build up a Vibrant HFC of corresponding diameter and a test pipe. Then I could run the HFC when I wanted to (most of the time) but still be able to switch over to no HFC for tuning and track time. This would also keep me from burning up the HFC in situations like NitrousG35 experienced.

[taylorsSI]

do you have the vibrant header with the hfc? that's the one i'm talking about. my tuner said he felt that the design of the header, coupled with the hfc, is what held me back. i don't have any dyno runs, just my tunes.

dont u find 2900 far too low for vtec? i had mine at 3300 with another tune and my fuel economy sucked. kept hitting vtec without trying to, even cruising.

I've had the Vibrant with HFC for over two years now. The HFC definitely should be cutting your gains over the ... version since it, by definition, is causing some additional backpressure (I remember Vibrant's rep stating that it should be something in the 5-7 HP range) but for those of us who are reluctant to run totally ..., it's the best alternative I could find.

As far as whether 2900 RPM is too low? It's where dyno tuning showed the best gains and the smoothest transition. The way you avoid kicking over to the high cam in regular traffic is by setting the "VTEC window pressure" to only allow engagement under high MAP at those lower RPMs. It would take a MAP of about .930 Bar to kick over at 2900 RPM but only .850 Bar at 4500 RPM. It sounds like you could use some tuning in that department.

Properly tuned you shouldn't see any real reduction in MPG as a result of your full-throttle tuning since you're only going to be there when you're in open-loop (high MAP). The rest of the time you are in closed-loop and subject to the fueling that your O2 sensor tells the ECU is best (lambda ~1).

I see what you're saying. my problem with having the vtec window low is because no matter how high my tuner set the pressure for the vtec window, i was constantly going into it accidentally. often i would try and speed up a little quicker than normal and cross the threshold. had really awful mpgs until i raised it.

[all-black]

well back to nitrousg35s questions........your afr should be fine for wot as stated check how your partial throttle is do some slow pergressive slow pulls. i say this because if you stab the throttle there are tip in and tip out fuelng that you will see in the datalog that will be false. to just cruse in third somewhere around 2000... and do slow pulls light throttle keep the throttle consistent once you press it. this will help to give you the best readings. datalog and then after go through ur datalog and see how much fuel correction is going on with the lambda overlay.

also the whole vtec cross over. the cross over isnt about getting vtec as low as possible. its about the setup and the header has a lot to do with it how the cams will make power.

best header to date skunk2 that i have tested. it has out performed my ssr and go-power but i am running a k24 so the breathing of the engine is different.

when you smell the cat its time to change it. it will get plugged up and wont flow as well causing it to heat up even more and melt inside

btw nitrous this is 24ftw. nice to see you go your cams in hope your enjoying them

OrdnanceMarine you had daniel tune your car at church? what cams are you running?

[OrdnanceMarine]

OrdnanceMarine you had daniel tune your car at church? what cams are you running?

Stock cams. No plans to change them at this point.

[all-black]

this seems really weird your numbers are almost as high as bboy burst and he is running the ips k2 and you have stock cams making about the same power. not only that you guys are tuned by the same person on the same dyno seems kinda funny.