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I regapped my sparkplugs with good results by zkhennings
Started on: 05-17-2013 01:18 AM
Replies: 50 (1403 views)
Last post by: 84fiero123 on 10-13-2013 08:29 PM
zkhennings
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Report this Post05-17-2013 01:18 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
I have an MSD Blaster coil (2.8 v6) so I wanted to play with my sparkplug gap. The gaps were all around 0.045 - .0040 inches, and I changed them to 0.060".

I had a very noticeable difference in low end torque. I have yet to compare the top end but I think it will be a little better. Big difference at low rpms though. I have no idea what will happen to longevity, but performance wise it feels good.
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Report this Post05-17-2013 09:05 AM Click Here to See the Profile for mcguiver3Send a Private Message to mcguiver3Edit/Delete MessageReply w/QuoteDirect Link to This Post
Never thought of that
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zkhennings
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Report this Post05-17-2013 09:13 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
So I tested at high RPMS (~6000) on the way to work and it feels good. There is a little difference in power up top, no miss or anything, but huge differences ~3000 rpm range, it is very easy to chirp tires into second now shifting at like 5000 rpms where before I would have to shift at 6000 to do that (not that I should be anyways with the isuzu). I am also running a compcams 260H so I am getting a higher density of fuel and air than stock so that may be part of the contribution to power. But yea very very noticeable at the low RPMs, pulls hard.

And the stock duke uses the same plugs gapped to .060" so it is not even asking too much of the plugs. Time will tell how well the cap and rotor will hold up.

[This message has been edited by zkhennings (edited 05-17-2013).]

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Joseph Upson
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Report this Post05-17-2013 01:26 PM Click Here to See the Profile for Joseph UpsonClick Here to Email Joseph UpsonSend a Private Message to Joseph UpsonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:

I have an MSD Blaster coil (2.8 v6) so I wanted to play with my sparkplug gap. The gaps were all around 0.045 - .0040 inches, and I changed them to 0.060".

I had a very noticeable difference in low end torque. I have yet to compare the top end but I think it will be a little better. Big difference at low rpms though. I have no idea what will happen to longevity, but performance wise it feels good.


I've been trying to spread that info for a while now, that without a complete aftermarket high output ignition system with all of the components, installing the HO coils alone will not offer any benefit unless you increase the plug gap to take advantage of the higher voltage rating, otherwise you will only get the voltage required to jump the gap despite how powerful the coil is.
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Patrick
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Report this Post05-17-2013 02:24 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:

I had a very noticeable difference in low end torque... performance wise it feels good.


Glad you're pleased with how your car runs, but I agree with a lot of other people who've posted here over the years that they don't notice any difference in performance with an MSD coil... and yes, that's when using the wider plug gap as well.

I've tried the MSD coil with a 2.8 and with a 2.5 (it's actually still on my '84 duke), and in my opinion the MSD coil offers nothing for engine performance that a properly functioning stock ignition system doesn't already supply.

I'm not trying to be "negative", but I just want to make it clear to anyone new here that slapping an MSD coil on their pride and joy Fiero does not guarantee a kick-in-the-pants difference in performance.
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Report this Post05-17-2013 03:02 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
I think it is a case of wishful thinking that changing the gap will get you a big boost in performance. If you think about it, all the air fuel mixture in the cylinder burns up no matter how it is lit. If it doesn't then you would see the results in a smog test. Think I may believe it if I saw a dyno test with the only change being a gap in the plugs. Not to say this does not happen, but if it does, I think what is really going on is that the larger gap is compensating for some other problem or defect. Larry
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Report this Post05-17-2013 04:39 PM Click Here to See the Profile for Joseph UpsonClick Here to Email Joseph UpsonSend a Private Message to Joseph UpsonEdit/Delete MessageReply w/QuoteDirect Link to This Post
A difference in performance associated with a plug gap change is usually a stability change as a result of the spark intensity at a given rpm. The spec plug gap matches what the vehicle was tested on, it does not mean it is the ideal gap for the full operating range of the motor anymore than the specified oil weight is the ideal viscosity for the same vehicle in every environment. It may or may not change idle quality simply because of the effect the gap change may have on igniting the fuel but as stated generally adds no power that was not already there. I heard of too many vehicle owners not necessarily noticing a gain in performance but a difference in idle quality to believe it doesn't at least have some effect, but I say go OE coils everytime.

[This message has been edited by Joseph Upson (edited 05-17-2013).]

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Report this Post05-17-2013 04:46 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
Anyone I suppose can experimant with this.
What is the problem one will run into if it is gapped too big?
Is it a problem you would notice, or would it just kill parts quietly over time?
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zkhennings
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Report this Post05-17-2013 04:58 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
My engine is brand new (1163 miles on it) as well as all sensors, no codes, and it ran perfectly well before I gapped them. NAPA gold wires, all ignition components around 1 year old (with about 2000 miles on them total). I actually kicked the tail to the side during a burnout today, that never ever happens. And yea both a normal or larger gap will cause all the mixture to burn, but rate of burn can be affected which has an impact on performance like timing does. Why would the duke's gap be bigger with the same spark plugs? I think it is related to cylinder size and amount of fuel and air in each cylinder. Now that my car is pulling more air and fuel into it with ported manifolds, heads, exhaust, and a performance cam, the increased spark energy may be benefiting me. Regardless of the power change, there have been many results reporting increased gas mileage from doing this.

Also another consideration is that because I opened up the air passages in the intakes, the velocity is going to be slower at low rpms which causes torque to suffer and fuel and air does not mix as well (slower is less turbulent which with the pintle style injectors is necessary for atomization). Like I said I do not really feel difference up top, but down low in the revs. Maybe the increased spark energy is igniting the mixture better at low rpms. O2 sensors can't sense unburned fuel, if the fuel is not atomizing as well there will be a bunch of extra fuel not burning early or clean enough. Still produces the same ratio of burned gas to oxygen, but it would burn later in the ignition stroke almost as though the timing is retarded vs when the high energy spark will ignite the mixture at a more rapid rate.

If your car is stock and your plugs are igniting the mixture fully and quickly, then there will be no noticeable improvement. Maybe an MPG or two. On the Fbody forums I was reading (before I decided to regap my plugs) how they set the best quarter mile times setting the gap higher and higher until it starts to miss, and then they back off some.

So I guess you are correct in a way, but my problem is not with the ignition system being faulty, it is with the mixing of air and fuel at low rpms being worse. My car felt slower by a lot than it used to at the low rpms, but above 3000 forget about it, it is much improved. Since doing the extra gapping, I have my bottom end performance back, and it might be a little faster down low than it used to be now.

So I guess what you are not taking into account is burn rate and how that can help performance or gas mileage on a modified car at the least.
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zkhennings
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Report this Post05-17-2013 05:01 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post

zkhennings

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quote
Originally posted by 2.5:

Anyone I suppose can experimant with this.
What is the problem one will run into if it is gapped too big?
Is it a problem you would notice, or would it just kill parts quietly over time?


You will notice, the engine will miss. Now that would be in regards to being gapped too big for the coil, you can also gap it too big for your ignition components if they have not been upgraded (cap rotor wires) and those will fail on you over time. The plugs will be fine, like stated, the duke has the same plugs gapped to .060 stock.
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Report this Post05-17-2013 05:32 PM Click Here to See the Profile for nosracSend a Private Message to nosracEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by trotterlg:

I think it is a case of wishful thinking that changing the gap will get you a big boost in performance. If youk about it, all the air fuel mixture in the cylinder burns up no matter how it is lit. If it doesn't then you would see the results in a smog test. Think I may believe it if I saw a dyno test with the only change being a gap in the plugs. Not to say this does not happen, but if it does, I think what is really going on is that the larger gap is compensating for some other problem or defect. Larry


I respectfully disagree. I went from .060 gap to .045 and lost tons of low end torque. I changed gap due to spark blowout (3800 forced induction) .
The best gap is the largest you can get without misfires.
With the .060 gap I could spin the tires and with the .045
I can barely get out my own way. So I plan on running .055-.057 to get as big as possible. The AFR amg mpg are also positively impacted.
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Report this Post05-17-2013 05:50 PM Click Here to See the Profile for JustinbartSend a Private Message to JustinbartEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by nosrac:


I respectfully disagree. I went from .060 gap to .045 and lost tons of low end torque. I changed gap due to spark blowout (3800 forced induction) .
The best gap is the largest you can get without misfires.
With the .060 gap I could spin the tires and with the .045
I can barely get out my own way. So I plan on running .055-.057 to get as big as possible. The AFR amg mpg are also positively impacted.


------------------
Turbo 3800 E85 F23 5spd spec5
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zkhennings
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Report this Post05-17-2013 06:05 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
FWIW I just did a huge (relative to having a 2.8) burnout from a stop sign on my way home from work. Probably 35 feet and actually smoked the tires which never happens. I have horrible 185s for tires but regardless there has definitely been an improvement on my car and I wanted to share.

Also many many many people have had a positive impact on MPGs, just do a google search. I cannot tell yet if I have but I will report back within a week, got to fill up the tank soon. Factory sets gap small for ignition component longevity and of course there is a safety factor in there. I read that on a car that is stock, a .010 increase is usually acceptable with no issues and an increase in MPG (nothing drastic, but quantifiable) I myself will withhold on MPG claims until I see my own results, just reporting on my research.

[This message has been edited by zkhennings (edited 05-17-2013).]

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Patrick
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Report this Post05-17-2013 06:11 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:

FWIW I just did a huge (relative to having a 2.8) burnout from a stop sign on my way home from work. Probably 35 feet and actually smoked the tires which never happens.


I suggest you return the gap of your plugs to .045" before you hurt yourself.

I dunno... seems to me that the ability to "smoke" your tires would have more to do with road conditions than plug gap.
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zkhennings
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Report this Post05-17-2013 06:18 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Haha maybe!

I am going to get new wires and cap and rotor soon. Maybe I will put the gap back to stock, check 0-60, then put it at .060 and check again. Just to make sure it is indeed not another ignition component holding me back. Can the ICM affect this as well? I have always assumed that a bad ICM would be very obvious but maybe not?

I completely understand that in a perfect world it can make no difference, but for me it did, I would like to find out why after verifying quantitatively that it does make a difference.

[This message has been edited by zkhennings (edited 05-17-2013).]

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Report this Post05-17-2013 06:21 PM Click Here to See the Profile for sleevePAPASend a Private Message to sleevePAPAEdit/Delete MessageReply w/QuoteDirect Link to This Post
only real way to confirm this is to strap it on a dyno and not mess with anything other than gap?
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zkhennings
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Report this Post05-17-2013 06:23 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yea but first it needs to be verified that all the other ignition components are working perfectly.
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Report this Post05-17-2013 06:26 PM Click Here to See the Profile for JustinbartSend a Private Message to JustinbartEdit/Delete MessageReply w/QuoteDirect Link to This Post
I've talked to one guy that did back to back dyno runs with only changing plug gap, He picked up 1% horsepower.

------------------
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zkhennings
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Report this Post05-17-2013 06:48 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yea I saw dyno test that showed that, but it was a stock newer engine. I am sure that newer engines with more advanced ports in the heads and better combustion chambers don't need help igniting their mixtures as much though, where the 2.8 is far from Ideal.
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Report this Post05-17-2013 07:24 PM Click Here to See the Profile for BlacktreeClick Here to visit Blacktree's HomePageClick Here to Email BlacktreeSend a Private Message to BlacktreeEdit/Delete MessageReply w/QuoteDirect Link to This Post
My experience with spark plug gapping was a little different. Back when my 3.4 V6 used a distributer, I tried widening the plug gap. The ignition system had all new components, plus the MSD coil and Taylor low-impedence plug wires. I found that increasing the gap to 0.050" made the engine run a little smoother. But 0.060" caused occasional misfires, and fouled up the plugs. I then tried 0.055", and the misfires went away, but plugs still fouled up a bit. So I dropped it back to 0.050".

I think the moral of the story is "your mileage may vary". Although, if you're running a wide plug gap, you may want to keep an eye out for abnormalities.

[This message has been edited by Blacktree (edited 05-17-2013).]

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Report this Post05-17-2013 07:47 PM Click Here to See the Profile for trotterlgClick Here to Email trotterlgSend a Private Message to trotterlgEdit/Delete MessageReply w/QuoteDirect Link to This Post
People on the internet report huge gains in MPG and HP by taping cow magnets to the fuel line too. Larry
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Report this Post05-17-2013 08:06 PM Click Here to See the Profile for PatrickClick Here to Email PatrickSend a Private Message to PatrickEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by trotterlg:

People on the internet report huge gains in MPG and HP by taping cow magnets to the fuel line too.


I'm not removing my cow magnets!

[This message has been edited by Patrick (edited 05-18-2013).]

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nosrac
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Report this Post05-17-2013 08:27 PM Click Here to See the Profile for nosracSend a Private Message to nosracEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Justinbart:






LOL...Don't take my word for it....Google it?

What plugs and gap for Formula's car?


http://www.ngksparkplugs.co...qpregap.asp?mode=nml
Another consideration that should be taken into account is the extent of any modifications that you may have made to the engine. As an example, when you raise compression or add forced induction (a turbo system, nitrous or supercharger kit) you must reduce the gap (about .004" for every 50 hp you add). However, when you add a high power ignition system (such as those offered by MSD, Crane, Nology) you can open the gap from .002-.005".

[This message has been edited by nosrac (edited 05-17-2013).]

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zkhennings
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Report this Post05-18-2013 11:59 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by trotterlg:

People on the internet report huge gains in MPG and HP by taping cow magnets to the fuel line too. Larry


No one has made any claims of huge gains sir
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zkhennings
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Report this Post05-19-2013 08:36 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yea smoking the tires was a fluke lol but I can still kick the tail to the side every time. My poor isuzu
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Report this Post05-19-2013 02:00 PM Click Here to See the Profile for gmctyphoon1992Click Here to Email gmctyphoon1992Send a Private Message to gmctyphoon1992Edit/Delete MessageReply w/QuoteDirect Link to This Post
also wouldnt you have to take into account that the gap on the plugs widen over time anyways....
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Report this Post05-19-2013 11:22 PM Click Here to See the Profile for AL87Click Here to Email AL87Send a Private Message to AL87Edit/Delete MessageReply w/QuoteDirect Link to This Post
you could also modify the ground electrode (by cutting the overhanging part of it off) like what some people used to do to get the combustion kernel to fire out and directly towards the piston top, instead of out from in between the electrodes first and then towards the piston top.

[This message has been edited by AL87 (edited 05-19-2013).]

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Report this Post05-21-2013 10:00 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
I suppose what octane you run and what timing you have would affect this test as well.
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Report this Post05-21-2013 11:40 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
10* and 87 octane, stock 8.5:1 compression. Duke is 9.5:1? Mine always ran better with premium and got way better gas mileage
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Report this Post05-21-2013 12:07 PM Click Here to See the Profile for carbonSend a Private Message to carbonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:

10* and 87 octane, stock 8.5:1 compression. Duke is 9.5:1? Mine always ran better with premium and got way better gas mileage


L44 HO was always 8.9:1

8.5:1 was for the 110HP version of the 2.8
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zkhennings
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Report this Post05-21-2013 01:23 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Are you sure? I have always been under the impression that only the 88s had 8.9:1 but I would be happy if we all had 8.5:1
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Report this Post05-21-2013 02:24 PM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
All Fiero 2.8s are H.O.
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carbon
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Report this Post05-21-2013 02:28 PM Click Here to See the Profile for carbonSend a Private Message to carbonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:

Are you sure? I have always been under the impression that only the 88s had 8.9:1 but I would be happy if we all had 8.5:1


Only the 88s are internally balanced...
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Report this Post05-21-2013 03:55 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
I know they are all HO and I know the 88s are internally balanced.

http://floridafieros.org/osg/60-degree-V6.html

This is not where I got my information originally, I think it is the power manual, but I mistook where it says 8.5:1 - 8.9:1 for 85-88 and then 87 is 8.9:1 as meaning that the earlier engines were 8.5:1. I did not realize it was referring to a change with the gen 2 engines. I guess they can vary from production variance? I have seen 8.5:1 frequently as the stock compression ratio.
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Report this Post05-21-2013 04:03 PM Click Here to See the Profile for carbonSend a Private Message to carbonEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by zkhennings:

I know they are all HO and I know the 88s are internally balanced.

http://floridafieros.org/osg/60-degree-V6.html

This is not where I got my information originally, I think it is the power manual, but I mistook where it says 8.5:1 - 8.9:1 for 85-88 and then 87 is 8.9:1 as meaning that the earlier engines were 8.5:1. I did not realize it was referring to a change with the gen 2 engines. I guess they can vary from production variance? I have seen 8.5:1 frequently as the stock compression ratio.


Regardless, all Fiero 2.8s are L44 RPO code engines and have an 8.9:1 compression ratio.

[This message has been edited by carbon (edited 05-21-2013).]

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Report this Post05-22-2013 12:07 AM Click Here to See the Profile for skuzzbomerSend a Private Message to skuzzbomerEdit/Delete MessageReply w/QuoteDirect Link to This Post
For what it's worth, I gained 1mpg when I went to an MSD coil... but I later gained 2mpg from a new distributor and plugs so, obviously, your mileage may vary.
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Report this Post05-22-2013 10:36 AM Click Here to See the Profile for 2.5Send a Private Message to 2.5Edit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by skuzzbomer:

For what it's worth, I gained 1mpg when I went to an MSD coil... but I later gained 2mpg from a new distributor and plugs so, obviously, your mileage may vary.


Or maybe it could be said, you had lost those mpgs previously?
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zkhennings
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Report this Post05-22-2013 11:19 AM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
Yes those mpgs had been lost previously if the gap stayed the same. The energy from a msd vs stock is the same if the gap is the same, so the higher output coil was just making up for old wires and maybe dirty plugs. Gapping higher with MSD gives higher energy spark. Higher energy spark helps burn the mixture faster and more fully is the theory. This can aid with gas mileage because gas is not being wasted as more is being burned than with stock spark energy.
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Report this Post05-22-2013 04:10 PM Click Here to See the Profile for Old LarSend a Private Message to Old LarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Split fire plugs is the way to go .
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Report this Post05-22-2013 04:27 PM Click Here to See the Profile for zkhenningsSend a Private Message to zkhenningsEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by carbon:


Regardless, all Fiero 2.8s are L44 RPO code engines and have an 8.9:1 compression ratio.



In many places you can find that the L44 is a range from 8.5:1 - 8.9:1

Here is a book about pontiac and it says the fiero L44 engine had 8.5:1 compression ratio. I have seen both numbers in a lot of places for the L44. So I am guessing that the combustion chambers, being cast had some variance resulting in a range from 8.5:1 - 8.9:1.

I honestly do not care and have never actually done a volumetric compression ratio test, but that is what the literature says. Just so we are clear I am not arguing about my original statement, I understand the 85-88 were all intended to have the same compression ratio.
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