Ignition and e85

[turbodaniel]

I see all the mods that are required to run e85 but not much info or discussion on ignition mods

30 percent more fuel.. stock ignition?????

 

[we4Mateo]

Yep. Cylinder pressure is cylinder pressure and directly related more to hp than fuel volume. If it blows out the spark on race gas, it'll do the same on e85 regardless of the extra fuel volume.

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[we4Mateo]

I personally think a tr6 ignition is needed at anything approaching 400rwhp.

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[forcefed3.8's]

Yep. Cylinder pressure is cylinder pressure and directly related more to hp than fuel volume. If it blows out the spark on race gas, it'll do the same on e85 regardless of the extra fuel volume.

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Not true. E85 doesn't like to fire as it is, add 30% more and it takes a strong spark. I think Dan saw it on the dyno.

 

[TT/Ameasap]

I just went through this. I raced my car on 93/alky and did my swap to E85. It broke up at same boost level as 93/alky. I thought my coilpack/ignition was bad, but ended up being gap was too large for E85. I reduced gap to .024 and it went away. Now I have a volt booster and in the process of regapping my plugs (larger) for better fuel mileage.
So, Yes....You need to do some changes..Whether it be plugs,volt booster ect.

BTW, This is an excellent question.

 

[we4Mateo]

I just went through this. I raced my car on 93/alky and did my swap to E85. It broke up at same boost level as 93/alky. I thought my coilpack/ignition was bad, but ended up being gap was too large for E85. I reduced gap to .024 and it went away. Now I have a volt booster and in the process of regapping my plugs (larger) for better fuel mileage.
So, Yes....You need to do some changes..Whether it be plugs,volt booster ect.

BTW, This is an excellent question.

Thanks for the info. All the more reason to stop using stock ignition systems beyond their intended horsepower range and fuel type.

 

[turbodaniel]

Yep. Cylinder pressure is cylinder pressure and directly related more to hp than fuel volume. If it blows out the spark on race gas, it'll do the same on e85 regardless of the extra fuel volume.

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I agree cylinder pressure is cylinder pressure but the dynamics to create that pressure have to change dramatically imo... adding 30 percent more of a fuel that is harder to ignite has to really limit a stock ignition system... which I found out, at least on my car that after 16lbs. of boost I was done

 

[we4Mateo]

I'd also argue that this issues are coming up when switching because of the marginal power of our ignition systems. I'd bet that on a FAST XFI car w/ LS ignition setup, that there would be few changes outside of gapping.

 

[we4Mateo]

I agree cylinder pressure is cylinder pressure but the dynamics to create that pressure have to change dramatically imo... adding 30 percent more of a fuel that is harder to ignite has to really limit a stock ignition system... which I found out, at least on my car that after 16lbs. of boost I was done

Also good info. Thank you.

 

[Flyin Brian]

A stock ignition system in good shape will go far with good wires and a volt booster. I am running 24 psi boost with no problems lighting it off. I have a new stock coil, new stock module, Magnecore plug wires, volt booster, and plugs gapped at .032". My E85 only tests at E65 so that probably helps. I do plan on switching to the TR6 someday to see if I can open the gap up a little.

 

[Nick Micale]

I agree cylinder pressure is cylinder pressure but the dynamics to create that pressure have to change dramatically imo... adding 30 percent more of a fuel that is harder to ignite has to really limit a stock ignition system... which I found out, at least on my car that after 16lbs. of boost I was done

In my experience I think you and Matt are right-on with your comments and conclusions and we have been dealing with this on e-85 performance applications for a couple years with limited success.

It is ironic that just this AM, a test drive in a car we have been fighting high RPM and boost issues for a year and a half, it has proved to my satisfaction just what you both, and others, have stated!

The car is a turbo T with a 270 cu.in 4.1 with TA alum heads and a TE-45A turbo. It would pull like crazy to 10 psi, then break up. We installed a new $300 module and coil and it then went to 12 psi. I dug out an original 1987 module/coil and it then got to 15 psi.

Today with the TR6 even at 20 psi on the interstate at 100+ MPH, it was still pulling strong!

Last year I converted my race car from 116 octane to e-85 and never had this issue, BUT it uses a distributor with a MSD 4AL which puts out LOTS of spark.

The many other local e-85 conversions we have done are street cars and are not at the 500-600 HP level, so we have not had this problem for the reasons mentioned of cylinder pressure, and the larger amount of e-85 fuel injected needed for the additional HP.

When this issue first came up last year, we tried 1/2 dozen stock module/coil units, and then 3 or so new ones which made this very frustrating as they would not perform?

We also tried other parts like new crank and cam sensors, new harness, injectors with no avail?

A conversation with John Spina of Casper's last week was very enlightening as he pointed out the new modules cannot be produced exactly like the originals because many original components are no longer available, so substitutions are made.

The new units work OK on the street cars, but modified higher HP demands are usually not met with them?

Fortunately the turbo Buick community has people like Bob Bailey to provide us with products like the TR6 that far surpasses what the factory parts could do in their day.

 

[turbodaniel]

Interested in how the TR6 and a MSD DIS-4 would perform at higher boost levels...say 30psi

 

[forcefed3.8's]

A stock ignition system in good shape will go far with good wires and a volt booster. I am running 24 psi boost with no problems lighting it off. I have a new stock coil, new stock module, Magnecore plug wires, volt booster, and plugs gapped at .032". My E85 only tests at E65 so that probably helps. I do plan on switching to the TR6 someday to see if I can open the gap up a little.

You also have to consider the power level. The more power you make, the rules change. Octane requirement vs. boost, plug gap, timing, target AFR all change from say an 11 sec car to an 8 sec car. Even plug heat ranges need to be considered.

 

[Flyin Brian]

That's true. My car is only around 11's in the quarter mile.

 

[forcefed3.8's]

That's true. My car is only around 11's in the quarter mile.

You have an easy 10 sec combo.
I was interested to see the limits of the stock ignition on E85 in a 9 sec car. On my car with a distributor and a Crane ignition, I had to close the gap up to .015 with E85, and ran at .023 with gas. Never had a problem on gas. Even with the gap so tight on E85, it was still at its limit at 24psi, I ran 26psi on gas. Now I am running an MSD 7AL and have the gap at .025".

 

[Flyin Brian]

My goal is to get into the 10's this year. Have not been to the track since I got the bigger turbo and the right converter. I guess I will find the limit of the stock ignition at some point but probably not until I am able to crank the boost up to 28-30 psi where the turbo wants to run.

 

[forcefed3.8's]

What turbo is it? You might be surprised. That engine might take everything it has in the mid 20's.

 

[we4Mateo]

Interested in how the TR6 and a MSD DIS-4 would perform at higher boost levels...say 30psi

I've ran "all the boost" on my TE44, just south of 30psi, and the TR6 lit it off proper even on a .040 gap. NGK UR5's and stock Silverado 4.3L wires and coil pack.

 

[HighPSI]

Both the distributor (with the correct coil & Ignition box) and my CNP have seen over 40 psi on E85 without any issues. They both require an aftermarket ecu to work. One advantage to using them is, you can use all the rev limters (2 step, 3 step, high end rev limit, traction control rev limt, etc...) that the ecu will support

 

[Flyin Brian]

What turbo is it? You might be surprised. That engine might take everything it has in the mid 20's.

It is a Garrett that Bison re-built and modified for me. 62 mm compressor and a 65 mm exhaust turbine, journal bearing. .63 A/R. It had a 58 mm compressor before. The 62 mm shot up to 30 psi quick when I first put it on. That was with a super loose converter. I had to enlarge the exhaust housing hole to nearly 1.2" and put the smallest spring in my external gate just to get it to settle down to 24 psi boost which is where I am running out of injector at. The motor does seem to swallow a lot of air. I have a ton of work in the heads. Intercooler seems to be working very well too. I need to get it to the track soon and see what it will run at 24 psi boost.