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Semi-Noob VEMS questions

Posted: Thu Feb 05, 2015 1:15 pm
by WI-3B-200
I'm strongly thinking about throwing this in My '91 '200TQ. I dont have some lofty goal of 1000 hp but rather switch over to Corn (E85) possibly up the boost some on the factory turbo and enjoy.

The questions I have:

-If i switch to VEMS and do an LS type Coil on plug swap, Can i get multiple sparks as I could with an MSD or similar Ignition box?

- If I wanted to have 5 EGT sensors to monitor each cylinder so i can refine injector duration/AFR per each cylinder can/does VEMS support that?

Personal experience/feeling questions:

-is switching to E85 worth/necessitate changing from the factory pump to the 044 pump? (or other instert brad here better?)

-Injector size recommendations

- Any VEMS Guru's live in WI near Green Bay to help tune if/when I change?

Is it worth spending the money to switch to VEMIS and E85 if i don't plan on running a huge turbo and upgrading the everything (yet?)

Thanks for spending the time guys I appreciate it. I know a lot of these questions have been answered in other forums and probably this one.

Re: Semi-Noob VEMS questions

Posted: Wed Feb 11, 2015 3:39 pm
by WI-3B-200
Really no one?

Re: Semi-Noob VEMS questions

Posted: Wed Feb 11, 2015 6:23 pm
by Fundahl
I know with 30% less btu content per unit than pump gasoline, your injector setup will need to flow 30% more. Ethanol evaporates very well with higher injection pressures.

Re: Semi-Noob VEMS questions

Posted: Wed Feb 11, 2015 6:24 pm
by Fundahl
30% more for the same horsepower number, and e85 being much higher octane than your 93 pump

Re: Semi-Noob VEMS questions

Posted: Wed Feb 11, 2015 6:27 pm
by Fundahl
Higher octane meaning better detonation threshold meaning you can running more aggressive tune via advanced ignition timing and more manifold pressure. Basically

Re: Semi-Noob VEMS questions

Posted: Wed Feb 11, 2015 6:50 pm
by loxxrider
WI-3B-200 wrote:I'm strongly thinking about throwing this in My '91 '200TQ. I dont have some lofty goal of 1000 hp but rather switch over to Corn (E85) possibly up the boost some on the factory turbo and enjoy.

The questions I have:

-If i switch to VEMS and do an LS type Coil on plug swap, Can i get multiple sparks as I could with an MSD or similar Ignition box?

- If I wanted to have 5 EGT sensors to monitor each cylinder so i can refine injector duration/AFR per each cylinder can/does VEMS support that?

Personal experience/feeling questions:

-is switching to E85 worth/necessitate changing from the factory pump to the 044 pump? (or other instert brad here better?)

-Injector size recommendations

- Any VEMS Guru's live in WI near Green Bay to help tune if/when I change?

Is it worth spending the money to switch to VEMIS and E85 if i don't plan on running a huge turbo and upgrading the everything (yet?)

Thanks for spending the time guys I appreciate it. I know a lot of these questions have been answered in other forums and probably this one.


Sorry, didn't see this.

My opinion is that it isn't worth switching to e85 on the stock turbo. You aren't really detonation limited with the stock turbo. You're just limited by that compressor and the stock fuel injectors. They will run out of flow at stock fuel pressure and high boost on stock turbo over about 5500 RPM. That's why most tunes taper the boost past that RPM range, it isn't because the turbo can't produce the boost up there. I found that 15 psi past 5500-6k was all the stock injectors can safely produce. By going to VEMS, you will be able to run bigger injectors. It's worth it for that alone in my opinion.

You can run multiple coils on VEMS, but not sure what you mean by multiple spark.

VEMS supports EGT sensors, but not 5 simultaneously. You'd have to get a different system (I think AEM makes one) to run that many at once. That isn't what most people do though. I have 5 EGT ports on my exhaust manifold, but it is just for them to be hot-swappable during tuning. I can understand wanting to have them all at the same time though. That will require more hardware though.

I'd swap to a different pump regardless. The stock one will do just fine, but mine seized up on me after about 20 years of service. That said, I put a used one out of a V8 into it and it has been working ever since lol. Anyway, better to be safe and just throw a new one in if you can, but make sure it is a real, OEM one or real Bosch.

Stock turbo and E85, I'd recommend a nice set of EV14s... 550s might be a little overkill, but those would be a nice running injector that would leave you plenty of headroom for upgrades later.

If you don't have any VEMS gurus close by, we're happy to help here. Just post a log and someone will help tune it. I have time here and there for that. VEMS is pretty user-friendly in my opinion, so you should pick it up quickly.

Re: Semi-Noob VEMS questions

Posted: Thu Feb 12, 2015 9:46 am
by WI-3B-200
Thanks for the info. I guess we will see what Tax-miss brings :)

Re: Semi-Noob VEMS questions

Posted: Wed Mar 04, 2015 12:32 pm
by Wilford Brimley
I'm in WI, and can help.

This wouldn't happen to be the gold one out of Milwaukee, would it?

Re: Semi-Noob VEMS questions

Posted: Mon Mar 09, 2015 11:32 am
by WI-3B-200
Nope I'm up in the Fox Cities. Funds have decided that VEMS is out for this year. For the record its Alpine White