Is it worth buying a VPC????

[Maglin]

It seams us DSMer's want it easy or want it free.

Now that's the freaking truth. Their isn't to many cars out their that you can buy for $2K and stick $1K into and get 280-300 HP at the wheels. Being so darn cheap I find so many people want to go the super cheap route. New things is cool. But back yard stuff that usually ends up with something breaking just give the DSM a really bad name. IE.... the name they pretty much have now. I know lot's of people that call them completely unreliable.

 

[dsm-onster]

Now that's the freaking truth. Their isn't to many cars out their that you can buy for $2K and stick $1K into and get 280-300 HP at the wheels. Being so darn cheap I find so many people want to go the super cheap route. New things is cool. But back yard stuff that usually ends up with something breaking just give the DSM a really bad name. IE.... the name they pretty much have now. I know lot's of people that call them completely unreliable.

Oh he!! that is so true. . . Let me tell you that my 190K mile block has had 30 psi running through it for 3+ years now, DD. My tranny is NOT as weak as everyone elses tranny which seam to have clutch problems instead and blame the tranny. And the clutch problems can all too often be traced to simple install errors.

I tell guys to look at it this way. . .Yes you've saved alot of cash by deciding to get a DSM. They can be had for cheap you already have the advantage. You will already spend less than the next guy in line at the track. Don't cheap out on the mods. He hasn't. Be a conciencious consumer. But don't get that big FMIC then go to home depot and buy rubber drain couplers and wormclamps to keep the piping togetherWTF .

The other end of the spectrum are guys that decide to give all their money away so that all they have to do is jump in the car start it, hit the track, and eak out an 11se ET. You can't bolt on an 11 sec time slip. MAYBE a 12. I fell for the ease of DSMLink. DSMap wasn't out then. I surely would have gone this route if I had seen it then. I wasn't PATIENT. But I already have the link. I love it. It is pretty much plug-and-play. I'm going to get the most out of it. . .and will be happy. I can't say that a piggyback can make me or my setup happy.

Nevertheless, there's always something better for a good price that's coming out soon. BB turbos are coming down in price. And soon they'll be rebuildable. I guarantee it. Everything comes full circle. VPC, SAFC, MAFT, EMS, DSMLink, DSMap, who's next. . .

 

[Maglin]

Everything comes full circle. VPC, SAFC, MAFT, EMS, DSMLink, DSMap, who's next. . .

MegaSquirt. Very powerful and affordable stand alone EMS.

 

[JrCRXHF]

MegaSquirt. Very powerful and affordable stand alone EMS.

Yeah i have been watching that too the only problem is they are just now working on using the CAS for the trigger so i will have to wait and see. What i want is something i don't have to rip into the factor harness and i can put the car back if i decide to go another way so dsmap seems pretty good but it will not do the flex fuel sensor that megasquirt is working on.

So i have not found the system that i like the best yet.

 

[dsm-onster]

See! us DSMer's want it easy. . .

Well, they sell harness adapters for ford EEC IV & V and for Nissan and others. So I'm sure when they get the cas thing worked out, there will be reason enough to make it more plug & play. . .

 

[Maglin]

Well their really isn't anything to work out with the CAS. The MSIIextra alpha is working great on the DSM CAS. MSnSextra has been working great for over a year now with the DSM CAS. It's not something new. MSIIextra is new.

And this flex fuel stuff is just pointless. I'm not to sure what you are looking for. It cost's about the same if not a tad more to run E85 currently. In the future after the government subsidy is gone E85 will cost more than unleaded fuel. Being that at cruise speeds you will consume 15-20% more fuel over unleaded it's not any cheaper. If you are going for a cheaper high octane fuel then don't bother running unleaded at all and tune the car for E85. I ran E85 with the stock EPROM for some time. Worked great of course. Just had to tune it for E85 and went more aggressive with the AFR and timing. Don't have dyno numbers but the butt dyno said it was definitely a lot faster.

And as far as harness adapters go I wouldn't hold your breath. The EEC-IV and V Fords all use the same pin out so they are afordable to mas produce. Their are tons of them on the planet. The DSM would need 2 for the 1G and 2G. Being it isn't really in other cars that would look into a MS I would just not worry about it. IF you want to be able to run the stock computer you just splice into the main harness. You have to solder it of course but it will allow you to remove the MS unit and put the stock PCM back in. It's how I'm installing the 2 I have.

 

[dsm-onster]

Great stuff about e-85. Focus is on volvo. But, the general info is great. Like. . .

. . .When driving purely on E85 you can blend it with up to 25% gasoline in case you want to raise the AFR number used to produce max. power. In that case you can raise the boost even further since the volume of fuel needed to reach the desired lambda is decreased.


Performance application and fuel needed:

Performance application:
Let´s pretend for a while that the ECU´s in our cars are pretty good at their jobs. On gasoline it will try to keep an AFR of 14.7 (lambda=1) all the time at idle, cruise and light load. It will also try to keep a good AFR at WOT/boost of 13.2-12.5, sometimes even lower than that, probably closer to 11.x.

Why? Because the fuel has a cooling effect on the intake charge and the space in which the combustion occurs.

As you can see from the table shown above this section, the ideal target AFR´s under boost for both gasoline and E85 are listed. For gasoline it´s 13.23-12.5, and for E85 it´s 8.47-6.975. However, with E85 you will not need to richen the mixture under WOT/boost as far as 6.975 or beyond. It does not need to be proportionally richer when compared to gasoline.

Why? Again, Because the fuel has a cooling effect on the intake charge and the space in which the combustion occurs. And at such a low AFR as 9.765 (lambda=1 on E85) or lower the fuel cools pretty good, don´t you think so?

Many people with some experience in mapping an ECU for use with E85 says that as high AFR as 8.5 or lambda=0.80-0.85 works well. No need to go to the extreme end of the useable scale to get safe power. It only uses a lot of fuel without giving any benefits.

Since you don´t have to richen the mixture as many percent (proportionally) as you have to on gasoline, you can make more power without having to use as much fuel. Instead you can keep the AFR´s leaner across the board and by doing so you can make room for higher boost without maxing out the injectors.

And. . .

Since E85 is more knock-resistent you can modify your engine to make better use of the properties of the fuel and thereby gain both power and mileage at the same time. You can benefit from:
* Advancing the timing (statically or dynamically).
* Raising the compression ratio by milling the head down.
* Still maintain a high boost level in conjuction with high CR.
* In some cases you can run a slightly leaner mixture under part-load or WOT that will benefit the mileage and give head-room for more boost.

* If you have an aftermarket EMS you can get a lot out of E85 with careful mapping.
* For those of you that have looked in to Somender Singh´s groove theory, this may be very interesting for you (think: 12:1 CR, very advanced timing and high boost...).

Yes tuning the timing and fuel curves CORRECTLY for e-85 still leads to around 30% more fuel consumption in closed loop operation. Open loop: the ability to increase compression, timing (correctly), cooling of the combustion chamber, and not needing to go below 8:1 a/f ratio; all lead to more efficient extraction of power from e-85 so fuel consumption at open loop is hardly different when comparing at the same hp level.

105 octane race fuel is WAY! more expensive than e-85 gov't subsidized or not. . . E-85 is around 105 octane. And cools better.

wow! We've gone from VPCs to e-85

 

[Maglin]

Yeah.. Sorry I helped the topic to stray. E-85 is another topic altogether. But Unless you are looking to use it as a race fuel you are not going to save any money using it in your DD.

So what did you get the VPC? If so is it installed yet? Let us know what you think of it if you get it. It's funny as just 3 years ago they still sold for up to $300. Now if you can find one they are cheap.

 

[twinturbo3k]

I run a vpc/gcc combo. They are outdated yes, but much better than a GM maf setup and easy to use. 80 dollars is an insane deal, buy it install it, and run it.

 

[spinz4]

Go with a VPC you will like it. This coming from a DSMlink owner. By the way I just sold my old one for 400.00. You just have to find the right buyer

 

[Steve93Talon]

We ran a VPC/GCC setup with a Keydiver chip set up for the VPC(with it's 550 chip) and 780s. The car went 11.02 @ 126.79. With the Keydiver chip, all of the driveability problems associated with the VPC disappeared.

We later went to to DSMlink w/EVO MAF and haven't gotten the car any faster yet. Driveability also got worse, when you get off the gas from over 3k the car will stall. It seems that the compressor is backflowing through the MAF causing a rich spike. There's a large thread on DSMlink about this issue, V3 will have a decel/idle setting to fix this.

Bottom line, DSMlink is an amazing piece of equipment, but it's not perfect and it's not right for everyone. If you know how to tune, a VPC can still get you very far. For $80, if you don't buy it send it my way.

 

[1LE]

I loved my VPC/GCC setup for sheer power. Did NOT like the stumble on tip-in that would never go away. Did NOT like the on/off switch/poor driveability characteristics. Also did NOT like having to adjust my BISS every time the weather changed.

Just had the VPC removed and a 2g MAF/AFC installed. Car is a zillion times more driveable with the MAF/AFC, but has lost a very noticeable amount of top-end (but feels stronger at the bottom end). Used to keep pulling harder and harder right into the 8k limiter (GForce ECU), now it starts dropping off at 6500.

Oh well, suits my needs better with the AFC... Car was unusable in rallycross due to the accelerator being more of an on/off switch with the VPC Push a little, ummm, OK, we're kinda moving, push harder and WHAM we're spinning all 4 wheels all of a sudden... Now the response is very linear, albeit with a lot less available power on the topend.

For power, hard to compare *exactly*, but I have the following numbers to give *some* kind of idea...

Engine built and run on engine dyno with VPC hooked up, 400hp crank hp @18psi boost, but no car around it supposedly (I wasn't there). Now, MAF+AFC, put down 270hp (274ft-lb) on a Mustang dyno @20psi (same engine/turbo/ic, etc.). So, I'd guess I gave up something like 50hp, but went from a dyno/track queen to a real streetable machine that will probably go just as fast in the 1/4...

Oh, anyone want to buy a slightly used VPC? ;-) ;-)

 

[dsm-onster]

Just had the VPC removed and a 2g MAF/AFC installed. Car is a zillion times more driveable with the MAF/AFC, but has lost a very noticeable amount of top-end (but feels stronger at the bottom end). Used to keep pulling harder and harder right into the 8k limiter (GForce ECU), now it starts dropping off at 6500.

Sorry man. I don't believe for ine second that your setup pulled to 8K w/ stock cams. . .


It really looks like the SAFC is not tuned properly. There's no way going from one tuning device to the next will net you such a loss. . . 400 crank? 270 wheel? nope. Somebody TOLD you a story or your SAFC is out of tune. . .

 

[1LE]

Sorry man. I don't believe for ine second that your setup pulled to 8K w/ stock cams. . .


It really looks like the SAFC is not tuned properly. There's no way going from one tuning device to the next will net you such a loss. . . 400 crank? 270 wheel? nope. Somebody TOLD you a story or your SAFC is out of tune. . .

You're quite right. I *don't* have stock cams. It's a built high compression motor with ported everything and HKS cams... Also note that it's not as simple as going "from one tuning device to another"... The VPC is a whole lot more than just a tuning device. It gets rid of the MAF and gives you a big gaping hole for air to flow through

I know that the car definitely has a lot less top-end with the SAFC. The SAFC was dyno-tuned to AFR. The last time I re-tuned the VPC (after replacing a failed FPR), I just tuned for best timing, and it ended up feeling the same as when I bought it (already built up and ready to go). Either way, the power definitely drops off instead of picking up at the top end now. Mid-range feels very similar, perhaps a little better. Bottom end is a WHOLE lot stronger with the AFC/MAF combo.

I intend on doing some pulls myself with my datalogger this summer and try tuning for best timing (assuming my results will be different from tuning for AFR) to see if I can gain/lose any power. However, I doubt it will be much different. I have a local friend with almost the exact same setup I have now, and our cars NOW feel very similar. My car
*used* to have a ton more top-end...

I'll update on how it goes if you'd like. I'd sure like to recover that top-end AND keep the low to mid power!

 

[GVR4592]

You aren't going to lose a lot of top end from adding a maf in front of the turbo. It's most likely a tuning issue.

 

[spinz4]

Sorry man. I don't believe for ine second that your setup pulled to 8K w/ stock cams. . .


It really looks like the SAFC is not tuned properly. There's no way going from one tuning device to the next will net you such a loss. . . 400 crank? 270 wheel? nope. Somebody TOLD you a story or your SAFC is out of tune. . .

I have pulled to 8k with stock cams....Why is that so unbelievable?

 

[dsm-onster]

I have pulled to 8k with stock cams....Why is that so unbelievable?

Hurling your tach needle to 8K w/ stock cams and recording higher airflow numbers w/ said stock cams at 8K are two totally different things.

 

[dsm-onster]

You aren't going to lose a lot of top end from adding a maf in front of the turbo. It's most likely a tuning issue.

I agree wholeheartedly!

 

[Maglin]

chances are that the VPC was just going into FDC mode so you wouldn't hit fuel cut and that also was giving you a leaner top end. Probably around 12.5:1 ish. You said you didn't tune it by AFR but timing and I'm assuming knock. Now you have tuned it to w/e AFR you wanted to run and that is most probably the biggest reason for the drop in top end power. The MAF isn't a restriction that will hurt your power to the point where you could really tell on the but dyno. So you can't use that. If nothing else changed but the VPC going to MAFT then you can still get to the power you had before as mechanically nothing has changed.

But this does point to my previous post of the VPC just being outdated and also it's unstreetability. Although very opionated streetability or lack their of by me is pretty much going to mean unstreetable to 99% of the people here. I'll put up with a lot of stuff for power but if it just has no bottom end and the car is just a on/off switch then to me it's totally unstreetable.

I believe Carl Morris still using a VPC in his GVR4. You can always contact him on the DSM-ECU group and he can probably help you set up your VPC for the best street mannors.

 

[1LE]

You said you didn't tune it by AFR but timing and I'm assuming knock. Now you have tuned it to w/e AFR you wanted to run and that is most probably the biggest reason for the drop in top end power.

No knock count available, tuned purely by timing curve. No clue on the VPC setup AFR. Seems like 4g63s start to knock at 11.9AFR though, and I didn't have enough knock to visibly impact the timing. Hard to say for sure, would have been interesting to get it on the dyno like that, but it wasn't to be... My AFC is setup to be 11.8-11.9AFR (never leaner than 11.9).

Is it true for 4g63s (like for 3sgte's) that peak power is around 12.5AFR?

 

[GVR4592]

Is it true for 4g63s (like for 3sgte's) that peak power is around 12.5AFR?

It's pretty much the same for every engine.

http://www.max-boost.co.uk/max-boost/internet_articles/Air fuel metering.htm

 

[spinz4]

Hurling your tach needle to 8K w/ stock cams and recording higher airflow numbers w/ said stock cams at 8K are two totally different things.

Airflow climbs just fine.....Im sure it will be a lot better when I get the cams installed. None the less it makes power all the way up...

 

[dsm-onster]

Airflow climbs just fine.....Im sure it will be a lot better when I get the cams installed. None the less it makes power all the way up...

Well, you DO have a SMIM

 

[GVR4592]

Let's see a datalog of airflow climbing to 8k with stock cams.

 

[pboglio]

You aren't going to lose a lot of top end from adding a maf in front of the turbo. It's most likely a tuning issue.

I lose about 25 h.p. (via DSMLINK) or so when I pull my VPC off and add the 2g MAF back on. Also, the VPC leans the crap out of the motor which adds quite a bit of top end power if your not knocking. I've always run significantly faster with a VPC installed, although driveability can suck sometimes.