Supercharged VEC2 testing results...

Sean Roe · Jan 17, 2003

Hi Everyone,

Programming is almost complete on the VEC2.
The pre-production computer came in on Monday (was stuck in customs for 5 days). We built the wiring harness and started programming /dyno testing on Tuesday. Here’s the pre-production system:

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We ran the shop’s Supercharged GTS on our Clayton load dyno while linked up to the stock PCM and the VEC2. Air / fuel ratio’s were recorded on the Palm using the FJO wideband O2 system. Testing continued on our dyno, mixed with some street driving through Thursday evening.
Today, we went to the Dynojet facility we’ve used in the past and did more full throttle tuning. The dyno is about an hour and a half south of us, so it was also a good opportunity to put more time on the system.
In addition to meeting the objectives we had for the VEC2, it also produced a benefit. With direct control of the injectors, we were able to make a broader and higher power curve starting at a lower RPM. Below is a dyno graph showing the difference.

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You’ll notice that these graphs are SAE corrected for weather and altitude conditions at the time of the test. Today was cool, so the SAE corrction factor was .96. The actual measured power numbers were higher and you could definitely feel the torque on the bottom end when driving. Below is the raw data, showing measured and SAE corrected figures.

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The first production units are scheduled to ship to us late next week. We’ll keep you posted.

Sean

SUN RA KAT · Jan 17, 2003

This looks like the crowning touch for a great product.

Does this completely replace the VEC1 or can/should the VEC1 be used with the VEC2 for minor tweaking? Does the VEC2 have a LED display like the VEC1?

My Viper smiled at me when I told it the VEC2 is coming very, very soon.

CitySnake · Jan 17, 2003

As usual...
Nice to see all your hard work rewarded! Greatly looking forward to the V2! Not sure how I would have survived without the extra low end torque

KenricGTS · Jan 17, 2003

Is there anyway a guy could get more than just 5lbs of boost out of your system? Maybe a pulley change? I have had many supercharged cars(Vortech, NOVI 2000) and would at least get 8-10. I live a mile high I have noticed that when I went to sea level I would pick up 3lbs of boost. So it seems to me I would only see 2lbs of boost which would not be worth the trouble. I would buy your kit if I could at least get 8-10lbs of boost. Are you working on a kit with more boost smaller pulley more fuel? Thanks, Kenric

452rwhp
512rwt

jimandela · Jan 17, 2003

SUN RA KAT,
if your car smiled at you i better
get myself a SC and a VEC2

RedGTS · Jan 17, 2003

Kenric, you are correct that more boost is only a pulley change away, and Sean has several different sizes. I don't think he's had time to explore upping the boost due to having to address the pinging & related issues some people have had, which resulted in the development of the VEC2. I'm sure once the vEC2 is rolled out and working well he'll start experimenting with smaller pulleys.

varanus · Jan 18, 2003

believe me, boost is not just a pulley away. A lot of other factors will come into play.
It can be done, butit is not just swapping pullies

RedGTS · Jan 18, 2003

Swapping pulleys will spin the blower faster and up the boost. In fact, short of creating a constriction in the intake, engine, or exhaust tract that currently isn't there (not a good idea), how else would you up the boost?

If you mean some other things may have to be done to allow the safe use of the boost created by the smaller pulley, then I agree. I wasn't implying everyone could simply pop on a smaller pulley and be done with it--that's why I said Sean would be experimenting with it. If you mean something else will have to physically be done to create more boost, please elaborate.

1TONY1 · Jan 18, 2003

In kenric's case a pulley change will be all he needs at altitude. With the 7-8 psi pully he won't have anymore boost than the rest of us. If he comes off the hill, full throttle would be out of the question before more tuning comes about. Possibly a blow off adjusted to 5 psi would work at any altitude.

Sean Roe · Jan 18, 2003

Tony, Kevin and Ronnie are all correct.
Yes, we can simply make a smaller pulley and use a shorter belt to compensate for high altitude. We'd just need to see what boost the standard size gives you first, as a reference point. You'd want to have the larger pulley and belt anyway in case you were going to sea level for a while.
In regard to running more boost at sea level, it's not as simple as that (like Kevin said). The real issue is the volumetric efficiency of the engine compared to the blower. As it stands now, we begin to see boost creep at 5,200 rpm (stock engine with bolt-ons). At this point, the blower efficiency is staying steady and the engine efficiency is dropping. Adding more boost (CFM) will just make it creep higher and create extra heat (we tested this).
In order to increase and make use of the boost (CFM), we have to make the engine more efficient. Now that we have complete and proper control of fuel and timing, we can pursue plans to create a blower cam. Since you have to remove the heads, we'll probably do a little work on them too. The results should be good, but a fuel pump and injector upgrade will be needed to support it.
The other important issue we're about to get busy on again is emissions certification. We can now pass the cold start open loop warm up test.

Sean

This message has been edited by Sean Roe on 01-18-2003 at 03:22 PM

varanus · Jan 18, 2003

<BLOCKQUOTE>quote:<HR>Originally posted by RedGTS:
Swapping pulleys will spin the blower faster and up the boost. In fact, short of creating a constriction in the intake, engine, or exhaust tract that currently isn't there (not a good idea), how else would you up the boost?

If you mean some other things may have to be done to allow the safe use of the boost created by the smaller pulley, then I agree. I wasn't implying everyone could simply pop on a smaller pulley and be done with it--that's why I said Sean would be experimenting with it. If you mean something else will have to physically be done to create more boost, please elaborate.

<HR></BLOCKQUOTE>

I didn't want to say anything more elaborate, but since sean already mentioned it. Cam and headwork for exhaust breathing needs to be resolved. Othewise you're pumping in more air than you can exit.

RedGTS · Jan 18, 2003

Well I must admit I'm somewhat surprised by Sean's answer. I knew there were tuning and fuel supply issues that would need to be addressed to up the boost, but it's hard to believe a stock Viper engine can't physically handle more than 5 psi before things start backing up. Don't some of the other tuners' centrifugal kits run 8-10 psi (or more) through a stock motor? And if heating up the air is a major part of the problem, it would seem to me an intercooler or water injection (which I know Sean has used some) would be much more cost efficient than changing cams and working the heads.

Also, I know that knowledgeable tuners sometimes pump 20-30 psi through stock Mustang Cobra heads and produce ridiculous power (obviously the fuel supply and tuning issues have to be dealt with), and I have a hard time believing that a Viper flows air so poorly that it can't handle more than 5 psi. What's the deal here?

varanus · Jan 18, 2003

How would you put on an intercooler on the roe sc?

Surly 1 · Jan 18, 2003

Sean, great news! I was talking to mike last week as he was in your shop about you hooking me up soon. I have a 2000 RT/10 with only exhaust mods done. My concerns are the effects on the cast rods and pistons in my stock motor after using boost. Am I worrying needlessly? Has anyone else had problems with 2000 and up supercharger mods?

Looking forward to meeting you soon!

1TONY1 · Jan 18, 2003

<BLOCKQUOTE>quote:<HR>Originally posted by varanus:
How would you put on an intercooler on the roe sc?

<HR></BLOCKQUOTE>

You would have to put it between the intake and blower. Figure on 2 to 3 inches......anybody want to cut a hole $$$ in their hood ?
Hmmmm, a cowl hood on a Viper.
Water injection is not as good as with a turbo or centrifical s/c either. Certainly not as easy due to possible distribution problems.

RedGTS · Jan 18, 2003

<BLOCKQUOTE>quote:<HR>How would you put on an intercooler on the roe sc?<HR></BLOCKQUOTE>

Sandwiched in between the blower and the intake (really it's basically integrated into the intake). Whipple has one they use with their screw blowers, and the '03 Cobra uses one with the Eaton blower as well. Sean mentioned one time during development that there was room for one, but I don't think he's explored the issue.

BTW, Kenne Bell replaced the Eaton unit on the '03 Cobra with one of their Blowzilla units (2.2 liter Autorotor) and got 617 rwhp (251 rwhp greater than stock) after cramming 20-22 psi through the stock MAF meter and throttle bodies into a stock engine and out through the stock cats. This is very similar to the Autorotor unit Sean is using, which as I recall is a 2.3 or 2.4 liter Autorotor. And yet another reason I do not understand why our Vipers are going to need internal engine mods to handle more than 5 psi of boost from this blower.

Sean Roe · Jan 19, 2003

Ronnie,
In my above reply I put CFM after the word boost. This was to remind people that it's air flow issue, not boost pressure. We can run 8 lbs and more of boost, but you'll only see a power increase up until the engine can't flow enough air (causing boost creep in the manifold). If you want to run 8 lbs on a stock engine with forged pistons, you can. But, I'd recommend shifting by 5,500 rpm. The guys with the centrifugal blowers are probably experiencing the same thing, but it's not as visible (the centrifugal moves more air as the RPM increase, so you expect the boost to go up, where the positive displacement is always the same, with any volumetric efficiency variation showing up as a change in the manifold pressure).

In regard to the cast pistons, 5 lbs with some boost creep at the top end has been safe. I wouldn't suggest running more than that. It's not the strength of the piston that's a problem. It's the lack of piston material above the top ring land. That's direct from Mahle, the piston manufacturer.

The VEC2 is meant to replace the VEC1 and MSD boxes on the SC'd cars. The VEC1 can increase timing advance, where the VEC2 cannot.

Sean

RedGTS · Jan 19, 2003

Sean, thanks for the reply. And of course I understand airflow or massflow as it's sometimes called is the overall issue rather than just boost, but I still don't understand why the Autorotor KB put on the Cobra I mentioned seems to produce more and more power on a stock engine as it is turned faster (which creates more boost because the engine's capability to flow air remains the same), yet a similar Autorotor on a Viper runs into power sapping "boost creep" somewhere between 5 and 8 psi. UNLESS the answer relates to the relative size of the blowers (more specifically the amount of air they move per revolution) versus the size of the engine (2.2L blower on a 4.6 liter engine versus a 2.3 or 2.4 liter blower on an 8.0 liter engine), and the difference in efficiency of a similar sized blower on a much larger engine. But you specifically said that the blower efficiency remained the same, and it was the ENGINE efficiency that was dropping and causing the boost creep and associated heat. And opening up the engine will require even higher blower speeds to get back to same boost level (albeit at a higher power level). I guess I've been under the impression that, so long as you remained in the blower's reasonable efficiency range, you could spin it faster and faster and produce more power so long as you 1) dealt with the need for extra fuel; and 2) dealt with the rise in heat via some combination of octane or an intercooler and appropriate tuning. I've never heard of a situation before where the blower was supposedly capable of supplying more air efficiently but the engine had to be opened up in order to use it. But then again I'm far from an expert on these issues.

I know there are a lot of variables involved, and I know you've had no time lately to devote to this issue. I'm just trying to understand the potential of this blower and what will be necessary to produce another 100 or 150 rwhp down the road, if that's even possible/advisable. Thanks!

Snakester · Jan 19, 2003

Sean,

I know that one of the main reasons for the VEC2 development was to work with your SC, but I was wondering if you have tested the VEC2 with regular Vipers and N20 setups, and what the price difference will be relative to the VEC1.

I had been looking at the VEC1 as a point of tuning, and possibly working with a mild N20 shot.
And the VEC2 sounds like it could be a better solution for that application.

-Dean.

kverges · Jan 19, 2003

I noticed the calibration data file appears to have been marked for '96-99 GTS; what will be the story for later cars? Different calibration for the cast pistons and what power do you anticipate?

Thanks,

varanus · Jan 20, 2003

<BLOCKQUOTE>quote:<HR>Originally posted by RedGTS:
Sandwiched in between the blower and the intake (really it's basically integrated into the intake). Whipple has one they use with their screw blowers, and the '03 Cobra uses one with the Eaton blower as well. Sean mentioned one time during development that there was room for one, but I don't think he's explored the issue.

BTW, Kenne Bell replaced the Eaton unit on the '03 Cobra with one of their Blowzilla units (2.2 liter Autorotor) and got 617 rwhp (251 rwhp greater than stock) after cramming 20-22 psi through the stock MAF meter and throttle bodies into a stock engine and out through the stock cats. This is very similar to the Autorotor unit Sean is using, which as I recall is a 2.3 or 2.4 liter Autorotor. And yet another reason I do not understand why our Vipers are going to need internal engine mods to handle more than 5 psi of boost from this blower.

<HR></BLOCKQUOTE>

Ronnie . .is there enough room . I thought of that spot but didn't think there would be enough clearence w/o cutting into the hood.

I read the same article as you did. Sean explained the volumetric efficiency and boost creep and it all makes sense, but it seems all the other motors are able to handle it. That is they still have room to go before their ability to pump out air is exceeded by what goes in.
The 03 cobra started with 8 psi and 375 rwhp with the stock eaton. They went as high as 456 rwhp with pulley changes even with a plugged up exhaust. Then with the kb at 18 psi they got up to 617 with a larger blower so it appears that the motor can still breath.

With a rise in boost from 8 psi to 18 psi they did not seem to encounter creep. That is over double the boost. Yet on the viper is appears as soon as as we go up 1 lb we are exceeding the capability of the v-10.

So my question is are we missing something or is the viper motor just one of the most ineffecient or maxed out designs for flow. I can see where the viper may not be able to handle as much extra breathing of more boost the mustang, but we can't do anything at all. How does levin and Heffner do it. Are they having to port out the heads and do cams to handle the boost increase.

Anyone got any ideas? Just seems wierd that the viper is stuck at such a low level.

1TONY1 · Jan 20, 2003

IMHO.....All the breathing issues aside, We will be able to do 7 - 8 psi with forged pistons and the correct tuneup/fuel upgrades. The problem after that is the air temp and no intercooler. This kit was not designed to make 900 hp and 12 lbs. of boost. Now with the correct custom water injection the charge temp will come down but its going to take a custom system to do it. If you want more call Heffner or add n02.

Sean Roe · Jan 20, 2003

<BLOCKQUOTE>quote:<HR>Originally posted by kverges:
I noticed the calibration data file appears to have been marked for '96-99 GTS; what will be the story for later cars? Different calibration for the cast pistons and what power do you anticipate?

Thanks,
<HR></BLOCKQUOTE>

Hi Keith,

We've been testing with different model years of PCM and are recording the results to see if a calibration change is necessary. So far, the curves through a 2001 (the newest one I have) are very close to the same.
On most of the 2000 and newer cars with the kit, the gain has been the same (28%).

Sean

Miles B · Jan 20, 2003

Doesn't the Mustang have a 4 valve per cylinder engine? Wouldn't that help volumetric efficiency in the upper engine speed range?

onerareviper · Jan 20, 2003

I know, I know.... Too much is never enough. But come on, Sean's kit is over 700HP (at 5 psi) with full exhaust and bigger throttle bodies. On the street with Michelin Pilots, I can't imagine any more HP being useable. I'm more concerned with reli-ability, drive-ability, tune-ability, ease of installation, and cost. Hopefully the VEC2 will solve 3 outta 5, and the cost/ease of installation has never been a major issue.

my .02

Jerome Sparich · Jan 20, 2003

Bingo! Finally someone said the magic words.

Yes it is a 4 valve per cyl. engine.

1TONY1 · Jan 20, 2003

<BLOCKQUOTE>quote:<HR>Originally posted by varanus:
Hey Tony. I have the water injection from Kennedy's dynotune which they use on kb sc mustangs. I haven't installed it yet as I am waiting for the VEC 2. Have you heard of this? I am thinking of spraying before the tb's I talked with Sean and he said it would be fine. He said he had experimented with cruder methods of water injection and got good results. What are you thoughts for water injection
It is boost sensitive so I am thinking it needs to be set at maybe 2 or 3 lbs at about 1900 rpm or so. What do you think?

<HR></BLOCKQUOTE>

I wonder if the atomization is still going to be there after it travels all the way thru the intake tubes then thru the blower. In most cars such as turbos and centrifical s/c it goes in after the air maker....meaning lots more turbulence/airflow etc. Is the flow of air in the intake tubes going to hold the water in the air???I don't know. Also most run alcohol/water or methanol even straight methanol is becoming popular......there is a corrosion problem unless its straight water. I'm not sure if I would want that in my blower. I think a 2 or 4 nozzle system in each end of the intake would be the best. The Buick guys are the experts and this is what I have come up with from them. ta

RedGTS · Jan 20, 2003

I'm obviously not knocking Sean's kit--I bought one, and I'm looking forward to installing it in the near future. And Sean has never marketed the kit as anything other than one that will produce a solid hp gain at a very reasonable price, and that can be done on a DIY basis. But I know I'm not the only one interested in the limits of the setup and its ability to be upgraded down the road for more power if one desires. I'm curious about this not only because I think I may well want more power, but because I want to understand the technical reasons involved in the answer. Call it an academic exercise, to a certain extent, the outcome of which will not reflect poorly on what Sean has done no matter what the answer. Now as far as not needing or being able to use more than 700 crank hp on the street, well, let's just say I know there are several people who post here that will disagree with that thesis.

As for Jerome, yes, the Cobra has 4 valves per cylinder, but I don't think there's anything magic about that. I'm sure it allows the engine to make more power at a similar boost/flow level than an otherwise identical 2v motor would (particularly at high rpm), but it hardly explains why a Viper engine needs ported heads or a cam to handle more than 5 or 6 pounds of boost out of this blower. Perhaps a more apt comparison is found in one of the articles on Kenne Bell's site about their Autorotor upgrade for the Lightning, which as you may know is a 5.4 liter 2v motor. As I recall they pulleyed down (or in the case of the crank pulley, pulleyed up) the Autorotor on the Lightning to the point it produced over 20 psi and over 500 rwhp. Now they were using a very efficient intercooler, race gas, and some careful tuning, but again this was without touching the inside of the engine or even the stock exhaust--no headers, no high-flow cats (they did change throttle bodies and air filter, as I recall).

So I remain curious as to why the engine itself would need opening up as opposed to simply upping the boost and dealing with the potential detonation issues via some combination of an intercooler (or water injection), octane, and tuning.

varanus · Jan 21, 2003

Hey Tony. I have the water injection from Kennedy's dynotune which they use on kb sc mustangs. I haven't installed it yet as I am waiting for the VEC 2. Have you heard of this? I am thinking of spraying before the tb's I talked with Sean and he said it would be fine. He said he had experimented with cruder methods of water injection and got good results. What are you thoughts for water injection
It is boost sensitive so I am thinking it needs to be set at maybe 2 or 3 lbs at about 1900 rpm or so. What do you think?

GTS-R 001 · Jan 21, 2003

Ronnie,

I think you are correct. Even though the blower might maintain efficiency and the viper engine's volumetric efficiciency declines as boost increases, with the proper amount of adequate octane fuel, power should increase. It does so in all other engines so it will in a viper engine as well ( no magic tuner pixie dust required ).

steve

Supercharged VEC2 testing results...

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