Big Bad Monster Engine from Imagine Auto
09-04-2003, 09:11 PM
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Three Wheelin'
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Big Bad Monster Engine from Imagine Auto
Hey Guys - I thought I would post the dyno results from my 3.4 twin plug engine as built by Stephen at Imagine Auto. I will have jpegs of the dyno sheets to post later today. The engine was completed last September and I wanted a good long break in before throwing her on the Dyno. I knew the power was substantial, but as I have an adjustable boost controller I wanted to see how the AF ration held up with different boost levels. To this point I have left the boost controller set at .8 bar.
So here are the numbers (all power numbers at the wheels):
85 Degree ambient temp
Boost HP Torque Max A/F Ratio
.8 Bar: 395 412 13 (from 5800 on up)
.85 Bar 398 416 13.1 (from 6,000 on up)
.9 Bar 403 426 13 (5,400 on up) - note that on this run it was mostly in the .8 bar range; .9 was only hit briefly)
So using the best run, we have approximately 475 HP and 500 foot lbs. torque. We are over 375 ft lbs at the wheels starting at 3,000 RPMs and hold that all the way past 6,000 RPMs.
We played with the fuel enrichment settings a bit and all they did was bog down the car from say 2800 RPMS to 4500 RPMs (the AF ratio actually drops to 10 in this range). Given this, I want to see if I can increase boost in that range to dial it in a bit more. There is really nothing to do with the top end numbers as the turbo and fuel system are both maxed out - but I may be able to dial in more midrange as we are leaving some on the table. For example I may be able to tune in 400 torque at the wheels starting at 3,000 RPMs - which is just awesome.
I will post a dyno sheet later.
So here are the numbers (all power numbers at the wheels):
85 Degree ambient temp
Boost HP Torque Max A/F Ratio
.8 Bar: 395 412 13 (from 5800 on up)
.85 Bar 398 416 13.1 (from 6,000 on up)
.9 Bar 403 426 13 (5,400 on up) - note that on this run it was mostly in the .8 bar range; .9 was only hit briefly)
So using the best run, we have approximately 475 HP and 500 foot lbs. torque. We are over 375 ft lbs at the wheels starting at 3,000 RPMs and hold that all the way past 6,000 RPMs.
We played with the fuel enrichment settings a bit and all they did was bog down the car from say 2800 RPMS to 4500 RPMs (the AF ratio actually drops to 10 in this range). Given this, I want to see if I can increase boost in that range to dial it in a bit more. There is really nothing to do with the top end numbers as the turbo and fuel system are both maxed out - but I may be able to dial in more midrange as we are leaving some on the table. For example I may be able to tune in 400 torque at the wheels starting at 3,000 RPMs - which is just awesome.
I will post a dyno sheet later.
09-04-2003, 11:01 PM
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Three Wheelin'
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O.K. - here is the dyno sheet:
You can see the awesome torque from 3000 RPMs on. You can also see where the fuel enrichment comes on and causes a bit of a problem as it is very rich. As I have a electronic boost controller that allows me to set boost level every 500 RPMs, I am going to set the boost higher from 3000 to 4500 RPMs to take advantage of the extra fuel and hopefully smoth out and fatten up the midrange power a bit.
As a point of reference, here is my old dyno sheet with just bolt on mods: K27 7200, Kokeln IC, GHL headers, SC Cams, 1 bar spring (tested at 1.05 bar), Mille Miglia exhaust. Looking at 3000 RPMs, the torque on the new sheet is 375 vs. 225 on the old sheet.
You can see the awesome torque from 3000 RPMs on. You can also see where the fuel enrichment comes on and causes a bit of a problem as it is very rich. As I have a electronic boost controller that allows me to set boost level every 500 RPMs, I am going to set the boost higher from 3000 to 4500 RPMs to take advantage of the extra fuel and hopefully smoth out and fatten up the midrange power a bit.
As a point of reference, here is my old dyno sheet with just bolt on mods: K27 7200, Kokeln IC, GHL headers, SC Cams, 1 bar spring (tested at 1.05 bar), Mille Miglia exhaust. Looking at 3000 RPMs, the torque on the new sheet is 375 vs. 225 on the old sheet.
09-05-2003, 12:13 AM
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Bill, that is a very nice tq and hp curve. Are you still using the 7200 turbo? I think you are since you get full boost at 3k rpms, how long do you hold boost for before it drops off any? Still one of the best dyno charts I have seen.
Just a word of caution that your A/F will go up around a half point when the weather cools down so try for another .5-1 point of fuel at the top end using your enrichment device. Though the down side is like you said in that mid range you lose power with such a rich A/F. BUT, very cool that you can increase the boost by rpms to help level that fuel curve out (what EBC do you have?). On the other hand if you do that then more air is going to flow through the venturi and force the plate down more just to give you the same A/F possibly. The reason it leans out later is because the plate has dropped enough where the air is now mostly bypassing it with the same control pressure since your enrichment is sensed by boost and not rpms. I was thinking of an rpms switch to control the enrichment so you run your warm control pressure only until you need your enrichment pressure. Let us know if controlling the boost will flatten out the fuel curve or not.
Way to go and Stephen too,
Brent
Just a word of caution that your A/F will go up around a half point when the weather cools down so try for another .5-1 point of fuel at the top end using your enrichment device. Though the down side is like you said in that mid range you lose power with such a rich A/F. BUT, very cool that you can increase the boost by rpms to help level that fuel curve out (what EBC do you have?). On the other hand if you do that then more air is going to flow through the venturi and force the plate down more just to give you the same A/F possibly. The reason it leans out later is because the plate has dropped enough where the air is now mostly bypassing it with the same control pressure since your enrichment is sensed by boost and not rpms. I was thinking of an rpms switch to control the enrichment so you run your warm control pressure only until you need your enrichment pressure. Let us know if controlling the boost will flatten out the fuel curve or not.
Way to go and Stephen too,
Brent
09-05-2003, 12:40 AM
#4
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One of the things that most people don't know is that you can adjust the on point of the Hobbs switch for the enrichment. Might be worth moving the enrichment range up a hair to help control a little more toward the top, rather than the mid.
Bill is running an Apexi AVCR..Pain to install, great features
Bill is running an Apexi AVCR..Pain to install, great features
09-05-2003, 01:35 AM
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Well whatever you guys can recommend to get the upper AF ratio down - I'm all ears.
Brent - Stephen tells me you have a modification to the WUR that can help with this? I am running a K27-7200 so I am close to the max at the top. Even when I increase the boost at the top end the actual boost drops off to .8 or so by 6,000 RPM. On the low end I see boost starting below 1500 RPM - which explains 220 ft lbs of torque at 2000 RPM. Stephen deserves all the credit for this - all I did was give my credit card number to his wonderful wife.
Stephen - what is the Hobbs switch and how can I adjust it?
The car is awesome now. If I can I would like to get 400 torque from 3000 RPMs up.
P.S. - with that fat torque curve, the stock 4 speed works really well
Brent - Stephen tells me you have a modification to the WUR that can help with this? I am running a K27-7200 so I am close to the max at the top. Even when I increase the boost at the top end the actual boost drops off to .8 or so by 6,000 RPM. On the low end I see boost starting below 1500 RPM - which explains 220 ft lbs of torque at 2000 RPM. Stephen deserves all the credit for this - all I did was give my credit card number to his wonderful wife.
Stephen - what is the Hobbs switch and how can I adjust it?
The car is awesome now. If I can I would like to get 400 torque from 3000 RPMs up.
P.S. - with that fat torque curve, the stock 4 speed works really well
09-05-2003, 02:26 AM
#6
Rennlist Lifetime Member
The hobbs switch is the black sensor that is hooked up to the intercooler. There are two lines that come off of it and go to the Andial unit. In the end of the unit there is a black rubber plug. Under that is a hex head, or at least use to be hex. This can be adjusted to come in at a higher level. You can either adjust it on the road and see when the system comes in via the light or remove it and apply air until it comes up tot he level you want. You can put a meter across the terminals and can tell when the switch activates.
09-05-2003, 02:56 AM
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Bill,
I might be able to help but I need to know what WUR and enrichment device you currently have. Sounds like you have the Andial and therefore I couldn't do much better but you should run just a little richer to keep safe up top. Mine is just a different variation of what Lee does but on boost instead of losing vacuum. I had my fuel head rebuilt and got 17% more fuel across the range and run just 3.35-3.4bar of enrichment at 10+ pounds using a boost controller to delay it. I even ran up to 16psi with no enrichment to see what margin I had and still didn't run out of fuel at 452rwhp 12.6:1 A/F. You should look into getting your fuel head upgraded but then you will need to modify your WUR (I can do that). With that done and the Rice fueler I baried the 10:1 line and must have been like 9:1 before disconnecting the vacuum/boost line from the WUR and re dyno.
As for your boost drop off, your out flowing the turbo which many people experience with high hp CIS cars. Be careful come Fall, I was all over the road with that amount of tq early.
Enjoy
I might be able to help but I need to know what WUR and enrichment device you currently have. Sounds like you have the Andial and therefore I couldn't do much better but you should run just a little richer to keep safe up top. Mine is just a different variation of what Lee does but on boost instead of losing vacuum. I had my fuel head rebuilt and got 17% more fuel across the range and run just 3.35-3.4bar of enrichment at 10+ pounds using a boost controller to delay it. I even ran up to 16psi with no enrichment to see what margin I had and still didn't run out of fuel at 452rwhp 12.6:1 A/F. You should look into getting your fuel head upgraded but then you will need to modify your WUR (I can do that). With that done and the Rice fueler I baried the 10:1 line and must have been like 9:1 before disconnecting the vacuum/boost line from the WUR and re dyno.
As for your boost drop off, your out flowing the turbo which many people experience with high hp CIS cars. Be careful come Fall, I was all over the road with that amount of tq early.
Enjoy
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09-05-2003, 12:53 PM
#8
Bill,
I think your very safe running anywhere betwen 0.9 to 1 bar with your setup/fueling. What causes detonation is the extra heat built up with wrong tuning, a/f ratio which you and I dont. I run safely with a 0.9 spring which sees just under 1 bar on higher gears and speed with my Andial unit dialed into at 3rd nothch and 3% CO.
I think your very safe running anywhere betwen 0.9 to 1 bar with your setup/fueling. What causes detonation is the extra heat built up with wrong tuning, a/f ratio which you and I dont. I run safely with a 0.9 spring which sees just under 1 bar on higher gears and speed with my Andial unit dialed into at 3rd nothch and 3% CO.
09-05-2003, 01:12 PM
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Stephen and Brent - we can take this offline if you like, but I am still interested in getting better fule flow at the top. Although running above 5500 RPMs at full boost is a very rare occurence for me, I would like the extra protection.
Stephen - you are talking over my head a bit. Are you saying I can adjust a screw and get better top end fuel flow? If so, perhaps I should schedule some more dyno time and try this out.
Stephen - you are talking over my head a bit. Are you saying I can adjust a screw and get better top end fuel flow? If so, perhaps I should schedule some more dyno time and try this out.
09-06-2003, 12:22 AM
#10
Rennlist Lifetime Member
You can adjust the **** inside, but as you indicated the mid range would just get worse. So you want to move the boost activation point up-wards on the boost scale. So instead of coming on around .4 bar you could push it to .6 or .8. This will supplement the top only.
