Dyno for a Harrop in an Ariel
I bet that was you that drove past my house this last summer. I was like what the heck is that sound then I saw the Atom cruz past. I live just off of Jovita, on the road that everyone takes the shortcut to Military Rd. on. If that was you, do you know a guy over in your area that drives a blue 66 or 67 nova, I use to see it rumble by the house all the time and one day followed him out to the Lk Tapps area
Junior Member
Joined: 10-28-08
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From: Milton WA
I used to drive that road to the office. I moved my office in 2007 and don't drive it very much anymore. Could have been me, maybe not. I think that I know the Nova you are speaking of, kind of a bad ass pro street? I have seen it that is all, ...well I have heard that great rumble also.
(the Cobalt SS/TC is on order)
Rent me! per hour
Joined: 03-22-07
Posts: 24,161
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From: Still fixing others mistakes.
Just got the dyno done on Tuesday! Basically, +/-315 whp corrected (c) / 297 whp uncorrected (uc) and greater than 250(c) LB/ft of torque from 3300-6500 rpm with a peak of 272(c). The corrected / uncorrected calculation was from the owner of the dyno and appears to be about a %6 factor. We had another Atom there at the same time and the curves were exactly proportional to each other. In other words the same growth curve with no hiccups. The other Atom is a Ecotec with a 2.8 pulley, meth injection, 60 lb. injectors and a Fortress Exhaust. Since the other Atom is an Eaton taken to about the same level, it equates to a +/-50 whp bump. I don't remember his torque numbers, but, the curves were amazingly proportional. So far my builder's heat restraint measures were working with no excessive heat build ups during the pulls. What I mean by that is that it didn't act like a Heaton and acted more like a normal car.
Take the horsepower and torque numbers in proper context. I had the car tuned for what I can get out of the pumps here in Washington. We can only get oxygenated fuel that has %10 ethanol in it and then the best octane rating is 92. According to the tuner this equates to a horsepower drop in Cobalt's of 35-45 whp from what can be achieved elsewhere. That means that I would have hit my personal goal of 350 whp if I didn't live here. Now I have to figure out how to best explain to the wife that we are moving because of someone pouring alcohol in my gas ...
(Some of the posts following this explain that our fuel does not have ethanol in it)
The boost was a linear build with both the 85mm and 80mm pulleys till just about redline. Both pulleys had a boost spike just prior to redline of 3 lb. for the 85 and 2 lb. for the 80. The 85 yielded 17 lb. with a quick spike to 20. This was never tuned out as we switched to the 80 which built smoothly to 20 lb. and spiked 2 lb. just at the end.
(I have since reviewed the plot and the tuner cleaned out the spikes, none are apparent now. 22 lb steady towards the end)
The larger throttle body is causing drive ability issues at low rpm. Below 3000 it feels like you can push the throttle and nothing is happening. By pushing the throttle, I mean slightly as in trying to slowly accelerate, if you slam the throttle the rear tires mysteriously loose traction and the steering gets vague. When I feel this hesitation, I know that it is about to buck, so I will short shift it. This is a quick fix and does work. The tuner is creating a throttle map that will open the throttle butterfly slower at lower rpm's and get rid of this.
My engine and the other Atom's engine both exhibited a strong steady hp curve growth to 6000 rpm and then they just go flat to redline. The engines seem to be running out of air. Ported heads, cams or something else in the future ... The tuner wants to run one of the two cars without the Supertrapps on the Fortress system to see if that is that problem. He has tuned turbo LSJ's with the same boost and they did not exhibit the same issue.
It is a rocket! Not that I will not get used to it, so, I will need to start planning next years improvements ...
Take the horsepower and torque numbers in proper context. I had the car tuned for what I can get out of the pumps here in Washington. We can only get oxygenated fuel that has %10 ethanol in it and then the best octane rating is 92. According to the tuner this equates to a horsepower drop in Cobalt's of 35-45 whp from what can be achieved elsewhere. That means that I would have hit my personal goal of 350 whp if I didn't live here. Now I have to figure out how to best explain to the wife that we are moving because of someone pouring alcohol in my gas ...
(Some of the posts following this explain that our fuel does not have ethanol in it)
The boost was a linear build with both the 85mm and 80mm pulleys till just about redline. Both pulleys had a boost spike just prior to redline of 3 lb. for the 85 and 2 lb. for the 80. The 85 yielded 17 lb. with a quick spike to 20. This was never tuned out as we switched to the 80 which built smoothly to 20 lb. and spiked 2 lb. just at the end.
(I have since reviewed the plot and the tuner cleaned out the spikes, none are apparent now. 22 lb steady towards the end)
The larger throttle body is causing drive ability issues at low rpm. Below 3000 it feels like you can push the throttle and nothing is happening. By pushing the throttle, I mean slightly as in trying to slowly accelerate, if you slam the throttle the rear tires mysteriously loose traction and the steering gets vague. When I feel this hesitation, I know that it is about to buck, so I will short shift it. This is a quick fix and does work. The tuner is creating a throttle map that will open the throttle butterfly slower at lower rpm's and get rid of this.
My engine and the other Atom's engine both exhibited a strong steady hp curve growth to 6000 rpm and then they just go flat to redline. The engines seem to be running out of air. Ported heads, cams or something else in the future ... The tuner wants to run one of the two cars without the Supertrapps on the Fortress system to see if that is that problem. He has tuned turbo LSJ's with the same boost and they did not exhibit the same issue.
It is a rocket! Not that I will not get used to it, so, I will need to start planning next years improvements ...
Last edited by ArielAtom; Apr 19, 2009 at 01:01 PM. Reason: Added or clarified as in parenthesis
Senior Member
Joined: 09-21-06
Posts: 2,270
Likes: 1
From: Midwest
Take the horsepower and torque numbers in proper context. I had the car tuned for what I can get out of the pumps here in Washington. We can only get oxygenated fuel that has %10 ethanol in it and then the best octane rating is 92. According to the tuner this equates to a horsepower drop in Cobalt's of 35-45 whp from what can be achieved elsewhere.
I've seen the best power from my own motor by blending 93 Octane 100% alcohol with E85, filling the tank with 11 gallons gas and two gallons E85. I am confident, that if I had the time and equipment to get it finished, I'd see even better power out of 100% E85.
Fuel Economy on, the other hand, probably would suffer a little.
Your tuner is wrong. First off, there is a difference between reforumated/oxygenated fuel and fuel that just has 10% ethanol added to it. Second, the ecotec likes timing, and alcohol allows for better timing. Now the fact that you don't have the best fuel is certainly holding you back a little bit, but I very much doubt it is anywhere near 45whp.
I've seen the best power from my own motor by blending 93 Octane 100% alcohol with E85, filling the tank with 11 gallons gas and two gallons E85. I am confident, that if I had the time and equipment to get it finished, I'd see even better power out of 100% E85.
Fuel Economy on, the other hand, probably would suffer a little.
I've seen the best power from my own motor by blending 93 Octane 100% alcohol with E85, filling the tank with 11 gallons gas and two gallons E85. I am confident, that if I had the time and equipment to get it finished, I'd see even better power out of 100% E85.
Fuel Economy on, the other hand, probably would suffer a little.
We are "officially" oxygenated fuel, is that not the same as 10% ethanol added?
Senior Member
Joined: 09-21-06
Posts: 2,270
Likes: 1
From: Midwest
One of the biggest reasons people are ignorantly against E85 is because they confused the reformulated/oxygenated fuel with the 10% ethanol fuel. This is because, ethanol does have a higher oxygen content than normal gasoline, so people assume the two are the same as they share a few qualities.
Nope, they are not the same. Oxygenated/Reformulated gasoline is worse in every way than both normal gasoline and ethanol. It costs money and creates polution to perform the process, and because you burn more of it, it is worse for the environment. Study after study has shown this. I would believe it could cause the drop your quoting. There are none of the positives of ethanol added fuel in reformulated to allow for better timing, and it has still has less energy potential.
One of the biggest reasons people are ignorantly against E85 is because they confused the reformulated/oxygenated fuel with the 10% ethanol fuel. This is because, ethanol does have a higher oxygen content than normal gasoline, so people assume the two are the same as they share a few qualities.
One of the biggest reasons people are ignorantly against E85 is because they confused the reformulated/oxygenated fuel with the 10% ethanol fuel. This is because, ethanol does have a higher oxygen content than normal gasoline, so people assume the two are the same as they share a few qualities.
What is reformulated/oxygenated fuel then?
Yes, it was. Good bunch of guys. It now looks like I will have to go back and do a run without the Supertrapps on. I think that I saw that the locals were putting together a day here in the near future. I am going to try to get in on that.
I will be curious what you make also. You list 20 psi, so, you are running the 85 mm pulley? I made about 10-15 less whp with it. You don't list meth injection either. You will be running better fuel, so, I will be very interested.
