I recall a while back a discussion regarding whether the Bullitt's hp was brought down due to a different camshaft profile. Speculation was that this would bring hp levels down more towards the GT's rather than the Cobra's. I was wondering if anyone has heard anything more on this?
Camshaft Profile Question
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I have been trying to get thru "back doors" to find out anything on the Bullitt engine specs. without much luck. The people at Roush weren't talking. Tried to get cam specs on the basic 01 GT,hearing they are the same,from MM&FF Tech Ed.,but he doesn't know either. Why so much secrecy on an engine I will never understand.....Give me back the old days!
I don't have any specs on the '01 cams, but the 99-00 GT cams have 12.86 mm (0.51 in.) valve lift on the intake side and 13.56 mm (0.53 in.) on the exhaust side. I suspect that the '01 GT cams are identical, although I have no firsthand knowledge of this.
Thanks for the info. I really wouldn't be surprised if our cams are not the same as the '01 GT's. There were posts sometime about early July/ late June that the Bullitt motor was making very good horsepower when it was presented as a finished concept to Ford, but when the final production version came back -- less power was actually seen than predicted. This led to the revised 265 hp rating as opposed to the original higher numbers. I really believe Ford may have pulled a cam switch on us to keep these motors away from the Cobra's power level. I'm probably wrong and missing this by a mile, but it just seems that way. Plus, why is there so little information out there to be found on the Bullitt's actual specs? Granted, it's a "new" engine, but I'm telling you there's a conspiracy going on here. ( As an example, the '88 GTs made a solid 225 horsepower [I had one and loved it], but then after a few model years the horsepower rating was revised by Ford to 215, even though it was still the same engine. The basic difference? Switched cams.) Maybe Crane, Comp Cams or one of the other larger camshaft producers will pull apart a Bullitt and see what we've got and what we could use.
Crane, SHM, and Erson all have cams available for the 4.6 SOHC. The Crane units seem to be the most popular, however they are regrinds, not "new" cams.
I would guess that the Bullitt cams are the same as the 99-01 cams, but like I said, I have no proof of this.
I would guess that the Bullitt cams are the same as the 99-01 cams, but like I said, I have no proof of this.
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It is entirely possible that they used milder camming for these engines. That coupled with a less aggressive computer, prototype to mass produced intake, and other things could have mellowed the output.
As mentioned above earlier SEFI 5.0's had more power than later ones. It was not uncommon for stock 5.0's to have 235-242 flywheel hp. Then by 93, the power rating fell to 215. A few things come to mind here. They made cam modifications through those years. One reason was because of aggressive ramp rates that tended to make a little more rocker noise. The computers by 1993 were not as aggressive as the early A9L and not even close to the A9P. And believe it or not, we have found no less than 5 different lower intake manifolds on 87-93's. While they all look the same from the top, the lowers varied greatly. And as chance would have it, the Cobra was ready to make it's return by 1993. They had to create enough difference to make it worth while. A 20 hp jump for the Cobra would seem much better than 10 (and in truth maybe less). It seems this may have happened again.
As mentioned above earlier SEFI 5.0's had more power than later ones. It was not uncommon for stock 5.0's to have 235-242 flywheel hp. Then by 93, the power rating fell to 215. A few things come to mind here. They made cam modifications through those years. One reason was because of aggressive ramp rates that tended to make a little more rocker noise. The computers by 1993 were not as aggressive as the early A9L and not even close to the A9P. And believe it or not, we have found no less than 5 different lower intake manifolds on 87-93's. While they all look the same from the top, the lowers varied greatly. And as chance would have it, the Cobra was ready to make it's return by 1993. They had to create enough difference to make it worth while. A 20 hp jump for the Cobra would seem much better than 10 (and in truth maybe less). It seems this may have happened again.
01GTB, I appreciate the information you posted. I wasn't aware of the different lower intake manifolds thoughout those years you mentioned. What you've posted really makes me wonder about the Bullitt v. Premium GT v. Cobra power hierarchy. I'd really like to arrive at a satisfactory answer of what happened to our "lost horsepower" so that those of us who would be inclined to correct Ford's tinkering could do so to get back to the original horsepower numbers thrown around originally. I think it would be a hoot if we could make just a few mods to our motors and have honest 300-320 hp cars.
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The Bullitt upper intake builds the torque the GT intake doesn't. But it probably costs some horsepower in the process. Long runner intakes do that, it's their nature. In a naturally aspirated street car, it's ok to sacrifice some horses for some ft-lbs. Prototypes may have had some altered runner lengths, who knows. The fact is, there is a platform to work with and when the bugs are worked out, the flywheel numbers of 300hp are possible. Mark my word, by the end of winter, someone will have run deep in to the 12's with no power adder. I don't know what Black Sunshine's combo is so I can't say it's been done yet. His numbers seem to say power adder, but who knows.
no power adders........yet. Just traction and planting all the power to the ground with a little help of a few minor mods and lots of track practice on the launch. 12's arent hard with the right combo and a good driver. IMO...if you want to get into the 12's for a little money, go with a drag setup and change out the entire suspension. my next stop...11's
I only have 90 miles on my Bullitt so I can't really comment on the power levels. On my '00 GT it had a definite "hit" at about 4000 rpm. It seemed to really come on the cam at 4k and there was a noticable power increase. When I get a few more miles on the Bullitt I'll see if it feels the same way.
Another consideration is that the '99-00 GT engines were built at Ford's Windsor plant. The '01-02 engines are built at the Romeo engine plant. I understand there were several changes made to the engines themselves along with the change of manufacturing locations. It's also worth noting that there was a change in the design of the front pulleys from 99 to 00, that's why a supercharger kit for a 99 won't fit a 00. So technically the engines are different every year since 98.
Another consideration is that the '99-00 GT engines were built at Ford's Windsor plant. The '01-02 engines are built at the Romeo engine plant. I understand there were several changes made to the engines themselves along with the change of manufacturing locations. It's also worth noting that there was a change in the design of the front pulleys from 99 to 00, that's why a supercharger kit for a 99 won't fit a 00. So technically the engines are different every year since 98.
Black Sunshine does have a lot more power than mine does. And no power adder. I had the privilege of driving it one night in Houston and let me tell you, the hauling ass was sweet. I'm a 13.9 guy myself and it definately would've smoked the **** out of my car.
I raced Sunshine when it was about a mid 13 car. Whoop me bad.
I raced Sunshine when it was about a mid 13 car. Whoop me bad.
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