Doug904
Sponsor
- Joined
- March 30, 2001
- Messages
- 533
- Reaction score
- 1
- City, State
- Jasper, Alabama
- Year, Model & Trim Level
- 2005 Roush GT
Well Brian Mckelvey remade his intake track and did away with that factory airbox. It definatly made a difference.
We started out with a new baseline of 283rwhp at 12:2 a/f ratio but then disaster struck the first time, the coolant temp sendor for the guage blew apart? The reasoning, he had taken it apart before and replaced the clip that holds it in with a different style clip, the clip didn't hold to say the least, look like ole' faithful spewing coolant, ahhaaa.
Well we got that fixed for then by bending the new clip in a bit and made sure it was good before the following run. I also went in and removed some timing up top, not because it was pinging but because I was scared we had blown a head gasket and that was actually pressure in the cooling system. We made the next run and it went great, 286rwhp. Wow, even by taking a few degree's of timing out it still had a gain, I think it was because the first run it got hot quickly when the coolant went and also got the blower belt wet.
For the next run we added in some more timing above what I had removed by a few degree's and I richened it up a bit too. We got the best yet, 293rwhp and 321 rwtq. This was great, and still absolutly no pinging or knock sensor activation.
Finally I went in and added just a couple of more degree's above 4000 rpm's because it was getting a little high in the timing department and we made the final pass, the power fell off up top and when we were letting it decel after the run it just shut off.
Well, after reviewing the fuel and spark curves that I had datalogged I thought it may have been some belt slippage, a wet belt equals a slipping belt on a blower, so we got some belt dressing out and sprayed it. When we went to start the engine that's when we heard it. It sounded like a car spinning over without a timing belt, if you have ever heard one of those. It spun over very quickly like it had no compression. We did finally get it to start but it was bucking and running horribly, it also had a metallic sound in the engine up high. That was it for the dyno runs.
We got it back to his house by way of trailor and even started it up and pulled it into the garage. Pulled the valve covers and found the rear tensioner on the passenger's side, of course it's the hard one, has collasped. We are doing some more investigation on why this happened and what we can do to prevent it in the future.
Either way this happened at only 6,100 rpm's so if you're thinking about winding your 4.0 up very far past this mark then you may wanna reconsider. Yes, we had a good strain on it with the HP and TQ numbers but still the timing chain really isn't a high stress component.
Here's the graph on the 293 run...
Thanks, Doug.
We started out with a new baseline of 283rwhp at 12:2 a/f ratio but then disaster struck the first time, the coolant temp sendor for the guage blew apart? The reasoning, he had taken it apart before and replaced the clip that holds it in with a different style clip, the clip didn't hold to say the least, look like ole' faithful spewing coolant, ahhaaa.
Well we got that fixed for then by bending the new clip in a bit and made sure it was good before the following run. I also went in and removed some timing up top, not because it was pinging but because I was scared we had blown a head gasket and that was actually pressure in the cooling system. We made the next run and it went great, 286rwhp. Wow, even by taking a few degree's of timing out it still had a gain, I think it was because the first run it got hot quickly when the coolant went and also got the blower belt wet.
For the next run we added in some more timing above what I had removed by a few degree's and I richened it up a bit too. We got the best yet, 293rwhp and 321 rwtq. This was great, and still absolutly no pinging or knock sensor activation.
Finally I went in and added just a couple of more degree's above 4000 rpm's because it was getting a little high in the timing department and we made the final pass, the power fell off up top and when we were letting it decel after the run it just shut off.
Well, after reviewing the fuel and spark curves that I had datalogged I thought it may have been some belt slippage, a wet belt equals a slipping belt on a blower, so we got some belt dressing out and sprayed it. When we went to start the engine that's when we heard it. It sounded like a car spinning over without a timing belt, if you have ever heard one of those. It spun over very quickly like it had no compression. We did finally get it to start but it was bucking and running horribly, it also had a metallic sound in the engine up high. That was it for the dyno runs.
We got it back to his house by way of trailor and even started it up and pulled it into the garage. Pulled the valve covers and found the rear tensioner on the passenger's side, of course it's the hard one, has collasped. We are doing some more investigation on why this happened and what we can do to prevent it in the future.
Either way this happened at only 6,100 rpm's so if you're thinking about winding your 4.0 up very far past this mark then you may wanna reconsider. Yes, we had a good strain on it with the HP and TQ numbers but still the timing chain really isn't a high stress component.
Here's the graph on the 293 run...
Thanks, Doug.
