NASA ST4 build
#21
Mud_Duck I did and I didnt haha. The driveshaft was most of it and it vastly improved when i went to the second design of the shaft with the cv joint on the transmission end. Still had a slight high frequency vibration at about 110 mph that I had been trying to sort with pinion angle changes, up until the rear diff housing broke both ears off at the last event, destroyed the driveshaft as well. I'll post some pics of the destruction later.
So now i'm having the drive shaft shop make a custom one for it that hopefully will cure the issues, the old one was a cheaply made one and not high speed balanced. I modified/reinforced the rear end housing as well this time, a little over kill but I don't want that to happen again as I'm lucky the driveshaft didn't puncture the fuel tank, it did beat the hell out of it along with several other items when it came loose.
The tire vibrations were a large amount of what I was feeling as well, solved that by mounting them with just a little water, no soap or lube. As for the motor being a vibration issue, no. The engine is smooth wound up, little buzzy just above idle but overall it feels like the 1.6. I do have the balance shafts deleted which i'm sure is what I am feeling around idle and low rpm but everything else is purely driveline related.
So now i'm having the drive shaft shop make a custom one for it that hopefully will cure the issues, the old one was a cheaply made one and not high speed balanced. I modified/reinforced the rear end housing as well this time, a little over kill but I don't want that to happen again as I'm lucky the driveshaft didn't puncture the fuel tank, it did beat the hell out of it along with several other items when it came loose.
The tire vibrations were a large amount of what I was feeling as well, solved that by mounting them with just a little water, no soap or lube. As for the motor being a vibration issue, no. The engine is smooth wound up, little buzzy just above idle but overall it feels like the 1.6. I do have the balance shafts deleted which i'm sure is what I am feeling around idle and low rpm but everything else is purely driveline related.
#22
Well after a long shitty year of very little racing, this season is starting off pretty good! End of the season last year we broke the aluminum diff housing, both ears broken, which caused the drive shaft to come loose and damage quite a few things. So a little reinforcement to the diff, pinion mounting and a improved driveshaft were up and running again.
And no I didn't re-use the broken housing, that is a new one that I modified.
Here is a fun vid of race one on Saturday at WWTR Gateway this past weekend, I had a great time with a decent field of 7 ST4 cars and we had about 33 race cars total so much passing to be had for all! I am very pleased with how this little package is starting to come together as I get the issues worked out. I started back of the field since I missed qualifying due to a throttle body failing on me. I am replacing it with a mechanical one to make sure that does not happen again as that really pissed me off!
Lots of time left in the car and myself, camber needs to be closer to -4.5* front and -3.5 rear so I'm going to have to change up some suspension bits to get that amount. Nose opening needs narrowed up to reduce drag, need to move the air filter out of the engine bay as its still about 15 to 20* above ambient. It all adds up!
Hope you enjoy, I know I did!
And no I didn't re-use the broken housing, that is a new one that I modified.
Here is a fun vid of race one on Saturday at WWTR Gateway this past weekend, I had a great time with a decent field of 7 ST4 cars and we had about 33 race cars total so much passing to be had for all! I am very pleased with how this little package is starting to come together as I get the issues worked out. I started back of the field since I missed qualifying due to a throttle body failing on me. I am replacing it with a mechanical one to make sure that does not happen again as that really pissed me off!
Lots of time left in the car and myself, camber needs to be closer to -4.5* front and -3.5 rear so I'm going to have to change up some suspension bits to get that amount. Nose opening needs narrowed up to reduce drag, need to move the air filter out of the engine bay as its still about 15 to 20* above ambient. It all adds up!
Hope you enjoy, I know I did!
#25
Well..... knock on wood, I believe I have solved the final gremlin of this swap as the car ran great all weekend and allowed the driver to screw up plenty of times and come back in the end! Over the past couple seasons we kept running into throttle body failures one of which I believe killed the driver in the ecu which lead me down the path to the fix. We swapped in a new ecu at gateway last month and the car ran the best it ever has but in the end another throttle issue arose. When we got home from the event I removed the throttle body on the car and tore it apart along with the other failed units and found that the teeth inside, which are plastic, had multiple teeth knocked off. They looked liked my sons rc cars pinion gears when the lash is set wrong. So this happend.......
No more DBW and wish I had all the time back from fighting this stupid thing!
So after changing to mechanical throttle things are how they should be and the car is consistent! We went to Hallet this past weekend and did very well with another win after I got my head out of my *** on saturday. Feels pretty good to be able to concentrate on setup and driver now, I haven't turned a shock **** or made suspension adjustments on this car in two seasons so we have a ton of speed left in the car plus were underpowered by a little so some engine modifications are on the menu now.
Started in last place due to me deciding to 360 during the prequal race but we came back and took the win!
Here is the vid of the finals race.
No more DBW and wish I had all the time back from fighting this stupid thing!
So after changing to mechanical throttle things are how they should be and the car is consistent! We went to Hallet this past weekend and did very well with another win after I got my head out of my *** on saturday. Feels pretty good to be able to concentrate on setup and driver now, I haven't turned a shock **** or made suspension adjustments on this car in two seasons so we have a ton of speed left in the car plus were underpowered by a little so some engine modifications are on the menu now.
Started in last place due to me deciding to 360 during the prequal race but we came back and took the win!
Here is the vid of the finals race.
Thread
Thread Starter
Forum
Replies
Last Post
OGRacing
Build Threads
55
08-24-2016 05:13 AM