Next years goal... 750 true RWHP
10-07-2012, 02:45 PM
#76
Three Wheelin'
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Sid, what doyou estimate the build cost on one of your short blocks is?
I have tried following the build, but you are INSANE (i sued that in a complimenting way). As soon as you make a little more power, you crank it up more. You also have a pretty big turbo from my understanding.
Taking a step back, what do you estimate that your short block would do (HP) with a reasonably sized turbo? What about pump gas? This means something around 15-17psi in denver and a turbo sized for street.
I have tried following the build, but you are INSANE (i sued that in a complimenting way). As soon as you make a little more power, you crank it up more. You also have a pretty big turbo from my understanding.
Taking a step back, what do you estimate that your short block would do (HP) with a reasonably sized turbo? What about pump gas? This means something around 15-17psi in denver and a turbo sized for street.
10-07-2012, 07:10 PM
#78
Race Car
Thread Starter
I'm thinking the head or cam is limiting me. Like I said, after 6300 it is going rich for no reason. The airflow is steady at 4.57-4.6v and the boost is steady. The IDC isn't changing., so my conclusion is there is a restriction.
The turbo may be at its limit. I wasn't measuring ait.
It wants to keep revving I just didn't see the point.
The ONLY tuning we did was on the last two runs. We leaned it out on the second to last and added 4 degrees over 6200 on the final along with 2 psi more. I needed a few more runs really.
I'm not sure if the hp curve will rise at the top rpms even at higher boost.
Gonna try my bigger cam next or the bigger tb.
However, I'm going to race it this week in this configuration and see if I can get 130 mph.
After that I'll be using a dyno to see changes.
What are your thoughts given the above info?
The turbo may be at its limit. I wasn't measuring ait.
It wants to keep revving I just didn't see the point.
The ONLY tuning we did was on the last two runs. We leaned it out on the second to last and added 4 degrees over 6200 on the final along with 2 psi more. I needed a few more runs really.
I'm not sure if the hp curve will rise at the top rpms even at higher boost.
Gonna try my bigger cam next or the bigger tb.
However, I'm going to race it this week in this configuration and see if I can get 130 mph.
After that I'll be using a dyno to see changes.
What are your thoughts given the above info?
10-08-2012, 11:58 AM
#82
Rainman
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Any thoughts of going back to a twin-scroll turbine to pick up some earlier torque?
Would there be any point of experimenting with reverse-flow cooling on the new engine with only 0.400" of block open for circulation?
Would you sell the "old" shortblock instead of blowing it up when the big motor is done?
Would there be any point of experimenting with reverse-flow cooling on the new engine with only 0.400" of block open for circulation?
Would you sell the "old" shortblock instead of blowing it up when the big motor is done?
10-08-2012, 12:17 PM
#83
Racer
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Any thoughts of going back to a twin-scroll turbine to pick up some earlier torque?
Would there be any point of experimenting with reverse-flow cooling on the new engine with only 0.400" of block open for circulation?
Would you sell the "old" shortblock instead of blowing it up when the big motor is done?
Would there be any point of experimenting with reverse-flow cooling on the new engine with only 0.400" of block open for circulation?
Would you sell the "old" shortblock instead of blowing it up when the big motor is done?
10-08-2012, 12:22 PM
#84
Race Car
Thread Starter
Spencer, the dyno is deceptive as to torque down low. If you look at my dyno vs many 3.0's I'm hitting 400lb ft about 500 rpms earlier. Just looked at the actual time it takes to go from 300-500tq and it's less than 2 seconds. On the street with slight smount of tire spin it really instant. So in other words I don't want any more low end torque.
I will try to keep this short in tact, but I probably will hang onto it for a spare.
I will try to keep this short in tact, but I probably will hang onto it for a spare.
10-08-2012, 03:31 PM
#86
Rocket Scientist
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What dyno was that on, Sid?
If you look at the chart I posted on Reutterwerk, you'll see the car continues to make power well into redline of 7200. The main difference between your setup and that setup is displacement size, which obviously has no effect on power to redline, and the cam, which does.
If you look at the chart I posted on Reutterwerk, you'll see the car continues to make power well into redline of 7200. The main difference between your setup and that setup is displacement size, which obviously has no effect on power to redline, and the cam, which does.
10-08-2012, 04:05 PM
#87
Race Car
Thread Starter
Derek it is a dynojet. Idk where another bar and is around here. I did get to see a dyno of a real 968 turbo rs and I'm quite a bit higher. That RS had a nice flat torque curve but was limited to 400 hp.
Rob, I think that might work for better low end, but through my research, the final turbo size is what dictates the final power. Which is what I want to improve. I'm not concerned with more bottom end as I stated earlier. I already waste tires at a rapid pace as it is. I don't want to make it worse.
Rob, I think that might work for better low end, but through my research, the final turbo size is what dictates the final power. Which is what I want to improve. I'm not concerned with more bottom end as I stated earlier. I already waste tires at a rapid pace as it is. I don't want to make it worse.
10-08-2012, 05:59 PM
#88
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Sid, The intake ports on a "true" 968 turbo RS are tiny. They would suggest an rpm limit to maybe 7000 max. So, yes, a very flat tq curve but still hp to redline.
10-08-2012, 06:21 PM
#89
Race Car
Thread Starter
The guy had it there the weds prior. I wish I could have seen the car. I guess it's owned by a collector here in boulder where I work. I know the company he owns as I used to have them as a client when I had the printing co. Sounds like he has quite the collection. I guess they're flying in the original driver to run it at high plains raceway soon.
I wish I knew more about the heritage , but it sounds interesting. 1 of 4or 5???
I wish I knew more about the heritage , but it sounds interesting. 1 of 4or 5???
10-08-2012, 06:35 PM
#90
Drive-by provocation guy
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Patrick, it's 2.85L
The stroke, reciprocating weight, the way I did my combustion chamber design, my port work, the bigger bore, the exhaust. It all adds up plus the BMW TB and a few other items.
It's a pretty well sorted combo I think. Considering this is right off the road and not fully tuned.
I really have to thank Josh for getting me this far!!!
The stroke, reciprocating weight, the way I did my combustion chamber design, my port work, the bigger bore, the exhaust. It all adds up plus the BMW TB and a few other items.
It's a pretty well sorted combo I think. Considering this is right off the road and not fully tuned.
I really have to thank Josh for getting me this far!!!