Converter too tight??
02-02-2015, 01:04 PM
#21
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Even with skinny front tires I don't have an issue with locking up brakes, front or rear. I use Baer's dual caliper kit. With a 15-0 9.5 I can hold over 4400 rpm with them. I now have a super tight 10" converter that will hold 3700 rpm with them.
If someone was worried about locking up the rear tires you could install a prop valve on the system.
I still think something is off with this brake system. Are they vacuum brakes? If so, is there a good working check valve between the engine and brakes? A single caliper rear disc should easily old this converter to 3000+
If someone was worried about locking up the rear tires you could install a prop valve on the system.
I still think something is off with this brake system. Are they vacuum brakes? If so, is there a good working check valve between the engine and brakes? A single caliper rear disc should easily old this converter to 3000+
02-02-2015, 03:33 PM
#22
Even with skinny front tires I don't have an issue with locking up brakes, front or rear. I use Baer's dual caliper kit. With a 15-0 9.5 I can hold over 4400 rpm with them. I now have a super tight 10" converter that will hold 3700 rpm with them.
If someone was worried about locking up the rear tires you could install a prop valve on the system.
I still think something is off with this brake system. Are they vacuum brakes? If so, is there a good working check valve between the engine and brakes? A single caliper rear disc should easily old this converter to 3000+
If someone was worried about locking up the rear tires you could install a prop valve on the system.
I still think something is off with this brake system. Are they vacuum brakes? If so, is there a good working check valve between the engine and brakes? A single caliper rear disc should easily old this converter to 3000+
Not many dual-calipers systems that keep the emergency brake intact. The ones that do are like 1200-1500.
02-02-2015, 03:35 PM
#23
I bought my TCI transbrake for $450 I think. Installed it myself. I don't know what you would spend on a dual caliper rear setup, but $450 is not a bad price. Is there some reason you don't want a transbrake? I am not going to say it is a requirement for an auto turbo car, but it is really close to one. Helps out a ton.
02-02-2015, 04:00 PM
#24
My car also has SN95 brakes front and rear on it and they will for sure push pretty easy. I know with my personal car, it was about 2600-2700. With the 2 step a little more, but that was it. It was not until I added the sloppy transbrake that I could go higher.
02-02-2015, 07:54 PM
#25
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These brakes are notoriously weak from the factory from what I've read and experienced. These are vac brakes and the check valve is there but I need to check it. I think I need to go through the whole thing b/c honestly the car doesnt stop as good as I think it should despite all new brakes around including EBC race-type pads on the front. I'm going to replace the booster/master cyl and all the brake hoses too as the pedal is way too soft.
Not many dual-calipers systems that keep the emergency brake intact. The ones that do are like 1200-1500.
Not many dual-calipers systems that keep the emergency brake intact. The ones that do are like 1200-1500.
We can also look at your converter data when you make some WOT passes with the boost cranked up where you intend to run it at. It's possible to loosen it some depending on how it works. I just feel the brakes are the main issue.
02-02-2015, 08:09 PM
#26
I tried a few aftermarket pads on my aft brakes. They needed too much heat in them to get grabby. Cheapo basic organic pads worked best for "cold holding power" on my setup.
You can also weld an extension on the brake pedal for more leverage and/or rig up an electric vacuum pump on the brake system.
You can also weld an extension on the brake pedal for more leverage and/or rig up an electric vacuum pump on the brake system.
02-02-2015, 08:21 PM
#27
My pedal pretty much bottoms-out when I stand on it, which can't be good but the car DOES stop decent. Not great, decent.
Question here, is it preferable to build boost with the brakes or trans brake vs the 2 step? I'm getting some boost now on the 2 step as mentioned earlier but the rpms have to be kept to around 2600 and the engine wants to punch me in the face.
Question here, is it preferable to build boost with the brakes or trans brake vs the 2 step? I'm getting some boost now on the 2 step as mentioned earlier but the rpms have to be kept to around 2600 and the engine wants to punch me in the face.
02-02-2015, 09:16 PM
#28
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My pedal pretty much bottoms-out when I stand on it, which can't be good but the car DOES stop decent. Not great, decent.
Question here, is it preferable to build boost with the brakes or trans brake vs the 2 step? I'm getting some boost now on the 2 step as mentioned earlier but the rpms have to be kept to around 2600 and the engine wants to punch me in the face.
Question here, is it preferable to build boost with the brakes or trans brake vs the 2 step? I'm getting some boost now on the 2 step as mentioned earlier but the rpms have to be kept to around 2600 and the engine wants to punch me in the face.
Even with great brakes, the suspension is all loaded up with the brakes trying to hold it back. I'd hate to know I had to race without a trans brake.
04-23-2015, 06:37 PM
#30
Wanted to bring this up after getting some datalogs with the new converter - PTC 9.5". At 11-12psi. Wondering if this should be loosened a bit. Old converter I would pull more fuel in high gear. Here, its seems to flatten a bit on top, but not sure if its ok. Slip calculates to 4-5% on top speed runs.
1-2 shift 6400-4700 = 1700 drop
2-3 shift 6186-4762 = 1424 drop
The 2-3rd drop was a little more than usual, most times its around 1200.
Seem ok?
1-2 shift 6400-4700 = 1700 drop
2-3 shift 6186-4762 = 1424 drop
The 2-3rd drop was a little more than usual, most times its around 1200.
Seem ok?
04-24-2015, 07:57 AM
#33
Get some progressive boost control going. With out it, I’d blow my 29X12 slicks off at 12lbs with a 3.10 gear (on the street). Guys making twice my power level are hooking on the street… with 275 drag radials and progressive control.
Last edited by Forcefed86; 04-24-2015 at 01:53 PM.
04-24-2015, 12:29 PM
#34
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If your going to keep the power low I would loosen the converter some but if your ever planning on turning the boost up the converter may end up to loose. Best all around idea would be a transbrake. You will get use to the shifting while street driving...its still better than a stick car.
04-25-2015, 01:31 AM
#36
I'll chime in.
I made my first passes with my new PTC last weekend.
On the footbrake, I can get to 3500 rpm which is slightly higher than my previous ATI converter.
Down track, the PTC slip shows 5%. The ATI was 10%.
This is exactly what I wanted.
One problem it created was it slips so much less than my old converter it caused my auto 1-2 shift to happen at 5700 instead of 6300 like before. My 5.3 likes revs so it killed mph. We were also running into a 15-20 mph headwind which hurt mph as well.
With more runs and turning up the two step to something over 3000 (2700 rpm now) I'm sure the car will set new records. And I'll certainly have room to up the boost. I'm at 15 psi now.
Ron
I made my first passes with my new PTC last weekend.
On the footbrake, I can get to 3500 rpm which is slightly higher than my previous ATI converter.
Down track, the PTC slip shows 5%. The ATI was 10%.
This is exactly what I wanted.
One problem it created was it slips so much less than my old converter it caused my auto 1-2 shift to happen at 5700 instead of 6300 like before. My 5.3 likes revs so it killed mph. We were also running into a 15-20 mph headwind which hurt mph as well.
With more runs and turning up the two step to something over 3000 (2700 rpm now) I'm sure the car will set new records. And I'll certainly have room to up the boost. I'm at 15 psi now.
Ron
04-25-2015, 09:19 AM
#39
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Efficient is good not just tight. In Ronssnova's example the ati even though it was "tighter" at stall it was still slipping more than the ptc was down the track. This is assuming that the boost/power was the same with both converters.