Interesting , I never felt the GM brakes had an issue , now Jeep brakes on the other hand .....
My 1973 K10 Chevy Cheyenne
- Thread starter Chris
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Interesting , I never felt the GM brakes had an issue , now Jeep brakes on the other hand .....
Interesting , I never felt the GM brakes had an issue , now Jeep brakes on the other hand .....
They aren’t the worst, but with a single piston design, they do leave a little something to be desired. These calipers are supposed to work with the factory rotors and being dual piston. I would think that there would be a noticeable increase in breaking performance. The question, however, though is will they work with the factory wheels. If not, it’s not worth it to me.
I know that on motorhome chassis's there wasn't any difference in braking performance between the GM single piston and Ford dual piston . I was in charge of a 80 motorhome rental fleet plus new motorhome sales and service . The class A GM P-30 would lock the front end at 65 m.p.h. with 245/70 R 19.5 tires .
Honestly , the only brake issues were on the Dodge chassis . They used a phenolic single piston caliper that the piston would cock in the bore and not release.
The phenolic piston was supposed to keep brake heat away from the brake fluid , sounds good but was a issue in real life.
If needed, you can put a 1 ton GM caliper on that truck. The external dimensions are the same, but the piston is larger. I did that on my C10, along with the matching hydroboost, and it stops well.
The GM code for them is JB7.
The GM code for them is JB7.
My 80 K-20 , 8600 GVW , C6P has that as well that as well . The rear drums are 13" , must be included in the C6P option . There isn't any RPO on the Spid showing any brake options.
Thanks, I'll look into this. Probably cheaper than the Wildwood kit anyways!
The JB7 caliper will give you 7.81 square inches of area vs. 6 for the 2 piston Wilwood. Maybe that's why I don't have any brake complaints....
The JB7 caliper will give you 7.81 square inches of area vs. 6 for the 2 piston Wilwood. Maybe that's why I don't have any brake complaints....
I suppose that would do it! I'm going to be doing a brake job on it at some point (ball joints too) so I'll grab some of these calipers! Thanks for the info guys, this is great!
You may need to match the master cylinder to those calipers. I'm not sure how they would perform with one made for the smaller pistons.
My whole setup is duplicating a 79 P30 van chassis motorhome, minus the dually rear drums.
My whole setup is duplicating a 79 P30 van chassis motorhome, minus the dually rear drums.
I figured that might be the case. Any idea what the P/N is on the master? Or what specific vehicle can I look up on RockAuto to find the right one?
Got the dash completed today:
The Dakota Digital gauges look awesome. They're even better at night as they're LED backlit.
Finally, I've got to figure out this fresh air vent door situation. My factory one was rotted so I ordered a replacement. Unfortunately the replacements have some slight differences as you'll see in the photos below:
Here's what the factory door looks like on my '73 on the right. The replacement door is on the left. Notice the differences?
And here's a reminder of what the interior looked liked when I bought it:
After all of this the last thing to do is replace the carpet with the correct slate blue color and then I'm going to install my new slate blue pillar trim pieces and a vinyl slate blue headliner.
Lastly, I need to do something about these seats. I want them to match so I need to find some slate blue skins for them. Someone installed later model seats in it which I appreciate more since the drivers seat can move forward and backwards independently of the passenger seat.
The Dakota Digital gauges look awesome. They're even better at night as they're LED backlit.
Finally, I've got to figure out this fresh air vent door situation. My factory one was rotted so I ordered a replacement. Unfortunately the replacements have some slight differences as you'll see in the photos below:
Here's what the factory door looks like on my '73 on the right. The replacement door is on the left. Notice the differences?
And here's a reminder of what the interior looked liked when I bought it:
After all of this the last thing to do is replace the carpet with the correct slate blue color and then I'm going to install my new slate blue pillar trim pieces and a vinyl slate blue headliner.
Lastly, I need to do something about these seats. I want them to match so I need to find some slate blue skins for them. Someone installed later model seats in it which I appreciate more since the drivers seat can move forward and backwards independently of the passenger seat.
Looks much better ! For your brake application on Rockauto a 79 P-30 forward control chassis in a Union City StepVan would be a start. @Claytone may have better specifics. The K-10 is much better than a late model Mustang in my opinion .
On a slightly different note, I'm ditching the Holley Sniper EFI setup and going with an Edelbrock Pro-Flo 4 which I scored for a great deal.
I'm told that the direct injection (or whatever the technical term is) is a lot better than throttle body injection as far as drivability goes. The Sniper works great, but I notice it isn't as smooth as I'd like and sometimes it even stumbles. Ostensibly this is a known feature of TBI.
Anyways, we'll see how it does with the Pro Flo 4, but from what I've read people seem to say it's a worthy upgrade over TBI.
I'm told that the direct injection (or whatever the technical term is) is a lot better than throttle body injection as far as drivability goes. The Sniper works great, but I notice it isn't as smooth as I'd like and sometimes it even stumbles. Ostensibly this is a known feature of TBI.
Anyways, we'll see how it does with the Pro Flo 4, but from what I've read people seem to say it's a worthy upgrade over TBI.
While if I had a choice I would take the Pro-Flo over the Sniper , Don't expect the drivability to be night and day better. TBI was used by OEM's for many years without driveability issues . $ 2400.00 is the going rate for a SBC . I'm curious to see what you think after the install.
I’m curious as well. I really don’t have any issues with a sniper other than the fact that it can hesitate sometimes and stumble on occasion. From what I’ve read the pro flow is better for liability and makes things much smoother. Not sure how true that is, but that’s what the reviews say online. I know what you’re saying, though. They did use throttle body injection on a number of vehicles for a number of years.
Just curious , can you program the Sniper to give more " accelerator pump shot " ? More fuel may have helped with the stumble condition on tip in.
I’ll need to look into that but I’m sure it’s possible. It slightly hesitates off the like when you give it throttle. It’s not much, maybe just a second but it’s annoying to say the least.
More power isn’t what I’m after, just a smoother and more crisp throttle delivery. That’s what the Pro Flo is supposed to be good for.
Not direct injection. The Pro Flo is sequential fuel injection. Here's a primer on fuel injection systems, mainly in chronological order of usage on production vehicles:
- Throttle Body Injection - one or two injectors that inject fuel upstream of the individual runners, and the timing of the injections is not relative to intake valve opening - like a computer-controlled carb.
- Central Port Injection - GM used this weird system in the 90s. It had a single injector and then tubes with poppet valves to deliver the fuel just upstream of the intake valves. I've never even seen this system (only read about it), but it was a cool idea that predated multiple injectors. Cheap ECUs (PCMs in the TJ world) relegated this one to the dustbin.
- Multi-port Injection (MPI) - has one injector per cylinder, injecting just upstream of the intake valves. However, firing wasn't necessarily coordinated with valve opening. So, the first MPI systems were like having a computer-controlled carb for each cylinder.
- Bank-fire or Batch-fire Injection - a type of MPI system where injectors for multiple cylinders fire together, timed per revolution, but not with intake valve opening.
- Sequential Fuel Injection - the one that "stuck" in the production vehicle world (mostly, see #6 below). Each cylinder has an injector just upstream of the intake valve, and it's timed to the valve opening.
- Direct Injection - Mainly for emissions, this system is a special type of sequential fuel injection. It puts the injection point directly in the combustion chamber. Injectors must be much more durable since they experience the full pressure and heat of combustion. The fuel pressure is also much higher due to combustion pressures. The fuel pump has to pump fuel into the cylinder while combustion pressures are rising, and the fuel pressure has to be higher than the combustion pressure in order for fuel to flow out the injector.
So, there you have it. A brief history of fuel injection. I happened to start my automotive career with carbs and end just as DI was in development, so I got to experience many of those systems. Back in the late 90s, Orbital patented direct injection for two-stroke engines. Two-strokes are very dirty (emissions-wise) engines, and the EPA was really tightening up two-stroke emissions requirements. DI was seen as a way to get there, and many companies, Polaris included, bought rights to Orbital's patents.
In the snowmobile world, Ski-doo and Arctic Cat ended up going with DI. Polaris, on the other hand, developed their CleanFire engines, which are considered semi-direct-injection. They inject the fuel into the transfer port on the engine (two strokes don't use valves). I've been out of the snow machine world for about a decade, but as far as I know, Polaris is still using semi-direct-injection. They've somehow stayed ahead of the tightening EPA restrictions, which is a good thing, in my opinion. When I was there over twenty years ago, we all thought DI was our future. It wasn't! (not, yet, anyway)
Here's a conversation with ChatGPT about my setup:
https://chatgpt.com/share/6994ca2f-6874-8005-ada6-18e1a222d94f
What I find interesting is that it's describing all of my symptoms perfectly. This is a very high horsepower race engine and at times with the Sniper setup it seems like it misses a beat, hunts for idle, etc.
It's not so much that it doesn't work (it does), but it's not as clean and crisp as an LS swap for instance. Supposedly the Pro Flo 4 will fix that which is what I'm after. I want it to feel a bit more like driving a LS in regard to consistency with idle, throttle response, etc.
https://chatgpt.com/share/6994ca2f-6874-8005-ada6-18e1a222d94f
What I find interesting is that it's describing all of my symptoms perfectly. This is a very high horsepower race engine and at times with the Sniper setup it seems like it misses a beat, hunts for idle, etc.
It's not so much that it doesn't work (it does), but it's not as clean and crisp as an LS swap for instance. Supposedly the Pro Flo 4 will fix that which is what I'm after. I want it to feel a bit more like driving a LS in regard to consistency with idle, throttle response, etc.
Correct, I was looking for the correct terminology and mistakenly called it direct injection which is what's on the newer LS engines (which I don't like).
Sequential fuel injection is what I'm after where each cylinder has an injector and the fuel is shot directly into the intake valve which eliminates cylinders fighting for fuel when it's been dumped in from the throttle body.
I've read a lot of LS tuners don't like the DI that comes on the newer LS engines either. A lot are reverting to sequential fuel injection (which is probably why it's stuck around for so long, it just works).
I'm sure I could have pieced together my own system to run, but I got a really good price on this Pro Flo 4 and the convenience factor is a bonus as well.