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Hap Waldrop
Yoda
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Re: PVGP new pics
Matthew are you going to use the 1275 or 1500?
Matthew are you going to use the 1275 or 1500?
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PVGP BeaverRun
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Matthew E. Herd
Jedi Warrior
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Re: PVGP new pics
I plan (eventually) on using a 1275, as they're more bulletproof in the bottom end, and have more available parts selections. They may suffer on the porting a bit, but that's not a huge issue, as they're still fairly potent. As an aside, Midgets and Sprites aren't actually listed on the same line of Street Prepared rules, meaning they can't be updated/backdated between the two cars. I know this is absurd, but perhaps a letter is in order ...
I plan (eventually) on using a 1275, as they're more bulletproof in the bottom end, and have more available parts selections. They may suffer on the porting a bit, but that's not a huge issue, as they're still fairly potent. As an aside, Midgets and Sprites aren't actually listed on the same line of Street Prepared rules, meaning they can't be updated/backdated between the two cars. I know this is absurd, but perhaps a letter is in order ...
Hap Waldrop
Yoda
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Re: PVGP new pics
Matt, from understanding your rules, no head porting, with the exception of the 1" gasket porting in SCCA road racing
"limited prep" motors we're in the same delima atleast on cylinder heads. When LP rules came out, we all knew the need for a cherry head cores that flowed the most stock would become an issue. What alot of found was the head core shift was the magic deal. On some heads, both pre smog 12G940s and smog heads 12G1316s we found that some heads had upward core shift which made the humps in the ports where the valve guides protrudes through to be the deciding factor. A good upward core shift head will flow a good 8 CFM per port more tham a bad example. They are very noticable when inspecting head cores with the valves removed, you will see little or no hump in the exahaust ports and smaller humps in the intake ports. This year I'm helping two former SCCA HP national champoions make the switch to the limited prep 1275 for the the full prep 948s they were formally ran, Randy Canfield and Ron Bartell, we flowed a ton of 1275 heads on my flowbench and the top two became thier heads. I continue to flow 1275 heads to find good cores for the LP engines. So now you know what to look for on a 1275 head and I can flow it for you to confirm it is a good flowing head when you find a suitable core or possibly provide you with a good flowing core. Hope this helps.
Matt, from understanding your rules, no head porting, with the exception of the 1" gasket porting in SCCA road racing
"limited prep" motors we're in the same delima atleast on cylinder heads. When LP rules came out, we all knew the need for a cherry head cores that flowed the most stock would become an issue. What alot of found was the head core shift was the magic deal. On some heads, both pre smog 12G940s and smog heads 12G1316s we found that some heads had upward core shift which made the humps in the ports where the valve guides protrudes through to be the deciding factor. A good upward core shift head will flow a good 8 CFM per port more tham a bad example. They are very noticable when inspecting head cores with the valves removed, you will see little or no hump in the exahaust ports and smaller humps in the intake ports. This year I'm helping two former SCCA HP national champoions make the switch to the limited prep 1275 for the the full prep 948s they were formally ran, Randy Canfield and Ron Bartell, we flowed a ton of 1275 heads on my flowbench and the top two became thier heads. I continue to flow 1275 heads to find good cores for the LP engines. So now you know what to look for on a 1275 head and I can flow it for you to confirm it is a good flowing head when you find a suitable core or possibly provide you with a good flowing core. Hope this helps.
Matthew E. Herd
Jedi Warrior
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Re: PVGP new pics
Wow, good stuff. Don't expect to take on this project for a few years yet, but it's really good to know. I'm looking for 'every little bit helps.'
The wheel and tire package will be something on the order of 13x8" with 225/45R13's ... pretty absurd on a spridget, eh? /ubbthreads/images/graemlins/smile.gif
I'm also curious how low we could get the suspension. I'm looking for a minimum of 1.5 to 2" bump travel. You can modify bump stops and change springs or add spacers. I figure if you eliminate the bump stop and its' perch on the rear axle (judging by my 1500) that you could drop the car as much as 4 inches from stock. Fenders can be cut outboard of the wheel mounting surface to accommodate the modification. I'm less familiar with the acceptable modifications up front, but I (personally) only have trouble with hitting the stops in the rear, even though the front is lowered 1.5" or so. However, lowering the car that much almost certainly requires an in-tunnel exhaust. I assume some of us have experience with these?
Wow, good stuff. Don't expect to take on this project for a few years yet, but it's really good to know. I'm looking for 'every little bit helps.'
The wheel and tire package will be something on the order of 13x8" with 225/45R13's ... pretty absurd on a spridget, eh? /ubbthreads/images/graemlins/smile.gif
I'm also curious how low we could get the suspension. I'm looking for a minimum of 1.5 to 2" bump travel. You can modify bump stops and change springs or add spacers. I figure if you eliminate the bump stop and its' perch on the rear axle (judging by my 1500) that you could drop the car as much as 4 inches from stock. Fenders can be cut outboard of the wheel mounting surface to accommodate the modification. I'm less familiar with the acceptable modifications up front, but I (personally) only have trouble with hitting the stops in the rear, even though the front is lowered 1.5" or so. However, lowering the car that much almost certainly requires an in-tunnel exhaust. I assume some of us have experience with these?
RobSelina
Jedi Warrior
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Re: PVGP new pics
[ QUOTE ]
I'm curious if anyone knows about working on optimizing ignition timing for more power. I think that may yield a few odd horsepower that would help keep up with those darned VW's.
[/ QUOTE ]
Something I'm curious about too.
This link is interesting:
https://www.teglerizer.com/mgstuff/lucastuning.pdf
The most important info is on page two. Maximum power is achieved when maximum pressure is achieved 17-20-degrees ATDC.
If we knew how long it took to burn up the fuel/air mixture in our combustion chamber it would be a relatively simple calculation to get the rough ignition curve for a vehicle. I'm sure it's more complicated than that, but I bet this would be a close calculation, and I bet it would be different than stock!
[ QUOTE ]
I'm curious if anyone knows about working on optimizing ignition timing for more power. I think that may yield a few odd horsepower that would help keep up with those darned VW's.
[/ QUOTE ]
Something I'm curious about too.
This link is interesting:
https://www.teglerizer.com/mgstuff/lucastuning.pdf
The most important info is on page two. Maximum power is achieved when maximum pressure is achieved 17-20-degrees ATDC.
If we knew how long it took to burn up the fuel/air mixture in our combustion chamber it would be a relatively simple calculation to get the rough ignition curve for a vehicle. I'm sure it's more complicated than that, but I bet this would be a close calculation, and I bet it would be different than stock!
Hap Waldrop
Yoda
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Re: PVGP new pics
Get rid of the rubber bump stops in the rear entirely, all you have to do then is get spacers to go in between the axles and springs and longer U bolts, on the front Winners Circle sells lower race springs then to get even lower you can space down the spring pad on the control arm with spacers and longer bolts. Alot of SCCA race cars are running ride heights of 2" or less measured at the rocker panel seam, but if you get this low you need a thru the tunnel exahust header and they are only avaialable for 1275s. The 13 x 8 on the later model car with closed top rear fender won't work, about 5.5" is the best you can hope for, maybe a 6" wheel with major back spacing or cut the fender and go with flares, but then you will need offset or 1" composite rear springs to clear on the inboard side. Rob you are working with a car (MG Midget) which is one of the all time most popular cars ever raced in SCCA road racing, if you can think up something, there is already someone making it. You need to get in touch with a Spriget racers in your area and look at a club racing car, you'll get quite a education, I believe Bruce ( for the life of me can't remember his last nmae right now) lives in NM, also I've got a good friend in Prescott AZ. who club road races Midgets, he's in the wheel business and can probably help you with your wheel needs. Rob, you're traveling down a well traveled path and no need to re invent the wheel, it's already invented. Have you visited my website that would be good start?
Get rid of the rubber bump stops in the rear entirely, all you have to do then is get spacers to go in between the axles and springs and longer U bolts, on the front Winners Circle sells lower race springs then to get even lower you can space down the spring pad on the control arm with spacers and longer bolts. Alot of SCCA race cars are running ride heights of 2" or less measured at the rocker panel seam, but if you get this low you need a thru the tunnel exahust header and they are only avaialable for 1275s. The 13 x 8 on the later model car with closed top rear fender won't work, about 5.5" is the best you can hope for, maybe a 6" wheel with major back spacing or cut the fender and go with flares, but then you will need offset or 1" composite rear springs to clear on the inboard side. Rob you are working with a car (MG Midget) which is one of the all time most popular cars ever raced in SCCA road racing, if you can think up something, there is already someone making it. You need to get in touch with a Spriget racers in your area and look at a club racing car, you'll get quite a education, I believe Bruce ( for the life of me can't remember his last nmae right now) lives in NM, also I've got a good friend in Prescott AZ. who club road races Midgets, he's in the wheel business and can probably help you with your wheel needs. Rob, you're traveling down a well traveled path and no need to re invent the wheel, it's already invented. Have you visited my website that would be good start?
Hap Waldrop
Yoda
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Re: PVGP new pics
Not that I know of, but I recall his last name now, Bruce Gurney. He used to race a neon orange Midget in F Production, may still for all I know, I'm pretty sure he was at the Mid Ohio runoffs last year. Bruce used to work for Huffaker as well.
Not that I know of, but I recall his last name now, Bruce Gurney. He used to race a neon orange Midget in F Production, may still for all I know, I'm pretty sure he was at the Mid Ohio runoffs last year. Bruce used to work for Huffaker as well.
Matthew E. Herd
Jedi Warrior
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Re: PVGP new pics
Hap,
Keep in mind this is a future early car that I was planning on cutting the fenders to stick those wheels out. I don't know about the GCR, but Solo rules for Street Prepared don't require that the tires are within the flares. I've already got 5" wheels on my 1500, and you're right, they JUST fit! I didn't get offset springs, but the rule is that you must maintain stock mounting points. I was also going to go with the in tunnel exhaust, but heard they make the tunnels quite warm (not that it really matters). Since solo courses tend to have fairly flat parking lots, you can usually get away with 2" from the seam on the rockers to the ground almost all the time. I currently have (with a regular exhaust, 2 1/4" diameter with flanges besides) less than 3" ground clearance, and I never have trouble on course, only over speed bumps and in my stone driveway!
The reason to modify the bump stop pedestal would be to retain as much travel as possible while getting the car down too. I've already got the moss lowered rear springs and 400 lb/in springs in the front, so I'm familiar with the typical performance items. As I said before, I can get away with 13x8" wheels because the rules say you can modify the hood and fenders outboard of the wheel mounting surface (brake drum/rotor) with flares. They also say you don't need to keep the wheels within the fenders, so as long as I can still turn, I can stick them out 4" if I so desire. I can also use a very small backspace in the rear to avoid spring clearance issues.
I'm aware that this will make the car difficult to turn (from a steering wheel perspective) but it should dramatically increase the track and the amount of rubber on the road. Track isn't restricted in SP, so if they make a wider wheel and DOT legal tire, we can use them (luckily, 225mm in a 13" wheel is the limit).
Hap,
Keep in mind this is a future early car that I was planning on cutting the fenders to stick those wheels out. I don't know about the GCR, but Solo rules for Street Prepared don't require that the tires are within the flares. I've already got 5" wheels on my 1500, and you're right, they JUST fit! I didn't get offset springs, but the rule is that you must maintain stock mounting points. I was also going to go with the in tunnel exhaust, but heard they make the tunnels quite warm (not that it really matters). Since solo courses tend to have fairly flat parking lots, you can usually get away with 2" from the seam on the rockers to the ground almost all the time. I currently have (with a regular exhaust, 2 1/4" diameter with flanges besides) less than 3" ground clearance, and I never have trouble on course, only over speed bumps and in my stone driveway!
The reason to modify the bump stop pedestal would be to retain as much travel as possible while getting the car down too. I've already got the moss lowered rear springs and 400 lb/in springs in the front, so I'm familiar with the typical performance items. As I said before, I can get away with 13x8" wheels because the rules say you can modify the hood and fenders outboard of the wheel mounting surface (brake drum/rotor) with flares. They also say you don't need to keep the wheels within the fenders, so as long as I can still turn, I can stick them out 4" if I so desire. I can also use a very small backspace in the rear to avoid spring clearance issues.
I'm aware that this will make the car difficult to turn (from a steering wheel perspective) but it should dramatically increase the track and the amount of rubber on the road. Track isn't restricted in SP, so if they make a wider wheel and DOT legal tire, we can use them (luckily, 225mm in a 13" wheel is the limit).
Hap Waldrop
Yoda
Offline
Re: PVGP new pics
Offset rear spring use stock pick up points as do the composite rear springs. With that much rubber on the road you probably want to go with double bearing rear hubs as well or you'll start breaking axles.
Offset rear spring use stock pick up points as do the composite rear springs. With that much rubber on the road you probably want to go with double bearing rear hubs as well or you'll start breaking axles.
Matthew E. Herd
Jedi Warrior
Offline
Re: PVGP new pics
Yeah. Unfortunately (even though it's not a performance advantage) that may or may not be rules legal ... It's a gray area.
Yeah. Unfortunately (even though it's not a performance advantage) that may or may not be rules legal ... It's a gray area.