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PostPosted: Tue Nov 27, 2018 9:46 am 
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Matt93SE wrote:
I looked at the Prod rules and built my S14 for STU.
the early models 89-91 (and up to 94 if you backdate the motor) have a single cam engine which is more of a 'Prod motor'. (same one they use in GT3, etc). It gets higher compression and a decent size cam. The DOHC engine they started running in 92 evidently scared people off, and you have to run near stock compression and the intake manifold suuuucks for making decent power. it's got a fat torque curve, but runs out of air quickly with the limited prep rules. with the factory intake, there's no way it can reliably surpass 200whp, which is needed at the insane weight they throw at it.

the SOHC engine gets a compression bump, more cam, etc, BUT the crank is bendy with its 1/2 counterweight design and the SOHC block is weak, so the thing flexes and likes to go on permanent vacation if spun more than 6000rpm on a regular basis. the DOHC engine in mine (still stock internals and ECU waiting on the STU ruleset to stop moving before I built anything) has been revving to 6800 since I started tracking it in 2005, and now has over 30,000 track miles on it. never had the head off the engine- only the usual gaskets and seals have been replaced, so it's stupid reliable in OEM trim-- it just doesn't make enough power for Prod!

regarding the weight, my '96 weighs about 2400lb with all factory body panels, bumper supports, glass, complete OEM wiring harness, dash cover as required by STU, and no driver (so 2650 race weight with organic ballast). if you did the basic bodywork parts and wiring harness cleanup as allowed in Prod you could likely get it to 2200 or so dry-- so you could certainly achieve a lower weight IF it was allowed.

the 15x7 wheels also hurt it, and many people have tried to get the CRB to move on that 15x7 size.. but since the car was built back in the day of the 15" wheel, nobody will budge on that rule.

it could really be a pretty decent car, but hobbled by the restricted factory intake manifold and the Prod ruleset for making enough power to compete at that weight. And with the "come race it and get beat for a season and then we'll think about it and still tell you no" mindset, its a car with the deck stacked against it from day 1.

You really don't know much about these engines... :)

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PostPosted: Tue Nov 27, 2018 10:05 am 
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Joe Harlan wrote:
I owned one for years.. Its not going to make enough power to even get close.. Sad too because its a great car. Car is also way to heavy for the factory brakes. So all in all its just not a good prod fit..

For the record, to the very best of my "off the top of my head memory" (which my wife will say is subject, at best), the PAC has yet to receive a "Please look at the EP DOHC S14 again, cause damn fatty!" letter during my 8 years of service.

As Ron alludes, one thing that you can pretty much call up Vegas and bet the house on, is that nothing will ever be done if no one even asks.

What if it was 12.0:1 & .500, like almost every other limited prep EP car? Still too heavy at 2600lbs? IMO, yeah, probably. Car is and always will be a torque monster, that will stop pulling like a freight train as the mph's climb.

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PostPosted: Tue Nov 27, 2018 11:09 am 
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What was the one that Grayson Upchurch ran years ago? Seemed pretty competitive then.

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PostPosted: Tue Nov 27, 2018 11:38 am 
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Yeah the brakes were one thing that I looked at and pretty much stopped figuring much further. Hard to stop a 2600lb race car with such tiny brakes. Of course my over arching brake proposal would fix that. :lol:

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PostPosted: Tue Nov 27, 2018 2:02 pm 
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kruck wrote:
Joe Harlan wrote:
I owned one for years.. Its not going to make enough power to even get close.. Sad too because its a great car. Car is also way to heavy for the factory brakes. So all in all its just not a good prod fit..

For the record, to the very best of my "off the top of my head memory" (which my wife will say is subject, at best), the PAC has yet to receive a "Please look at the EP DOHC S14 again, cause damn fatty!" letter during my 8 years of service.

As Ron alludes, one thing that you can pretty much call up Vegas and bet the house on, is that nothing will ever be done if no one even asks.

What if it was 12.0:1 & .500, like almost every other limited prep EP car? Still too heavy at 2600lbs? IMO, yeah, probably. Car is and always will be a torque monster, that will stop pulling like a freight train as the mph's climb.

Kevin, thank you. by the time the car was approved I had already headed to GTL... like most of us the time I have left will be spent racing not chasing a rule change in the hopes of getting a break to be competitive.. I will help anyone that wants to built one of these will real data on how to get to the target HP and suggest a weight that is real but with that in mind ill never build a car for the class. If i were to run EP I would by an existing front running platform that has already be worked out.

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PostPosted: Tue Nov 27, 2018 2:05 pm 
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Brett W wrote:
Yeah the brakes were one thing that I looked at and pretty much stopped figuring much further. Hard to stop a 2600lb race car with such tiny brakes. Of course my over arching brake proposal would fix that. :lol:
It can be done but you are buying parts every weekend...(caliper,rotors and pads for the front) Its really sad the platform is a great car with lots of aftermarket suppliers and interest from the younger market.

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PostPosted: Tue Nov 27, 2018 2:08 pm 
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ERVRCG wrote:
What was the one that Grayson Upchurch ran years ago? Seemed pretty competitive then.
The early car was classed much better and Grayson was a hell of a driver, Kemp the car owner gave the tech guys fits with some of the early LP suspension rules. so yes the car was very good but probably better than the rules of its time. I got the early car classed I 99 with the help of Nissan Motorsports and brought the first one to the runoffs that year with a customer.

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PostPosted: Tue Nov 27, 2018 4:36 pm 
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Joe Harlan wrote:
Matt93SE wrote:
I looked at the Prod rules and built my S14 for STU.
the early models 89-91 (and up to 94 if you backdate the motor) have a single cam engine which is more of a 'Prod motor'. (same one they use in GT3, etc). It gets higher compression and a decent size cam. The DOHC engine they started running in 92 evidently scared people off, and you have to run near stock compression and the intake manifold suuuucks for making decent power. it's got a fat torque curve, but runs out of air quickly with the limited prep rules. with the factory intake, there's no way it can reliably surpass 200whp, which is needed at the insane weight they throw at it.

the SOHC engine gets a compression bump, more cam, etc, BUT the crank is bendy with its 1/2 counterweight design and the SOHC block is weak, so the thing flexes and likes to go on permanent vacation if spun more than 6000rpm on a regular basis. the DOHC engine in mine (still stock internals and ECU waiting on the STU ruleset to stop moving before I built anything) has been revving to 6800 since I started tracking it in 2005, and now has over 30,000 track miles on it. never had the head off the engine- only the usual gaskets and seals have been replaced, so it's stupid reliable in OEM trim-- it just doesn't make enough power for Prod!

regarding the weight, my '96 weighs about 2400lb with all factory body panels, bumper supports, glass, complete OEM wiring harness, dash cover as required by STU, and no driver (so 2650 race weight with organic ballast). if you did the basic bodywork parts and wiring harness cleanup as allowed in Prod you could likely get it to 2200 or so dry-- so you could certainly achieve a lower weight IF it was allowed.

the 15x7 wheels also hurt it, and many people have tried to get the CRB to move on that 15x7 size.. but since the car was built back in the day of the 15" wheel, nobody will budge on that rule.

it could really be a pretty decent car, but hobbled by the restricted factory intake manifold and the Prod ruleset for making enough power to compete at that weight. And with the "come race it and get beat for a season and then we'll think about it and still tell you no" mindset, its a car with the deck stacked against it from day 1.

You really don't know much about these engines... :)


Not really, no. I called around to Jim Wolf, Rebello, Nissan Motorsports about 10 years ago asking questions more regarding a higher compression motor that would be STU legal, and the short answer was "don't bother with it unless you have a REALLY big bucket of money; and you still won't beat the other guys." so I quit looking at it. I brought the same up to Rick Kulach back at my licencing school, and his comments werent' much different. Nissan Motorsports was no longer supporting them in favor of the current models (like the 350/370), so they didn't give much effort into continuing developing them, and no contingency unless you raced something that was sold on the showroom floor. (Can't say I blame them, but that pissed off all of the 240/260/280Z, 200SX, 240SX, 300ZX guys..) Kulach and efforts of others have since brought contingency back to other nissans which is great, but there was no incentive from them for a while...

Back in the late 90s when they were running the DOHC engine in world challenge TC (I have the VTS around here somewhere for it), they were still required to run the stock intake manifold and throttle body, and were limited to around 220whp no matter what they did to the engine since the intake simply couldn't breathe. Given the realization it was going to take >250hp at 2600lbs to be competitive in STU, I quit looking at the KA and started trying to get the SR legalized. Fast forward about 6-7 years, and the SR20DET was allowed, but they stuck a -2mm restrictor on it vs. every other turbo car in the class. yet again the STAC's answer was "build it and lose and then we'll talk."
I don't have that kind of money to build a top-flight motor only to lose and then have to build another engine when they change the rules. Plus if I'm going to step into the ring, I at want to at least believe I have a snowball's chance in hell. not trying to build an overdog, I just don't want to be hobbled from the beginning with a target that I know isn't reachable.

ERVRCG wrote:
What was the one that Grayson Upchurch ran years ago? Seemed pretty competitive then.

That car is now here in Houston- Joel Schweers owns it and is a friend of mine. It is a ~90 model S13 coupe with the SOHC engine. Power-wise, it was competitive 10 years ago, but hasn't progressed since then and everyone else has gotten faster. so the car is no longer competitive without another round of redevelopment. The issue is that SOHC engine can't really rev well under the Prod ruleset- harmonics on the stock crank and block- with the ensuing crank flex- cause it to eat itself above 6500rpm. Even at 6500rpm rev limit, the windage scraper would 'self-clearance' against the rod bolts after a couple races if that tells you much of anything.. so they built that engine for mid range torque and quit bothering trying to rev it to the sky. I don't recall the exact power numbers he said he made, but it was in the 200+- range and less torque. aftermarket forged crank is an option with a full-prep motor.

However, the DOHC motor is much better in that regard. they can spin to 7500 relatively well when you reduce the clutch & flywheel mass and put a good crank damper on it (among other things) the DOHC blocks are also a bit stiffer than the SOHC versions and the head flows better IF you can get the air through the intake manifold. best I've seen on the factory intake was the ~220whp that was quoted to me by a Rebello guy when they were doing the world challenge motors. the long intake runners just aren't great for top end, but they do make good torque. The current guys that build these in non-SCCA stuff (I've seen some pretty impressive NASA builds) have seen 250hp+ with alternate intake and higher compression, and well over 400hp in turbo applications-- none of which apply to an LP Prod design..

Brakes on the car were not much of an issue according to Joel. He uses a tilton pedal setup, cryo treated stock rotors and replaces them every couple of races; the pads he's using are "NASRCAR short track" stuff- either PFC or Raybestos but I forget the compound. he says the pads haven't needed replaced since he started using them, but the rotors are wear items.
In my STU car, I put together some 2-pc 11.75" Coleman rotors and Superlite calipers. never had a problem with brakes at my ~150hp level and DOT tires. Hawk DTC-70 pads last 50+hrs per set. I have to rebuild master cylinders and calipers more often than I have to touch the friction parts because wilwood. (Next project is a Tilton 800-series pedal assembly).

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PostPosted: Tue Nov 27, 2018 4:57 pm 
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Matt93SE wrote:
Joe Harlan wrote:
Matt93SE wrote:
I looked at the Prod rules and built my S14 for STU.
the early models 89-91 (and up to 94 if you backdate the motor) have a single cam engine which is more of a 'Prod motor'. (same one they use in GT3, etc). It gets higher compression and a decent size cam. The DOHC engine they started running in 92 evidently scared people off, and you have to run near stock compression and the intake manifold suuuucks for making decent power. it's got a fat torque curve, but runs out of air quickly with the limited prep rules. with the factory intake, there's no way it can reliably surpass 200whp, which is needed at the insane weight they throw at it.

the SOHC engine gets a compression bump, more cam, etc, BUT the crank is bendy with its 1/2 counterweight design and the SOHC block is weak, so the thing flexes and likes to go on permanent vacation if spun more than 6000rpm on a regular basis. the DOHC engine in mine (still stock internals and ECU waiting on the STU ruleset to stop moving before I built anything) has been revving to 6800 since I started tracking it in 2005, and now has over 30,000 track miles on it. never had the head off the engine- only the usual gaskets and seals have been replaced, so it's stupid reliable in OEM trim-- it just doesn't make enough power for Prod!

regarding the weight, my '96 weighs about 2400lb with all factory body panels, bumper supports, glass, complete OEM wiring harness, dash cover as required by STU, and no driver (so 2650 race weight with organic ballast). if you did the basic bodywork parts and wiring harness cleanup as allowed in Prod you could likely get it to 2200 or so dry-- so you could certainly achieve a lower weight IF it was allowed.

the 15x7 wheels also hurt it, and many people have tried to get the CRB to move on that 15x7 size.. but since the car was built back in the day of the 15" wheel, nobody will budge on that rule.

it could really be a pretty decent car, but hobbled by the restricted factory intake manifold and the Prod ruleset for making enough power to compete at that weight. And with the "come race it and get beat for a season and then we'll think about it and still tell you no" mindset, its a car with the deck stacked against it from day 1.

You really don't know much about these engines... :)


Not really, no. I called around to Jim Wolf, Rebello, Nissan Motorsports about 10 years ago asking questions more regarding a higher compression motor that would be STU legal, and the short answer was "don't bother with it unless you have a REALLY big bucket of money; and you still won't beat the other guys." so I quit looking at it. I brought the same up to Rick Kulach back at my licencing school, and his comments werent' much different. Nissan Motorsports was no longer supporting them in favor of the current models (like the 350/370), so they didn't give much effort into continuing developing them, and no contingency unless you raced something that was sold on the showroom floor. (Can't say I blame them, but that pissed off all of the 240/260/280Z, 200SX, 240SX, 300ZX guys..) Kulach and efforts of others have since brought contingency back to other nissans which is great, but there was no incentive from them for a while...

Back in the late 90s when they were running the DOHC engine in world challenge TC (I have the VTS around here somewhere for it), they were still required to run the stock intake manifold and throttle body, and were limited to around 220whp no matter what they did to the engine since the intake simply couldn't breathe. Given the realization it was going to take >250hp at 2600lbs to be competitive in STU, I quit looking at the KA and started trying to get the SR legalized. Fast forward about 6-7 years, and the SR20DET was allowed, but they stuck a -2mm restrictor on it vs. every other turbo car in the class. yet again the STAC's answer was "build it and lose and then we'll talk."
I don't have that kind of money to build a top-flight motor only to lose and then have to build another engine when they change the rules. Plus if I'm going to step into the ring, I at want to at least believe I have a snowball's chance in hell. not trying to build an overdog, I just don't want to be hobbled from the beginning with a target that I know isn't reachable.

ERVRCG wrote:
What was the one that Grayson Upchurch ran years ago? Seemed pretty competitive then.

That car is now here in Houston- Joel Schweers owns it and is a friend of mine. It is a ~90 model S13 coupe with the SOHC engine. Power-wise, it was competitive 10 years ago, but hasn't progressed since then and everyone else has gotten faster. so the car is no longer competitive without another round of redevelopment. The issue is that SOHC engine can't really rev well under the Prod ruleset- harmonics on the stock crank and block- with the ensuing crank flex- cause it to eat itself above 6500rpm. Even at 6500rpm rev limit, the windage scraper would 'self-clearance' against the rod bolts after a couple races if that tells you much of anything.. so they built that engine for mid range torque and quit bothering trying to rev it to the sky. I don't recall the exact power numbers he said he made, but it was in the 200+- range and less torque. aftermarket forged crank is an option with a full-prep motor.

However, the DOHC motor is much better in that regard. they can spin to 7500 relatively well when you reduce the clutch & flywheel mass and put a good crank damper on it (among other things) the DOHC blocks are also a bit stiffer than the SOHC versions and the head flows better IF you can get the air through the intake manifold. best I've seen on the factory intake was the ~220whp that was quoted to me by a Rebello guy when they were doing the world challenge motors. the long intake runners just aren't great for top end, but they do make good torque. The current guys that build these in non-SCCA stuff (I've seen some pretty impressive NASA builds) have seen 250hp+ with alternate intake and higher compression, and well over 400hp in turbo applications-- none of which apply to an LP Prod design..

Brakes on the car were not much of an issue according to Joel. He uses a tilton pedal setup, cryo treated stock rotors and replaces them every couple of races; the pads he's using are "NASRCAR short track" stuff- either PFC or Raybestos but I forget the compound. he says the pads haven't needed replaced since he started using them, but the rotors are wear items.
In my STU car, I put together some 2-pc 11.75" Coleman rotors and Superlite calipers. never had a problem with brakes at my ~150hp level and DOT tires. Hawk DTC-70 pads last 50+hrs per set. I have to rebuild master cylinders and calipers more often than I have to touch the friction parts because wilwood. (Next project is a Tilton 800-series pedal assembly).


Amazing that stock crank turns 8k all day long, 3 valve engines have valve terrain issues at 8k, I built a long rod radial sedan 4 valve for my RS car..13:1 and 275hp on the factory manifold..
Rick Kulatch actually asked me if I would consider building an S14 EP car early in his program.
Now to correct your facts a little Blocks and Cranks are almost identical other than the S14 blocks have piston squirters built into them. the limitations on rpm is in the head for the 3 valve and almost unlimited on the 4 valve. This is a very reliable design for racing.
220whp is around flywheel.. pretty decent but not gonna happen at 10:1..

Ill gladly help support someone that wants to ask for help with this car. I am just to late in life to try to build it and wait for the changes.

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PostPosted: Tue Nov 27, 2018 8:41 pm 
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Joe Harlan wrote:
Amazing that stock crank turns 8k all day long, 3 valve engines have valve terrain issues at 8k, I built a long rod radial sedan 4 valve for my RS car..13:1 and 275hp on the factory manifold..
Rick Kulatch actually asked me if I would consider building an S14 EP car early in his program.
Now to correct your facts a little Blocks and Cranks are almost identical other than the S14 blocks have piston squirters built into them. the limitations on rpm is in the head for the 3 valve and almost unlimited on the 4 valve. This is a very reliable design for racing.
220whp is around flywheel.. pretty decent but not gonna happen at 10:1..

Ill gladly help support someone that wants to ask for help with this car. I am just to late in life to try to build it and wait for the changes.

Interesting that you have considerably different results than other guys that have employed the big name Nissan builders and dumped piles of cash into being told vastly different info and seeing different results. I'm sure Joel would be much happier if the bill for that engine build included results like yours...

I've pretty much lost my interest in building another SCCA car, particularly for Prod... other series have rulesets that allow less expensive and more reliable ways to make the same speed. for $2500 in parts and a week's worth of labor, I can have a VQ35 in the S14 and make more power on pump gas, with factory stock reliability... makes a fun endurance and track day car because pump gas and cheap consumables.
I also want to get into a tube frame car as well for the tinkering abilities- would love a tube frame 240SX or an RX7... but there's very little for GT3 competition around here. GT2 has a decent participation rate, but they're big and $$. I don't expect the current GTL guy(s) to be racing more than a couple more years so I'd be out driving by myself.
Prod has a better participation rate, but the magic is just lost, especially when you know you'll never win a Majors unless Reynolds doesn't show.

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Matt Blehm
Houston Region
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