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Discussion Starter #1
There are lots of cams out there and I don't have a feel for cams on turbo engines. I've looked at the cam cards from BrianCrower, Crower Cams, GSC, Kelford, and HKS.

Note, that some specs are at 1mm (about .040") and others are at .050".

I'm thinking of a pump gas engine, maybe VVTi for a car that is really just for the street and 'dyno racing'.

What do you have, how is it on the street, what would you change. If you have the info, it would be great if you had the specs and the settings it was installed at. In the specs I seem most have the exhaust open at 50°-60° BBDC and closed right around TDC with intakes opening right around exhaust closing with little, no, or even negative overlap.

Your insights would be helpful.
 

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2JZ-GTE's don't seem to be nearly as cam-sensitive as many other engines. Either that or we're fortunate and have very consistently good camshaft upgrades. I've ran or installed/worked with a lot of the common camshafts out there HKS's, GSC's, BC's especially. I haven't seen many Crower (as opposed to BC) Kelford or Titan cams, though.

A lot of the classic Japanese tuning houses offered cams that substantially advanced intake valve opening to reduce dynamic compression, and thus stretch out what they can do with higher boost on their RON100 fuel. (HKS 272's and HKS280's, JUN, Blitz, etc)
This also added lag, so a lot of folks see them as 'old technology' when it's simply a different approach to cam tuning to meet their needs in the Japanese market.

For a pump gas engine with VVTi and a not-fuckhuge single turbo I'd just get the VVTi-friendly GSC S1's and call it a day.
With VVTi you can tune out any lope or bad idle or lack of low end and it'll pull like a freight train up top. Given those advantages you can also run 9.0-9.5:1 static compression and pump gas to ~18psi without much fuss so long as you've got a good standalone that controls VVTi well - and a good tune of course.

I've also seen great results with the Tomei and HKS "264" profiles they offer for VVTi engines.
 

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For a pump gas engine with VVTi and a not-fuckhuge single turbo I'd just get the VVTi-friendly GSC S1's and call it a day.
With VVTi you can tune out any lope or bad idle or lack of low end and it'll pull like a freight train up top. Given those advantages you can also run 9.0-9.5:1 static compression and pump gas to ~18psi without much fuss so long as you've got a good standalone that controls VVTi well - and a good tune of course.
I sure am glad to hear that, for my current build I bought GSC S1 Cams for my VVTI motor.
 

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With VVTi you can tune out any lope or bad idle or lack of low end and it'll pull like a freight train up top. Given those advantages you can also run 9.0-9.5:1 static compression and pump gas to ~18psi without much fuss so long as you've got a good standalone that controls VVTi well - and a good tune of course.
I know there are a lot of good ECUs out now but which one you think handles the VVTI engines better specially for someone who is going to buy it new.
 

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I know there are a lot of good ECUs out now but which one you think handles the VVTI engines better specially for someone who is going to buy it new.
Any standalone is only as good as its tuner, but IMHO any good tuner that honestly knows wtf is up and knowing you want the latest-greatest is going to recommend an AEM Infinity, Motec M130/M150, Syvecs S6, or Haltech Elite 2500. If you really want the ultimate a Motec can't be beat, but buckle up for a $6k+ engine management package and tune.

There's a few older standalones that can work well, but don't have all the latest advanced features and/or current manufacturer support. This IMHO includes the AEM V2, ProEFI, Haltech PS2000, and Link G4.

But there's a few standalones that are really outdated (AEM V1, Hydra) or just plain suck (literally every piece of shit Megasquirt ever fucking made) and you should avoid those.


If you have an honestly good tuner local to you that knows Supras and is *known* to have tuned other Supras (as in, other Supra owners tell you he tuned their car) then I would follow his recommendation. This will often be something like an AEM V2, etc which reflects the tuners experience. If he's tuned other VVTi 2JZ-GTE cars on that ECU with good results, you can bank on having good results.

Now, if you don't have a tuner like that anywhere near you, I'd recommend making arrangements to have a remote tune from a reputed remote-tuner that does Supras. Basically you'll make a dyno appointment and your tuner will remote into your tuning laptop via the internet and do all the tuning work for you while the local tuning house guy just drives the car on the dyno. Works like a charm especially if everything is actually sorted out in the car and there aren't any hardware or wiring issues (there almost ALWAYS are, no matter how nicely built the car is) in which case you correct them as you can and often that results in a second tuning appointment and remote session.

But for a good tune from someone that's well reputed in the Supra world, that's money well spent. Plus it can lead to some funny stories, like one I heard about Vlad @ National Speed completing a remote tune on a customer's AEM Infinity Supra while Vlad was literally on the toilet. :rofl:
 

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Any standalone is only as good as its tuner, but IMHO any good tuner that honestly knows wtf is up and knowing you want the latest-greatest is going to recommend an AEM Infinity, Motec M130/M150, Syvecs S6, or Haltech Elite 2500. If you really want the ultimate a Motec can't be beat, but buckle up for a $6k+ engine management package and tune.
Thank you sir, There are a lot of tuners and shops within 50/100 miles of me. And most of them actually tuned some crazy 2jzs and some of the members here have their cars to prove it but as you said just have to talk to them and go from there.

But in your personal opinion you think AEM Infinity is better unit than ProEFI ?
 

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.

But in your personal opinion you think AEM Infinity is better unit than ProEFI ?
I’m curious as well. I am doing my “research” on stand alones, and I am looking at proefi 128. Leaving tuner aside, why do you say AEM infinity is better? They look very similar to me.
 

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Discussion Starter #8
I had a piggyback thread, but really need a standalone thread.

First there has to be an application. Is this a track car? A drag car? A street car?

Notes on ECUs

Haltech has a drag racing focus. They have the 2500, 2500T, 2500 + REM. They just introduced a new CPU for carbureted drag cars.

Syvecs is made by Life, which was founded after Pectel was sold to Cosworth. It is used on Lamborghinis, GT-Rs, etc.; that is, people where the money is less of an object. It includes a lot of features standard, includes cruise control (req DBW), a pretty advanced traction control, paddle shifting, etc...in the box. Garage Whifbiz uses it for their BMW DCT transmission conversion. Life and Pectel could also be used.

AEM is a strange puppy. The software is developed by EngineLab, the software is the same. But lots of features for the price, especially logging.

Motec has and doesn't have everything. Some setups are less supported and some of it requires third party plug-ins. Some stuff is in options packs.

Not sure where ProEFI fits in, but the feature set seems smaller.

Back to Cams

In the racing I've done, the big issue is how fast you can open the valve and getting the right valve lift for the head. The cam may be 242/248 or 256/260 depending on the tracks, but a Ford .875 solid lifter can be more aggressive than a Chevy .842, roller lifters can handle more aggressive ramps than solid lifters, and even the rollers are constrained by the diameter of the camshaft and the roller.

The Supra has a big 1.2" diameter bucket and target lift is probably only about 10.0mm-10.3mm. That is a bit deceptive, because on the exhaust it is pretty much done by BBTC...that is only about 50°-60° for the exhaust valve to do its thing. The Kelford "C" and the GSC S1 are pretty similar, 228/232 at 1mm with about 9.9mm of lobe lift. The HKS 272 is roughly equivalent, 232/232 at 1mm with 9.3mm lobe lift; similar duration but much less area under the curve. BC doesn't have anything equivalent...their stage 3 is 228/232 at .050 (probably 232/236 at 1mm) with less lift. Note that BC's biggest came is 232/232 at .050, but with 11.5mm lift. That probably gets the valve off the seat pretty fast. The Crower "02" is 230/232 at .050 (234/236 at 1mm?) but with over 10.5mm lift on the exhaust. Their '03' is 232/234 with 10.8mm lift. I think the 02 exhaust is the 03 intake.

It is very hard to distinguish these small differences on the street or dyno. One may idle a little rougher, one may make a bit more power. Tune counts in both cases. But a build is the sum of a lot of little pieces. Some lower intake temps. Some improve combustion. Some increase flow. Others reduce friction. 10hp here. 20hp there. 5hp somewhere else and it all adds up.

This thread's first response was leaning toward the 228/232 at 1mm with about 9.9mm of lobe lift GSC. The question might be how much bigger the cams can go before part throttle response and a rough idle make it less suited for street use. Is 228/232 (smaller than an HKS 272, but with more area under the curve) the limit?
 

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Discussion Starter #9
One more question:

With your cam, what rev limit do you use and what valve spring do you use to achieve it?

I noticed the GSC has a behive and 2 different rate conical springs. Kelford the beehive and a standard. Others seem to mostly be standard singular and double springs.

http://www.enginelabs.com/features/editorials-opinions/tech5-billy-godbold-of-comp-cams-explains-conical-springs/

https://www.power-division.com/gsc-power-division-conical-valve-spring-with-ti-retainer-for-the-toyota-2jz.html

 

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Springs in the JZ engines aren't really a worry. You can pretty much use whatever you want. Until you get to crazy levels of boost (+50psi).

Most people just pick a brand they like.

Same with cams.
 

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I’m in a similar situation. Been looking at cams for my s366, built auto, high stall, 3:26 geared car. I’m leaning towards the gsc s1 or the bc264 or bc272 both with a single spring upgrade. The shorter duration of the bc 264 should make the midrange pretty stout and they have more lift than the hks 272( as reference to a popular cam choice). So it should make for a strong cam. The gsc s1 is ideal I think but at the price I’m not sure the benefits outweigh the gains? Although the specs in duration seem to be close to more of a 272 duration cam. I’m also not sure how a 272 duration cam would react to a high stall auto with taller than normal gearing. Should I go for more midrange punch to pull the gearing? Or go for top end and hope the high stall can still spool the turbo and pull the gearing without it being too lazy? What’s everyone’s thoughts?
 

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Springs in the JZ engines aren't really a worry. You can pretty much use whatever you want. Until you get to crazy levels of boost (+50psi).

Most people just pick a brand they like.

Same with cams.

I come from a place where lifter/bucket diameter, valve train mass and stiffness, and valve spring stiffness and life are the limiting factors. The goal was always to pop the valve off the seat and open as quickly as possible. On the intake, the closing was also fast. In oval racing there is no shifting, the cars come off the corner (in my class) in the mid- to hi- 4k rpm range depending on traffic/racing situations and top out at an intake limited just over 7k rpm.

The more aggressive the cam, the more power with smaller duration. The burden on the valve springs was huge. It is common to check the spring stiffness on the head regularly and replace the valve springs on an assembled engine in the car. Valve springs that are pushed get hot. Some come with coatings and surface finishes to reduce stresses and aid cooling. My SBC valve covers have valve spring oilers to cool the valve springs, tubes that spray oil on the valve springs, The cam lobes were from a design to push the limits of the Chevy .842 lifter; they had a more aggressive lobe for the Ford .875 lifter.

A Honda K20 and F20c have the same bore and stroke as a 2JZ. However, they have bigger valves and more lift, 11mm-12mm.

As a result, I'm having a bit of trouble understanding the limits on Supra cams. I'm confused by the low lift. With the very low valvetrain mass (no rocker at all and smallish valves). I would have expected more lift with the shorter durations since the low overlap of turbo cams and the lower compression of forced induction engines provides more latitude as the valve chases the piston down the hole on the intake stroke.

I would have hoped for a cam with specs like 224/228 @ .050 with 11mm of lift and an aggressive profile that banged the valve off the seat. The GSC S1/Kelford T/V202-C are nearly identical in specs 228/[email protected] with 9.9 cam lift, and it seems anything bigger makes for rough running. I'm guessing the lack of lobes that would seem more appropriate for road racing/oval racing is because this engine is used for mega-power, not mega-flexibility and mega-midrange coming off the corners.

Another question is why the Supertech sodium-cooled exhaust valve isn't widely used...or is it?

The rev limit is another question. The Honda S2000 F20c came from the factory with a 9k rev limit. K24s with rocker arms, a 99mm stroke and 55mm mains regular go 8k-9k and often 10k or more. The Supra has 62mm mains and shorter stroke and direct acting valve train...why are 8k numbers more common than 9k numbers. To get 1851 hp, Real Street rev'd to 9k. In that dyno pull/max power environment why not 10k?

The Supertech and Manley intake valves have undercut stems for increased flow at lower lifts. Based on my biases and what I've learned the +1 Supertech valves with the sodium cooled/Iconel exhaust, the softer GSC conical spring, and the GSC S1 seems a good combo a primarily street/pump gas engine. The Kelford T/V-202C cams would be identical.

A few hundred dollars one way or another is a rounding error this at performance level on this old a car. A lot of work goes into making the changes and there are lots of pieces that can break and be far more expensive to fix.
 

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I come from a place where lifter/bucket diameter, valve train mass and stiffness, and valve spring stiffness and life are the limiting factors. The goal was always to pop the valve off the seat and open as quickly as possible. On the intake, the closing was also fast. In oval racing there is no shifting, the cars come off the corner (in my class) in the mid- to hi- 4k rpm range depending on traffic/racing situations and top out at an intake limited just over 7k rpm.

The more aggressive the cam, the more power with smaller duration. The burden on the valve springs was huge. It is common to check the spring stiffness on the head regularly and replace the valve springs on an assembled engine in the car. Valve springs that are pushed get hot. Some come with coatings and surface finishes to reduce stresses and aid cooling. My SBC valve covers have valve spring oilers to cool the valve springs, tubes that spray oil on the valve springs, The cam lobes were from a design to push the limits of the Chevy .842 lifter; they had a more aggressive lobe for the Ford .875 lifter.

A Honda K20 and F20c have the same bore and stroke as a 2JZ. However, they have bigger valves and more lift, 11mm-12mm.

As a result, I'm having a bit of trouble understanding the limits on Supra cams. I'm confused by the low lift. With the very low valvetrain mass (no rocker at all and smallish valves). I would have expected more lift with the shorter durations since the low overlap of turbo cams and the lower compression of forced induction engines provides more latitude as the valve chases the piston down the hole on the intake stroke.

I would have hoped for a cam with specs like 224/228 @ .050 with 11mm of lift and an aggressive profile that banged the valve off the seat. The GSC S1/Kelford T/V202-C are nearly identical in specs 228/[email protected] with 9.9 cam lift, and it seems anything bigger makes for rough running. I'm guessing the lack of lobes that would seem more appropriate for road racing/oval racing is because this engine is used for mega-power, not mega-flexibility and mega-midrange coming off the corners.

Another question is why the Supertech sodium-cooled exhaust valve isn't widely used...or is it?

The rev limit is another question. The Honda S2000 F20c came from the factory with a 9k rev limit. K24s with rocker arms, a 99mm stroke and 55mm mains regular go 8k-9k and often 10k or more. The Supra has 62mm mains and shorter stroke and direct acting valve train...why are 8k numbers more common than 9k numbers. To get 1851 hp, Real Street rev'd to 9k. In that dyno pull/max power environment why not 10k?

The Supertech and Manley intake valves have undercut stems for increased flow at lower lifts. Based on my biases and what I've learned the +1 Supertech valves with the sodium cooled/Iconel exhaust, the softer GSC conical spring, and the GSC S1 seems a good combo a primarily street/pump gas engine. The Kelford T/V-202C cams would be identical.

A few hundred dollars one way or another is a rounding error this at performance level on this old a car. A lot of work goes into making the changes and there are lots of pieces that can break and be far more expensive to fix.
It's not in the cylinder head, it's in the bottom end. The factory wet sump oil pump really starts falling off on performance around 8300-8500rpm even when upgraded, and piston velocities on 3.4L strokers get harsh in that same area, with the factory 3.0L stroke not far behind.
I've always wanted to do a shimless bucket/bigass cam build with a very short runner intake manifold with ITB's or a properly sized big throttle, and put a dry sump 3.0L under it with a custom long rod setup using stroker-kit wristpin heights to get the rod:stroke ratio more ideal for high RPM. I believe such a build could haul strong to 11k+, but little is known about how far the stock crank could be pushed when knife edged, etc or whether a new billet crank from Winberg, etc would be required. Billet mains would be used, of course.

Also, Arnout, head mad scientist at Suprasport Europe, has prototyped a custom billet 2JZ head that basically puts a K-motor's VTEC and big valves and vastly superior port designs etc all on top of a 2JZ. On a cost-is-no-object build for high RPM, I'd certainly go for that. I don't know of any that are currently installed in driving street cars at the moment, though.
 

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It's not in the cylinder head, it's in the bottom end. The factory wet sump oil pump really starts falling off on performance around 8300-8500rpm even when upgraded, and piston velocities on 3.4L strokers get harsh in that same area, with the factory 3.0L stroke not far behind.
I've always wanted to do a shimless bucket/bigass cam build with a very short runner intake manifold with ITB's or a properly sized big throttle, and put a dry sump 3.0L under it with a custom long rod setup using stroker-kit wristpin heights to get the rod:stroke ratio more ideal for high RPM. I believe such a build could haul strong to 11k+, but little is known about how far the stock crank could be pushed when knife edged, etc or whether a new billet crank from Winberg, etc would be required. Billet mains would be used, of course.

Also, Arnout, head mad scientist at Suprasport Europe, has prototyped a custom billet 2JZ head that basically puts a K-motor's VTEC and big valves and vastly superior port designs etc all on top of a 2JZ. On a cost-is-no-object build for high RPM, I'd certainly go for that. I don't know of any that are currently installed in driving street cars at the moment, though.
Why don't we see lots of modified replacement oil pumps? For the K24, multiple firms offer modified pumps, usually S2000 pumps, and also dry sumps (Dailey for 4Piston, Barnes from DragCartel. 4P's description of their modified pump: "The stock K20 oil pump is a great piece for up to 9,000 rpm bursts. Beyond 9,000 the stock oil pump starts to cavitate. Continuous duty at high rpm and in endurance racing with very high oil temperature, this cavitation can be catastrophic. Our ported pump will allow continuous use above 9,000 rpm, and we have run the pump beyond 11,000 rpm with great success."

I've read turbo instructions that warn of crankcase pressurization reducing oil flow through the turbo. Is the Supra immune from this? I'd imagine dry sumping would have significant power gains, especially on pump gas/knock limited engines where the boost can't be increased. In oval racing dry sumps are often banned, receive a weight penalty, or are restricted in vacuum. Here, it seems a rare enhancement inspite of its relatively marginal cost (similar to a single turbo kit or stroker kit).

There are K24s with up to 110mm stroke. 99mm is OEM. The K20, F20c/F22c, and K24 differ primarily in deck height: 8.35 in, 8.82 in, and 9.11 in. The 2JZ, with an 8.62 in deck height and max 96mm stroke (94mm more common) already has a short stroke. Beyond that, a straight six is inherently better balanced than an a 4-cylinder, the 2JZ has significantly larger main bearings and more crank/rod journal overlap (stroker K24s often have none), the bucket valve system with shorter valves has more stiffness and less mass than the rocker (and OEM rocker with hydraulic VTEC) of the K24.

IMHO rod geometry, combustion characteristics, valve-to-piston clearance, and cylinder filling are large impacts of rod/stroke ratio and far more abstract, esoteric, and not understood. Pro Stock cars, limited to a 4bbl carb, use low deck heights and 1.5 rod/stroke ratios to get short runner lengths. They go to 11+k with large pistons and pins. K24's are at 1.53. The 96mm stroker is 1.47.

If stresses from rpm were an issue there would be more lightening: titanium valves, titanium rods (both std on the Z06 and included in some built K24s), lightweight pistons (4Piston's 89.5mm Wiesco piston is 265g with .945" compression height), etc. Wild cams would have a discussion of how stiff a valve spring is necessary. More valve lift would require a longer valve stem. It just seems that strength, valvetrain mass, etc. aren't Supra issues. But isn't that why we are talking about it 25 years later?

There are many ITBs for K-series and F-series Hondas. I haven't seen any for a 2JZ-GTE. But most of the aftermarket 2JZ-GTE are fabrications and it should be straightfoward to get one with a different runner length or even to make the runners interchangable so different runner lengths can be tested. It might be possible to get an approximation of Performance Trends Engine Analyzer Pro.

I'm guessing that once E85, race gas, or methnaol/water injection removed knock issues, it was easier to just increase the boost. As far as I can tell, the 2JZ-GTE never had a road racing history although the Supra MkIV did using other engines. That period ended over a decade ago.
 

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Pump design is just different.

I hear Goleby in Australia has turned up JZ engines to crazy RPM on wet sump pumps. I can't even begin to understand what he does different than the shops here.

He's over 9000rpm on a lot of the engines he builds. I thought it was 1JZ pumps that was the secret, but he does it on 2JZ pumps too.

Dry sumps for JZ engines are expensive.

A user here is using an accusump to help at high RPM. Looking forward to hearing about that, but he's not done building.
 

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There aren't many dry sump setups because of cost and because there isn't a dry sump solution that retains A/C. I agree that a dry sump would be awesome, and likely have HP gains and improved crankcase ventilation, but with so many other options for more HP, the not-overwhelming demand for higher rpm builds, and the loss of A/C, it hasn't been pursued very often except by serious road racers, etc.

There's a lot of discussion and thought about crankcase pressures in 2JZ's, for the most part the turbo oil drain tends to be -10AN and it's routed well into the upper oil pan so by the time crankcase pressure started preventing free oil drain, there'd be much bigger issues, such as the 2JZ's tendency to push out the FMS with lots of boost and insufficient crankcase ventilation. Most aftermarket setups go to a passive catch can and -10AN or -12AN lines to each valve cover. Inelegant but generally effective for most builds. I prefer closed PCV systems connected to a pre-turbo vacuum source.

Similarly, ITB's have been seldom explored on 2JZ's and most of them are NA builds. A short-runner intake manifold with suitable plenum volume and a big-enough single throttle body uncorks the limitations of the stock manifold at higher RPM and HP/boost levels and getting the best possible throttle response and boost thresholds aren't of as much concern as are consistent airflow and max HP. This is evidenced clearly with how most Supra builds are in their ideal element on a open stretch of highway, 1/2 mile event, or drag strip - not a road course.

Our thinking is very similar, and I'd love to build the hypothetical ideal 2JZ (ITB'd, high RPM, dry sump, etc) but my means are pretty limited for such an endeavor.
 

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I come from a place where lifter/bucket diameter, valve train mass and stiffness, and valve spring stiffness and life are the limiting factors. The goal was always to pop the valve off the seat and open as quickly as possible. On the intake, the closing was also fast. In oval racing there is no shifting, the cars come off the corner (in my class) in the mid- to hi- 4k rpm range depending on traffic/racing situations and top out at an intake limited just over 7k rpm.

The more aggressive the cam, the more power with smaller duration. The burden on the valve springs was huge. It is common to check the spring stiffness on the head regularly and replace the valve springs on an assembled engine in the car. Valve springs that are pushed get hot. Some come with coatings and surface finishes to reduce stresses and aid cooling. My SBC valve covers have valve spring oilers to cool the valve springs, tubes that spray oil on the valve springs, The cam lobes were from a design to push the limits of the Chevy .842 lifter; they had a more aggressive lobe for the Ford .875 lifter.

A Honda K20 and F20c have the same bore and stroke as a 2JZ. However, they have bigger valves and more lift, 11mm-12mm.

As a result, I'm having a bit of trouble understanding the limits on Supra cams. I'm confused by the low lift. With the very low valvetrain mass (no rocker at all and smallish valves). I would have expected more lift with the shorter durations since the low overlap of turbo cams and the lower compression of forced induction engines provides more latitude as the valve chases the piston down the hole on the intake stroke.

I would have hoped for a cam with specs like 224/228 @ .050 with 11mm of lift and an aggressive profile that banged the valve off the seat. The GSC S1/Kelford T/V202-C are nearly identical in specs 228/[email protected] with 9.9 cam lift, and it seems anything bigger makes for rough running. I'm guessing the lack of lobes that would seem more appropriate for road racing/oval racing is because this engine is used for mega-power, not mega-flexibility and mega-midrange coming off the corners.

Another question is why the Supertech sodium-cooled exhaust valve isn't widely used...or is it?

The rev limit is another question. The Honda S2000 F20c came from the factory with a 9k rev limit. K24s with rocker arms, a 99mm stroke and 55mm mains regular go 8k-9k and often 10k or more. The Supra has 62mm mains and shorter stroke and direct acting valve train...why are 8k numbers more common than 9k numbers. To get 1851 hp, Real Street rev'd to 9k. In that dyno pull/max power environment why not 10k?

The Supertech and Manley intake valves have undercut stems for increased flow at lower lifts. Based on my biases and what I've learned the +1 Supertech valves with the sodium cooled/Iconel exhaust, the softer GSC conical spring, and the GSC S1 seems a good combo a primarily street/pump gas engine. The Kelford T/V-202C cams would be identical.

A few hundred dollars one way or another is a rounding error this at performance level on this old a car. A lot of work goes into making the changes and there are lots of pieces that can break and be far more expensive to fix.

you seem quite knowledgeable and experienced, so for you and Jeff (Wreckless)...


re: cams - it is my understanding that the general trend is more lift/less duration for n/a motors and less lift/more duration for turbo motors. is this incorrect?

re: rev limit - it is my understanding that generally, most turbo motors are revved to just beyond where the turbo noses over (no longer holding power). for example, iirc, my rev limit was 9k-9200 with the 8685 that started to nose over around 86-8800.


craig
 
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