TVIS & Bigger Cams

Alex170984
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TVIS & Bigger Cams

Postby Alex170984 » Wed Feb 10, 2016 1:40 am

Hi all,

I am currently running some Cat Cams 252/260 with 8.5/9.0 lift on the standard ECU. Idle when up to temperature is okay at around 1k rpm, no issues with that.

The engine is from a Corolla originally with 9:4:1 compression, but upped it to about 10:21.

Issue I am having, which is probably down to the camshafts is that my torque at the lower end of the scale is poor.

I have also read that removing the TVIS can improve low end torque with bigger than standard cams, is this true?

Thanks in advance and all advice is greatly appreciated

Alex

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Re: TVIS & Bigger Cams

Postby totta crolla » Wed Feb 10, 2016 1:53 am

Easy to try it out. Just disconnect the vacuum hose.
http://websworld.org/marcel/tech/tvis/tvis.html

My guess is that it will be better with TVIS

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Re: TVIS & Bigger Cams

Postby davew7 » Wed Feb 10, 2016 5:03 am

I'm running almost the same set-up with the stock ECU. Slightly less lift, CR, and no TVIS. Try advancing the intake 3*. If you are willing to break into the engine, a thinner head gasket would also help. Dave W

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Re: TVIS & Bigger Cams

Postby yoshimitsuspeed » Wed Feb 10, 2016 8:36 am

The TVIS should always be a benefit to low end. The only reason to remove it is when the whole intake becomes such a restriction to top end performance that it's worth sacrificing the low end losses for much more top end with a completely different manifold setup or ITBs.

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Re: TVIS & Bigger Cams

Postby SgtRauksauff » Wed Feb 10, 2016 8:37 am

I'm running a 7-rib largeport, with first oversize (0.5mm, .020") 10.3:1CR pistons (storm GSi spec) TODA 264°int/256°exh (don't remember the lift, either 7.9 or 8.5, but it's NOT the 9.0), stock ECU, and 8mm TRD headgasket. If the head comes off, I'll put on a 6mm for that much more fun.

Running the TVIS gave much more noticeable differences with the stock cams (intake noises are beautiful), and I still have TVIS running with the TODA cams.

These engines aren't torquey at all, I got 108hp/98lb-ft on the stock cams.
after install of the TODA cams, (and FPR,and 4-1 header) i got 133.0/105-ish.

Alex170984
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Re: TVIS & Bigger Cams

Postby Alex170984 » Wed Feb 10, 2016 9:01 am

davew7 wrote:I'm running almost the same set-up with the stock ECU. Slightly less lift, CR, and no TVIS. Try advancing the intake 3*. If you are willing to break into the engine, a thinner head gasket would also help. Dave W


Hi,

I'm running a .8mm metal head gasket anyway.

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Re: TVIS & Bigger Cams

Postby Alex170984 » Wed Feb 10, 2016 9:02 am

yoshimitsuspeed wrote:The TVIS should always be a benefit to low end. The only reason to remove it is when the whole intake becomes such a restriction to top end performance that it's worth sacrificing the low end losses for much more top end with a completely different manifold setup or ITBs.


I've just got sod all low end.

May put the old cams back in to see if it's a cam issue.

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Re: TVIS & Bigger Cams

Postby yoshimitsuspeed » Wed Feb 10, 2016 9:07 am

As suggested you might try playing with the cam timing. Those are tiny cams so with your small compression bump the low end should feel similar to stock.

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Re: TVIS & Bigger Cams

Postby oldeskewltoy » Wed Feb 10, 2016 10:13 am

yoshimitsuspeed wrote:As suggested you might try playing with the cam timing. Those are tiny cams so with your small compression bump the low end should feel similar to stock.


this......... although the intake cam duration is a bit more then "tiny" at 230 degrees duration @ .050"(1.2mm) this cam is closer to a 272, then a 264.... so a bit more compression likely would've helped

keep the TVIS

http://club4ag.com/tech-data/camshaft-story-revised/ wrote:Using adjustable cam sprockets can optimize the performance of any cam. This allows for “degreeing” in the proper cam timing for the particular engine and intended use. This procedure is best carried out on a dynamometer so that quantifiable results can be measured. The advancing or retardation of cam timing will affect the peak power of the engine by moving the power band up or down the curve. There are many adjustable cam sprockets to choose from, each differing in design from all aluminum to using steel (less thermal expansion), but the most convenient to use are the ones with precision markings to allow for track turning and returning to the original settings. In general, advancing both camshafts increases bottom-end power and retarding both cams will increase top-end by giving higher peak RPM power. On twin-cam engines, changing the lobe center separation between exhaust and intake will change the valve overlap. This can be used to improve top-end or bottom-end, but this depends on the critical placement of the intake closing and exhaust opening events. The placement of both events has a significant effect on power, i.e., exhaust valve opening determines the beginning of the exhaust cycle and cylinder blow down, and the placement of the intake closing event fixes the balance between cylinder filling and intake reversion. It must be emphasized that this is only a generalization and that you must perform dyno/track testing to fully realize the benefits. In the absence of a dyno, timed acceleration tests can be performed. These acceleration tests can also be performed using a precision accelerometer. Tuning the cam to the specific engine operations, i.e., acceleration from a stop, between two RPM ranges, etc. will maximize what is important to you. Peak horsepower is only impressive on a dyno. By its self, it will not improve track times. Note, when adjusting the cam sprocket, make sure the ignition timing is corrected between each cam adjustment. The exhaust cam drives the distributor and any change to the exhaust cam will change the ignition timing. After changing the cam timing and correcting the ignition timing, the fuel calibration must also be checked. Cam timing has a profound effect on the air/fuel mixture and if not optimized for each cam timing setting you will not know if the effect of the change in cam timing is positive or negative.


here is your cam timing card........ http://www.catcams.com/products/camshaf ... TUP_id=828


To the OP.... do both cams have distributor drive gears machined into them?? You might swap the intake cam, and exhaust cam and see if you prefer them that way.... don't forget to make sure the valve clearances are checked
OST Cyl head porting, - viewtopic.php?f=22&t=300

Building a great engine takes knowing the end... before you begin :ugeek:

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Re: TVIS & Bigger Cams

Postby SgtRauksauff » Wed Feb 10, 2016 2:53 pm

my TODA cams ended up giving the absolute best performance at 0° adjustment, for both of them. what I DID end up adjusting, was 4°ignition advance, and 4psi of fuel pressure.

What Oldeskewl said regarding the valve clearances.. I think it's very important. When I did mine, all the intake were identical, and all the exhaust were identical. to .001. Since these engines are so small, small lacks of efficiency really add up quickly. But making the engine as close to perfect as you can has real benefits as well. yeah, 133hp isn't that much compared to a lot of my friends, but a jump from 108 to 133 with just cams, header, fpr? that's 24% inprovement, which is a HUGE number relatively.

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Re: TVIS & Bigger Cams

Postby Erik_drift10 » Mon Feb 22, 2016 1:18 pm

SgtRauksauff wrote:I'm running a 7-rib largeport, with first oversize (0.5mm, .020") 10.3:1CR pistons (storm GSi spec) TODA 264°int/256°exh (don't remember the lift, either 7.9 or 8.5, but it's NOT the 9.0), stock ECU, and 8mm TRD headgasket. If the head comes off, I'll put on a 6mm for that much more fun.

Running the TVIS gave much more noticeable differences with the stock cams (intake noises are beautiful), and I still have TVIS running with the TODA cams.

These engines aren't torquey at all, I got 108hp/98lb-ft on the stock cams.
after install of the TODA cams, (and FPR,and 4-1 header) i got 133.0/105-ish.



I've been looking at different builds for a 7rib and I'm liking your build. How much was it with the toda cams, pistons and trd headgasket? Oh and what does FPR stand for?
I have a spare 7rib sitting around that I want to build. Nothing too crazy hence why I like your build. Thanks

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Re: TVIS & Bigger Cams

Postby yoshimitsuspeed » Mon Feb 22, 2016 8:00 pm

Erik_drift10 wrote:

I've been looking at different builds for a 7rib and I'm liking your build. How much was it with the toda cams, pistons and trd headgasket? Oh and what does FPR stand for?
I have a spare 7rib sitting around that I want to build. Nothing too crazy hence why I like your build. Thanks


Toda cams are nice but very expensive. IMO your money can be better spent elsewhere.

I assume you are trying to stay on the stock ECU?
What octane do you plan on running? When you say you don't want to do anything crazy what do you mean? Are you just trying to stay on the stock ECU? Are you looking for a build that doesn't require much effort on your part to monitor and fine tune it or do you have other reasons?

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Re: TVIS & Bigger Cams

Postby Alex170984 » Wed Feb 24, 2016 6:32 am

oldeskewltoy wrote:
yoshimitsuspeed wrote:As suggested you might try playing with the cam timing. Those are tiny cams so with your small compression bump the low end should feel similar to stock.


this......... although the intake cam duration is a bit more then "tiny" at 230 degrees duration @ .050"(1.2mm) this cam is closer to a 272, then a 264.... so a bit more compression likely would've helped

keep the TVIS

http://club4ag.com/tech-data/camshaft-story-revised/ wrote:Using adjustable cam sprockets can optimize the performance of any cam. This allows for “degreeing” in the proper cam timing for the particular engine and intended use. This procedure is best carried out on a dynamometer so that quantifiable results can be measured. The advancing or retardation of cam timing will affect the peak power of the engine by moving the power band up or down the curve. There are many adjustable cam sprockets to choose from, each differing in design from all aluminum to using steel (less thermal expansion), but the most convenient to use are the ones with precision markings to allow for track turning and returning to the original settings. In general, advancing both camshafts increases bottom-end power and retarding both cams will increase top-end by giving higher peak RPM power. On twin-cam engines, changing the lobe center separation between exhaust and intake will change the valve overlap. This can be used to improve top-end or bottom-end, but this depends on the critical placement of the intake closing and exhaust opening events. The placement of both events has a significant effect on power, i.e., exhaust valve opening determines the beginning of the exhaust cycle and cylinder blow down, and the placement of the intake closing event fixes the balance between cylinder filling and intake reversion. It must be emphasized that this is only a generalization and that you must perform dyno/track testing to fully realize the benefits. In the absence of a dyno, timed acceleration tests can be performed. These acceleration tests can also be performed using a precision accelerometer. Tuning the cam to the specific engine operations, i.e., acceleration from a stop, between two RPM ranges, etc. will maximize what is important to you. Peak horsepower is only impressive on a dyno. By its self, it will not improve track times. Note, when adjusting the cam sprocket, make sure the ignition timing is corrected between each cam adjustment. The exhaust cam drives the distributor and any change to the exhaust cam will change the ignition timing. After changing the cam timing and correcting the ignition timing, the fuel calibration must also be checked. Cam timing has a profound effect on the air/fuel mixture and if not optimized for each cam timing setting you will not know if the effect of the change in cam timing is positive or negative.


here is your cam timing card........ http://www.catcams.com/products/camshaf ... TUP_id=828


To the OP.... do both cams have distributor drive gears machined into them?? You might swap the intake cam, and exhaust cam and see if you prefer them that way.... don't forget to make sure the valve clearances are checked


The dizzy gear is only on the exhaust cam, so cannot swap em over unfortunately.

However I may see if anyone has any 256/264 HKS cams kicking around and sell mine.

Valve clearances are all okay. These were done when my head was rebuilt

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Re: TVIS & Bigger Cams

Postby SgtRauksauff » Wed Feb 24, 2016 9:00 am

Erik_drift10 wrote:
SgtRauksauff wrote:I'm running a 7-rib largeport, with first oversize (0.5mm, .020") 10.3:1CR pistons (storm GSi spec) TODA 264°int/256°exh (don't remember the lift, either 7.9 or 8.5, but it's NOT the 9.0), stock ECU, and 8mm TRD headgasket. If the head comes off, I'll put on a 6mm for that much more fun.

Running the TVIS gave much more noticeable differences with the stock cams (intake noises are beautiful), and I still have TVIS running with the TODA cams.

These engines aren't torquey at all, I got 108hp/98lb-ft on the stock cams.
after install of the TODA cams, (and FPR,and 4-1 header) i got 133.0/105-ish.



I've been looking at different builds for a 7rib and I'm liking your build. How much was it with the toda cams, pistons and trd headgasket? Oh and what does FPR stand for?
I have a spare 7rib sitting around that I want to build. Nothing too crazy hence why I like your build. Thanks


yoshimitsuspeed wrote:
Erik_drift10 wrote:I've been looking at different builds for a 7rib and I'm liking your build. How much was it with the toda cams, pistons and trd headgasket? Oh and what does FPR stand for?
I have a spare 7rib sitting around that I want to build. Nothing too crazy hence why I like your build. Thanks


Toda cams are nice but very expensive. IMO your money can be better spent elsewhere.

I assume you are trying to stay on the stock ECU?
What octane do you plan on running? When you say you don't want to do anything crazy what do you mean? Are you just trying to stay on the stock ECU? Are you looking for a build that doesn't require much effort on your part to monitor and fine tune it or do you have other reasons?


FPR = Fuel Pressure Regulator I used a SARD model.
I'm pretty sure the TODA cams were ~900 for the pair, including shipping from JP. Yoshimitsuspeed is right, they're kind of ridiculously priced these days. I like them, but I don't know if I would recommend them, since several other manufacturers have similar offerings these days.

I think the pistons were around 200 for the set; I got them through an acquaintance who worked at a GM dealership and was able to get them at cost.

And I don't remember the price on the head gasket, I think I purchased it from a dealership in California who had a sales rep who was friendly with a couple of the forums; it's my understanding that she moved on in her career, and is no longer a contact for us.

I think a huge part of the success of my build was not just due to the parts, but in the preparation. Extra-meticulous with the valve shims, and I cleaned up the heads with 80-grit on the intake side, and worked up to 320 on the exhaust. I didn't do any bowl or radius work like Dan does, and I don't think I even touched the 'joggles' in the combustion chamber. Hand-filed and beveled the rings and made sure the gaps were exactly as specified in the manual, I had the machine shop balance the rods/pistons/pins for me and double-checked when they came back.

--sarge

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Re: TVIS & Bigger Cams

Postby yoshimitsuspeed » Wed Feb 24, 2016 7:13 pm

Alex170984 wrote:
However I may see if anyone has any 256/264 HKS cams kicking around and sell mine.

Valve clearances are all okay. These were done when my head was rebuilt


If you are interested in buying new I should be able to get you into something that would put a bigger smile on your face than those HKS.

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Re: TVIS & Bigger Cams

Postby Alex170984 » Thu Feb 25, 2016 4:00 am

Thanks for the offer but I'm getting married in 6 months and I cannot afford to buy new things at the moment.

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Re: TVIS & Bigger Cams

Postby jinx » Thu Feb 25, 2016 4:58 am

At the moment ? .......by august you won't be able to buy any new stuff at all - lol

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Re: TVIS & Bigger Cams

Postby yoshimitsuspeed » Thu Feb 25, 2016 7:47 pm

Haha well considering the hKs used to go for almost as much per cam as mine do for a set and considering they are getting rare I wouldn't be surprised if they cost you almost as much as mine or Tomei or something new. Jiinx is probably right though haha.

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Re: TVIS & Bigger Cams

Postby d3nso » Fri Feb 26, 2016 12:30 am

Why ditching the catcams? As Dan said the cams provide similar or even better perfirmance than the HKS ones. Try to play with the timing some more.

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Re: TVIS & Bigger Cams

Postby Alex170984 » Mon Feb 29, 2016 8:57 am

Is there a way of jamming the TVIS butterflies open by not disassembling the whole rail?

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Re: TVIS & Bigger Cams

Postby totta crolla » Mon Feb 29, 2016 10:52 am

Alex170984 wrote:Is there a way of jamming the TVIS butterflies open by not disassembling the whole rail?


You ignored my post above advising you to not only try disabling the TVIS but also how to do it.... :roll:

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Re: TVIS & Bigger Cams

Postby Alex170984 » Tue Mar 01, 2016 1:30 am

Sorry didn't read it properly, apologies.