TPI VS TBI on a performance intake

[Supercharged111]

9.5:1 compression, with EFI, regardless of cam, will not build enough cylinder pressure to be a concern.

 

[Erik the Awful]

I am also concerned that the Valvetrain noise will tickle the knock sensors. I don't know if the Fast system uses knock sensors. If you see knock at hot idle from valvetrain noise you may be able to dampen their sensitivity.

When I went through school we were taught that you can cut a disc of notebook paper and put it between the knock sensor and block to dampen the sensitivity. The downside is it may not catch legitimate knocks.

 

[Supercharged111]

When I went through school we were taught that you can cut a disc of notebook paper and put it between the knock sensor and block to dampen the sensitivity. The downside is it may not catch legitimate knocks.

Or you can shore it up in the tune.

 

[kenh]

You WILL have coolant in the oil if the bolts aren't sealed.
There are mistakes on the Summit website. What is the part number for the bolts you purchased?

Right or wrong this is what I used to seal my bolts. Bought a larger tube though

https://shop.advanceautoparts.com/p/permatex-high-temperature-thread-sealant-169-oz-59235/16160026-p

IIRC some of my intake bolts also penetrated the water jacket.

Ken

 

[LC2NLS6]

No such thing as a torque monster, just means it has no power and only thing left is some torque before it falls on its face. You need big displacement or more engine speed. Pick one. Put all the money in the best heads and tune you can, which means iron vortecs with upgrades, and a converter that flashes over 2000.

 

[L31MaxExpress]

Spent a morning talking with Ken here: https://firstfuelinjection.com/ the day after I posted this here.

The man KNOWS TPI...Build TPI systems and he said a Stock system will work great on my engine up to 5000RPMs as I am NOT building a hot rod, BUT if I was he has systems that can feed a monster to over 6000 and give great torque and power.

Also the reason everyone thinks the the TPI Peeks at 2800RPMs is because that is the Torque peek of the CAMSHAFT....

So I getting down to the wire, the only remaining question is the PCM...

Rich

TPI peaks where TPI peaks because of resonance wave tuning and the RPM where that wave positively effects Volumetric Efficiency is dictated by total runner length alone. That same wave actually fight VE at other RPM points. You can change the cam to rotate the ends of the torque curve up or down but the peak will still end up in the 2,800-3,200 rpm range where the resonance wave is the strongest. Smaller cam will deliver a little more low-end torque at the expense of hp and a larger cam will deliver a little more top-end power at the expense of low-end torque. The wide LSA is shooting yourself in the foot for low-end torque by closing the intake valve later. 110 or even 106 LSA would produce drastically more low-end torque. Probably in the neighborhood of 30 ft/lbs more at 1,500-3,000 rpm range.

 

[Supercharged111]

TPI peaks where TPI peaks because of resonance wave tuning and the RPM where that wave positively effects Volumetric Efficiency is dictated by total runner length alone. That same wave actually fight VE at other RPM points. You can change the cam to rotate the ends of the torque curve up or down but the peak will still end up in the 2,800-3,200 rpm range where the resonance wave is the strongest. Smaller cam will deliver a little more low-end torque at the expense of hp and a larger cam will deliver a little more top-end power at the expense of low-end torque. The wide LSA is shooting yourself in the foot for low-end torque by closing the intake valve later. 110 or even 106 LSA would produce drastically more low-end torque. Probably in the neighborhood of 30 ft/lbs more at 1,500-3,000 rpm range.

I agree with everything in this post. With this logic I'm lost on why you feel the LT1 car cam gives up nothing to the truck and/or Ramjet cam.

 

[L31MaxExpress]

I agree with everything in this post. With this logic I'm lost on why you feel the LT1 car cam gives up nothing to the truck and/or Ramjet cam.

Because the truck or marine cam is so small you have to pull a crap load of timing to keep it from detonating on 91. There is a certain point where cams are too small too. Both the vortec truck cam and the marine cam are too small. The LT1 aluminum head or LT4 cam is about the perfect cam duration that it does not trade off anything over the converter stall speed. LT4 cam, 1.6 rockers and a 2,800 converter knocked a full second off the 0-60 of my Express van and it pulled hills every bit as well in overdrive with the converter locked up. 70 mph at 2,000 rpm it lost nothing to the stock cam.

 

[Supercharged111]

Because the truck or marine cam is so small you have to pull a crap load of timing to keep it from detonating on 91. There is a certain point where cams are too small too. Both the vortec truck cam and the marine cam are too small. The LT1 aluminum head or LT4 cam is about the perfect cam duration that it does not trade off anything over the converter stall speed.

I've heard of this on big blocks, especially ones with crappy heads. That said, the truck cams (when mistakenly installed in an LT1 car motor) make more torque than the car cams to the tune of around 20 ft/lb. I noticed the black box didn't tolerate much timing, but with the 411 it gobbled it up. Have you made this observation on the 411?

 

[L31MaxExpress]

I've heard of this on big blocks, especially ones with crappy heads. That said, the truck cams (when mistakenly installed in an LT1 car motor) make more torque than the car cams to the tune of around 20 ft/lb. I noticed the black box didn't tolerate much timing, but with the 411 it gobbled it up. Have you made this observation on the 411?

For me it was the opposite. Black box liked timing and no knock counts to speak of. 0411 had places it was pulling 10° retard with the stock timing table. Remember the Vortec heads flow better than the aluminum heads. Post the dyno sheet of your F-car. I can post one of the 395 cam in a L31 with a marine intake. LT1 cam has a broader power curve than the L31 marine cam by far. Granted I had tri-y headers and was pushing power through a 4L85E/9.5" 14-bolt while turning a mechanical engine fan. Your LT1 murdered my L31 marine setup. Was not until I put E85 in it that I was able to get some timing in the lower rpm ranges. I made 230 hp and 304 tq with the marine cam and weak valve springs. 257 hp and 310 tq after swapping the springs. E85 pushed it to 272 hp and 330 tq. On E85 it liked 32° total advance from 2,400+, no less, no more. 2° either way anywhere in the curve killed 10-15 ft/lbs. On 91 it detonated at anything more than 24° below 3,200 and I had to limit to 29° total with advance peaking at 4,800.