mad_308

Does any one now what a TPI Inlet system flows hp wise? It will be on a duel fuel 350 with mildly ported 186 fuellies, 302 duration .488" lift stick, 10 to 1 comp. To be fitted to my cruiser to replace the low comp gen2 dog thats in there at the moment. I also have some 10.5 to 1 lumpy tops but i am undecided. Any advise would be appreciated.

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MAD_308
Slave to the mighty 308!

k383

mad.............i looked into the tpi set up for my 383 (516hp)
and after much research i decided that it was not going to be anywhere near what i needed. even with pumps and mods if i remember right it could only support around 400hp. maxed out!!
with big cams i dont think they can get enough air in and there are limits to injector sizes. (sorry i cant remember exact details)

so i went for
8, 45ml throttle bodies on moon quad webber manifold, with bosch injectors and 040 motorsport pump.......with motec ecu.....should support upto 700hp

i guess it would depend on you engine combo, and the work it will do.

for me......i want to get my front wheels off the ground at the strip!!!!!
lol

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guilty bystander........ dontlethemdoit

mad_308

Thanks for that! 400hp will be should be ok as i want a fat torque curve with plenty around 2500rpm to 5000rpm. The Landcruiser is a heavy bitch and the only time i need the front runners of the deck is when launching of errosion humps or sand dunes, definitly need them on the ground when towing my rally car. If they are anything like the bunch of bananas on 304's they probably wont flow muh past 5500rpm. Also thinking of plumbing an LPG vapour injection system into the runners to get the most out of it.

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MAD_308
Slave to the mighty 308!

vetteoz

The long runners on a TPI give you just that; shit loads of torque if you can put it to use.Pulls from off idle.
Remember the stock TPI was 245Hp / 330ft/lb with a pissy .413 /. 428 cam.
The similar spec , later LT1 with short runner intake made 300Hp but only 310 ft/lb.
The TPI in virtually any form will peak at 4500.
I have big TB , ported plenum , big tube runners and siamized base.Always traps best ET shifting at 4500 , will rev higher but ET slower.
302 adv is probably more duration than a TPI can use.Will lose power down low from overlap and not see enough revs to use it.
Most of the aftermarket TPI cams are
210-220 @50 dur ;
.480 - .510 lift.

mad_308

Thats helpfull info Ta! The cam specs actually are 224 in @50 and 234 ex @50 dur .465" inlet valve lift total and .488" total ex valve lift with 1.5 rockers. Do you think this cam is still to big for the TPI? What size is the standard TB and what size is yours? Remembering that my engine only a 350+ .040" I was hoping it would at least see 5000rpm. Do you know what hp your 383 combo has?

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MAD_308
Slave to the mighty 308!

vetteoz

The reference above was on my 350.
With 208/221 .470 /.510 cam about 320Hp but well over 400ft /lbs. Killed LS1's for first 60 feet w/ 3.07 gears.

Most of the popular TPI cams are less than 225 dur but lots of lift.Your cam specs are more common to a short runner LT1 and at those durations, a higher stall is recommended.
Stock TB is 48mm , more than adequate.

This is a comparison on a 383 but the intake differences are relative.
Articles That Use Comp Cams® Products
Note all the TPI setups flatline over 4500 but arwesome torque down low.If you can get that to the ground you don't need the big revs.

FYI , on my 383, the modded TPI pulled 1.70 in the 60 , the HSR does 1.76 but runs 1/2 sec faster because of more top end.

mad_308

Thats an excellent informative article! Thanks vetteoz! I will source the tpi then a more suitable cam grind . Sounds perfect for my intended use.

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MAD_308
Slave to the mighty 308!

vetteoz

Excellent "how to swap TPI" site

Since its inception in 1985

introduction page

Troubleshooting / wiring / ECM . etc