Pontiac - Boost Turbo, supercharged, Nitrous, EFI & other Power Adders discussed here.

          
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  #21  
Old 11-29-2021, 11:32 AM
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Agree. Never understood that 700 hp number. Must be an NA Number.

Luhn Performance 860+ Hp 5300 rpm. 160 HP more than the quoted The engine will
scatter, HP point.

Tom V.

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  #22  
Old 11-29-2021, 10:05 PM
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FWIW: I feel there is things you can do to help the block. I feel the stock side mounts and that much power even if they are strapped, can cause block flex. With out a real long winded post, once I put a mid plate on my car, I do not see cap walk. same everything in the motor. I also have the car lifting dead straight on launch with a drag bar. This is my opinion, from my personal experience.

  #23  
Old 11-29-2021, 10:53 PM
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Quote:
Originally Posted by JSPONT View Post
FWIW: I feel there is things you can do to help the block. I feel the stock side mounts and that much power even if they are strapped, can cause block flex. With out a real long winded post, once I put a mid plate on my car, I do not see cap walk. same everything in the motor. I also have the car lifting dead straight on launch with a drag bar. This is my opinion, from my personal experience.
TRUTH

Which is why some use a chain and turnbuckle on the left FRONT of the block, or just a strap with a SLIGHT clearance slot in the strap.

There are times when a midplate cannot be packaged with all of the other
items the owner wants to keep. Ok for a race car/TOY. Not so good for a daily driver (but even a daily driver can rip apart the drivers side mount).

Tom V.

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  #24  
Old 11-30-2021, 02:07 AM
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At that power level, why not get an aftermarket block as cheap insurance?
At 1200hp, how many of those parts are gonna survive a moderate to serious issue?

I'd build the aftermarket to 1200+ and use the current block as the 700hp place holder when the big boy goes down. (I'm assuming you're gonna need builders who are 6-12 months out on builds these days).

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  #25  
Old 12-02-2021, 07:11 AM
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Quote:
Originally Posted by turbo69bird View Post
If it’s put together correctly there’s no reason it wouldn’t

The biggest killer of an engine is going to be detonation from a poorly tuned engine , properly / safely tuned for a turbo engine would be a very fat and lazy tune for a naturally aspirated engine.

When I’m
Under full boost I want 10-1 afr. I know I’m safe if there’s any fluctuation or mistakes. It’s a very conservative tune but it keeps it alive . It leaves a little power on the table but your gonna keep it together .
Hey Jeff I bought my turbo S475 from you over 6 years ago , finally getting to drive the car and do some tuning , can you tell me what your timing is set as ? Locked out or are you pulling timing as it makes boost ? Thanks bud

  #26  
Old 12-21-2021, 11:15 AM
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That 700 horsepower threshold for a production block had always been a bit of a headscratcher for me as well. The question I would always have is "How are you getting to that level? Was it a NA stroker with a 4.5-inch arm and spinning to 7,500 rpm with 13:1 compression and an .800-inch lift cam? That's going to be a very problematic combo for a stock block. Failed cylinder walls, lifter bores, the chance of splitting the whole thing is very present.

Another problem combo is an overdriven 6-71 or 8-71 combo. Blowers will put enormous stress on the end of the crank and in turn will encourage block flexing. It's not a huge problem for a mild, low-boost street combo but things get very questionable as the rpms and boost go up.

A far friendlier setup would be a turbocharged short-stroke setup using a max of 3.75 inches. A combination like that will not put nearly as much stress on the block for a few reasons. One, the stroke will keep the stress on the cylinder walls down and will be less prone to cracking down the middle. There is also nothing on the end of the crank to cause stress and the cam can be relatively mild, so the lifter bores are not under the stress caused by a radical profile.

I have been a fan of turbos since I saw an 1800 cc VW make 460 horsepower in 1979 and lay down nine-second runs. Look up "Little Leroy." Then in 1996, I saw Marty Palbykin take everything I ever believed about turbos and make it come to life in Norwalk. He made 1,600 horsepower with a stock 1967 400 block without filling or block bracing, street-ported 670 heads and a 400 RAV crank. I will never forget that.

If you're looking for a street/strip stock block combo that would live, I would look to the 350. The smaller bore helps with block sealing, they tend to be a little beefier where it's needed and valve shrouding isn't an issue when under boost. Remember, Mopar went to a smaller bore for their supercharged Hemis. And GM didn't use the 427 LS7 as the basis for their supercharged engines. They stuck with the 6.2's smaller bore size for sealing and thicker cylinder walls.

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  #27  
Old 12-21-2021, 12:01 PM
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Excellent post DON. When you figure that 5.4L type engines with average turbos can make 1400 hp with proper tuning and modern electronics, a smaller engine is a good way to go. And with Turbos very common to be running 25-30 psi of boost to make that HP with the smaller engine.

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  #28  
Old 12-21-2021, 01:01 PM
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IMO..........its like going on road trip in your car with BALD TIRE............you may make your destination or you may not!


GTO George

  #29  
Old 12-21-2021, 07:04 PM
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The mention of a 350 for a turbo application has always been my thought.

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  #30  
Old 12-21-2021, 08:39 PM
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Charlie66 can destroy the tires on his 64 Pontiac 4 cflinder (many videos out there)
with his 206 cid 4 cylinder Turbo engine 800 HP 4 HP per cid. 34 psi of boost pressure.

500 cid engine is 2.5 times bigger and the charlie66 engine would be 2000 hp if scaled against a engine of that size.

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  #31  
Old 12-22-2021, 03:25 PM
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Ive talked to Charlie (at the Pontiac race a couple of times) and if I recall he has never Dynoed his engine. He's doing great at those boost levels with that 4 banger! Im thinking i could make over 2,300 hp maybe more at that boost level. "The Question/Thread" was will a "stock block" hold up at 1,200 HP not at 1,400, 1,500 0r 2,000 HP.........if he doesn't race it all the time "special" not 1/4 mile passes! At the Pontiac race this year i made 13 quarter mile pass in 3 days a factory block wouldn't hold up to that much abuse, thats why race cars run aftermarket blocks. So if he just cruises it and jumps on it once in a while keeping the rpm down he could be good BUT I wouldn't.....thats just me!


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  #32  
Old 12-25-2021, 09:06 PM
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If it is a street car, with trips to the track it will hold up for years if the tune and chassis is right. To be honest. 1200 hp on the street with a small tire car is a waste. it gets real tricky after 750 on the street. You can never leave on a psi on the street like on a prepped track. On the street with my 461 I leave on 5-6 psi and at 11-12 on the top end and still can come loose in 3rd gear. I put about 30 passes on it this year and 3000 street miles. Just about the same for the last 5 years with no issues. I have had friends blow up better built engines than mine with less power. Greedy tunes and lack of reading plugs will get ya. If you can swing the a/market block go for it. They are no picnic. A ton of machining and then oil pans never fit amount other issues. JMO

  #33  
Old 12-25-2021, 11:23 PM
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Quote:
Originally Posted by GTOGEORGE View Post
Ive talked to Charlie (at the Pontiac race a couple of times) and if I recall he has never Dynoed his engine. He's doing great at those boost levels with that 4 banger! Im thinking i could make over 2,300 hp maybe more at that boost level. "The Question/Thread" was will a "stock block" hold up at 1,200 HP not at 1,400, 1,500 0r 2,000 HP.........if he doesn't race it all the time "special" not 1/4 mile passes! At the Pontiac race this year i made 13 quarter mile pass in 3 days a factory block wouldn't hold up to that much abuse, thats why race cars run aftermarket blocks. So if he just cruises it and jumps on it once in a while keeping the rpm down he could be good BUT I wouldn't.....thats just me!


GTO George
Spoke with Charlie and he said that is not true what you posted in Post #31.

His car has been on a chassis dyno at least once if not more times.
Do not believe he has been on a engine dyno though (so your post may be 'somewhat' correct).

He has actually been at those boost levels many times and you are assuming given power levels vs actually being at those power levels.

I spoke with him about your post, right after you made your post.
Words right out of his mouth on the phone.

Tom V.

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Last edited by Tom Vaught; 12-26-2021 at 12:09 AM.
  #34  
Old 12-27-2021, 01:33 PM
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LOL.............OK!



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  #35  
Old 01-01-2022, 12:43 AM
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So recap -

* 700HP limit is NOT an accurate statement... (I always believed it had more to do with rotational weight and mean piston speed ratios)
* Short Stroke + Boost + Proper tune = Well over 700HP capability
* Charlie with his 206 cid 4 cylinder Turbo engine making 800 HP has in fact been on a DYNO.

Its a shame the P350 has been shunned to the point it is considered better used as boat anchor than a high performance engine. It would be awesome to see someone build one to handle 25+lbs of boost.... Wallace racing calculator suggest that if you build a P350 that makes 350HP and add 25lbs of boost... you would be making 945HP... 30lbs boost raises it over 1,068HP... Sounds like a fun project to me...

SPEED SAFE, NICK

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  #36  
Old 01-01-2022, 11:50 AM
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5.4l liter engine is 330 cid.
4.6L engine is 281 cid.

350 - 351 engine is 5.8L

Facts: 281 cid engine has run 5.70s in the quarter with good heads and lots of boost
70 psi. 5.4L engine has made 1400 hp on the dyno with good heads.

351 engines with simple belt driven superchargers have made about 1000 hp and
have since the mid 1990s.

It has to do with the block strength and the other related rotating/reciprocating parts.
With good parts, no reason why your post would not be totally possible and a fun project.

If Charlie66 can make 800 on 206 cid, a good 300 cid engine could and has made over 1000 hp for many years.
Big cid engines are there for durability over the long haul.
That is why Pontiac engines, 389, 400, 421, 428, 455 were excellent high mileage
capable passenger car engines for many years. And most small Pontiac engines are
at least 326 cid or larger. So agree AIR RAM.

Tom V.

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  #37  
Old 01-01-2022, 04:53 PM
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Funny…….lol!



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  #38  
Old 01-01-2022, 05:49 PM
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Think you have it covered Air Ram.

Happy New Year.

Tom V.

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  #39  
Old 01-02-2022, 06:20 PM
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Quote:
Originally Posted by Pontiaco View Post
Got a 70 455 stroke to 496 eagle forged Bottom assembly balanced, Milondon 4bolt caps , Kauffman high ports 80cc ,solid roller on a 68 firebird.

Got twins gt45s turbos, question is would the motor stay together to 1200hp??

Th400 w/3.25 9in
So back to the TOPIC!
It will live But it all depends on how much you BEAT it up. Boost is very addictive and its so EASY to turn it up. I don't know how much HP i was making in my stock block with 4 bolt main before I broke it.....i was running 9.1's and racing basically every weekend. Nowhere near 1,200 HP (may around 850 HP) , I only shifted at around 5,200 RPM BUT if you get stupid with it it will break and you will be spending more money on a rotating assemble. Thats why racers buy an aftermarket block.....its cheaper in the long run! Oh by the way im not sure how long that turbo 400 will last, mine use to beak every year until I stepped to a Rossler TH210 Trans. of course i am making more HP then 1,200 with my KRE low boost engine. Anyways its just my opinion on my experience racing with boost. Thanks and have a great year!


GTO George

  #40  
Old 01-02-2022, 07:40 PM
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PUT THE HIGHEST AMOUNT OF MONEY YOU CAN AFFORD, AS WAS MENTIONED, INTO BUYING QUALITY PARTS THAT WILL ALLOW THE ENGINE TO SURVIVE OVER TIME.

This means a good quality set of heads, but more importantly the parts inside the block:
Connecting Rods, Pistons, Crankshaft, Oil System, and Valvetrain.

In Charlie66's Engine, I helped him get a custom Billet Moldex 4 cylinder crankshaft, a set of custom Carrillo Connecting Rods, and proper Pistons designed for high boost pressures. The engine has been very durable to date (highest boost pressure has been in the 44 psi range).

Rusty4 Cylinder also had a Moldex 4 cylinder crankshaft made and in each case the process took close to a year before the crank was received but was "spot-on" for the dimensions as expected. Some others like Bryant crankshafts may be quicker but not any higher quality than Joe Flowers, (the Moldex Owner) produces. Good parts are not cheap.

Tom V.

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