Motor Guru Please teach me
Le Mans Master
Joined: Jun 2006
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From: One day you're a Comet...the next day you're dust... Arkansas
I'm not saying that at all, but to reach a 350 CHP on a L98 is takes a several expensive mods to the engine. You can't just put a mild cam, headers , and do intake porting. Go back and read my post about what it takes to hit 350 HP.
Last edited by BADDUCK; May 31, 2010 at 06:15 PM.
Race Director
Joined: Jun 2009
Posts: 10,428
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From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
This is not a negotiation, I was trying to give the OP a realistic opinion based of his stock 350 engine. The mild mods you claim will exceed the CHP of the LT4 cars are just way too optimistic. As you admit you have no experience with TPI replacement intakes. GM engineers really couldn't improve horsepower too much in the C4 without going to short runner intakes like the LT intakes. The basic reason your estimates are badly flawed is the TPI intake. You can port the hell out of it and still not get much improvement. Remember, the TPI was developed for the 305 engine. 300 CHP would be about the limit for what you suggest.
and this
indicate (to most anyway) humor. Since that didnt work out so well let me try this approach.. for 2500 bucks he aint gonna buy an intake and heads.. you think 300 chp is all it will make fine (hell 270 would be 30 more than he has now and its not the point, making torque is).. Which the TPI intake was meant to do..and the intake requirements of a 305 C.I. engine and those of a 350 C.I. at the same 5500 rpm are not that different that porting and port matching wouldnt help it come very close to being adequate for the intended application as stated by the OPand within his budget. within its limitations the TPI works very well.
Now a daily driver and part time autocross car would benefit more from bottom end grunt and mid range torque and throttle response than an extra 50 hp up at 5000 rpm.. so if your gonna be making power at 3500 rpm..why is that TPI so inadequate for this use at least in this stage of his game?
(BTW having no experience with "replacement TPI" doesn't mean I don't have any experience with TPI, )
As to exceeding the "published" CHP ratings of an LT4.. sounds like I may have committed some form of heresy there, beats me,
(that would be humor again) Shamdave good luck with your project.
Race Director
Joined: Feb 2004
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I am planning on rebuilding my engine...since i am an idiot (see shamdave and paint) and i insist on destroyi....i mean restoring my car my self here is my end goal. Please let me know your thoughts
I would like a driver that will light up the tires and cause some neck pain for my passenger,
I figure 300-400 horses to the ground would be good
I want to be able to drive it on vacation and melt the tires when i get there
It is an auto 85 with a tpi so here are my decisions
Carb or rebuild the TPI
What heads (new alumn re maned) or and machining do i do to the block?
Any one have any suggestions
Headers and exhaust?
will the trans and rear end be able to handle this? The trans was rebuild about 2 years ago.
I would like a driver that will light up the tires and cause some neck pain for my passenger,
I figure 300-400 horses to the ground would be good
I want to be able to drive it on vacation and melt the tires when i get there
It is an auto 85 with a tpi so here are my decisions
Carb or rebuild the TPI
What heads (new alumn re maned) or and machining do i do to the block?
Any one have any suggestions
Headers and exhaust?
will the trans and rear end be able to handle this? The trans was rebuild about 2 years ago.
But that's just me. Many good ways to spend $2500.
Race Director
Joined: Jun 2009
Posts: 10,428
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From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
they also sell a 9.5:1 motor that makes 435 hp.. http://www.summitracing.com/parts/EDL-45901/ at $7000 dollars these are complete motors, and that isnt a stroker or anything exotic..
So, sorry to disagree with you but it aint magic and it doesnt take "several expensive mods" to do it.. I would bet that if shamdave bolted those same parts on his existing L98 assuming its in decent shape and he would see similar results.
Race Director
Joined: Jun 2009
Posts: 10,428
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From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
thats the best idea yet.. can you get the bottom end of a 383 together around 2500 bucks? that would be the top solution if you could..
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,213
Likes: 2
From: Cincinnati oh
Ok here is what i am thinking after all the advice (BTW all of it appreciated) and some research i have done 2 things are for sure
HP cost money
and more HP Less dependable (not always but you see where im going here)
So here is what i am thinking
With an oil pressure problem (dropping DOWN to 2-5 PSI @ idle)
I am going to pull it and rebuild what i have
Some day this will go to my grandson on 12/10/2031 so it will need to last a while
Mild cam
Headers
Bored .30 -.35 over
have the heads ported and refreshed
Get injectors and clean up the plenium
Nix the AC and O2 Pump
Drive her till she pukes rebuild and start again!
HP cost money
and more HP Less dependable (not always but you see where im going here)
So here is what i am thinking
With an oil pressure problem (dropping DOWN to 2-5 PSI @ idle)
I am going to pull it and rebuild what i have
Some day this will go to my grandson on 12/10/2031 so it will need to last a while
Mild cam
Headers
Bored .30 -.35 over
have the heads ported and refreshed
Get injectors and clean up the plenium
Nix the AC and O2 Pump
Drive her till she pukes rebuild and start again!
Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Le Mans Master
Joined: Jun 2006
Posts: 5,642
Likes: 5
From: One day you're a Comet...the next day you're dust... Arkansas
Ok here is what i am thinking after all the advice (BTW all of it appreciated) and some research i have done 2 things are for sure
HP cost money
and more HP Less dependable (not always but you see where im going here)
So here is what i am thinking
With an oil pressure problem (dropping DOWN to 2-5 PSI @ idle)
I am going to pull it and rebuild what i have
Some day this will go to my grandson on 12/10/2031 so it will need to last a while
Mild cam
Headers
Bored .30 -.35 over
have the heads ported and refreshed
Get injectors and clean up the plenium
Nix the AC and O2 Pump
Drive her till she pukes rebuild and start again!
HP cost money
and more HP Less dependable (not always but you see where im going here)
So here is what i am thinking
With an oil pressure problem (dropping DOWN to 2-5 PSI @ idle)
I am going to pull it and rebuild what i have
Some day this will go to my grandson on 12/10/2031 so it will need to last a while
Mild cam
Headers
Bored .30 -.35 over
have the heads ported and refreshed
Get injectors and clean up the plenium
Nix the AC and O2 Pump
Drive her till she pukes rebuild and start again!
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Race Director
Joined: Feb 2004
Posts: 12,518
Likes: 19
Ok here is what i am thinking after all the advice (BTW all of it appreciated) and some research i have done 2 things are for sure
HP cost money
and more HP Less dependable (not always but you see where im going here)
So here is what i am thinking
With an oil pressure problem (dropping DOWN to 2-5 PSI @ idle)
I am going to pull it and rebuild what i have
Some day this will go to my grandson on 12/10/2031 so it will need to last a while
Mild cam
Headers
Bored .30 -.35 over
have the heads ported and refreshed
Get injectors and clean up the plenium
Nix the AC and O2 Pump
Drive her till she pukes rebuild and start again!
HP cost money
and more HP Less dependable (not always but you see where im going here)
So here is what i am thinking
With an oil pressure problem (dropping DOWN to 2-5 PSI @ idle)
I am going to pull it and rebuild what i have
Some day this will go to my grandson on 12/10/2031 so it will need to last a while
Mild cam
Headers
Bored .30 -.35 over
have the heads ported and refreshed
Get injectors and clean up the plenium
Nix the AC and O2 Pump
Drive her till she pukes rebuild and start again!
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,213
Likes: 2
From: Cincinnati oh
I will convert over my TPI and get a hot Dist and away i go
Le Mans Master
Joined: Sep 2006
Posts: 6,050
Likes: 147
From: Phoenix AZ
2021 C4 of the Year - Modified Finalist
Why not buy a stroker kit for about $1000 and a good set of heads for $1500?
the extras you will need are cam, gaskets, etc.
and a tune.
The tune would be around $200 and the gaskets about $100. Then there's hoses, etc.
Upgrade your intake and exhaust when you get another $1000-$1500 later. It will run just fine on the street with what you have.
the extras you will need are cam, gaskets, etc.
and a tune.
The tune would be around $200 and the gaskets about $100. Then there's hoses, etc.
Upgrade your intake and exhaust when you get another $1000-$1500 later. It will run just fine on the street with what you have.
Race Director
Joined: Jun 2009
Posts: 10,428
Likes: 9
From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
Do double check that oil pressure reading.. if you only have 2-5 PSI at idle hot, the lifters should be clattering like mad and that engine should be making all sorts of unpleasant noises.. It would be time well spent.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Here's what GM says in the 96 Owners Manual; page 2-89:
" Oil pressure should be 20 to 80 psi (140 to 550 kPa). (In certain situations such as long, extended idles on hot days, it could read as low as 6 psi (40kPa) and still be considered normal.)"
Remember, the oil pressure gage is NOT linear. So with the pointer at a mid-way position does NOT mean the psi is half way between the lowest and highest marks on the gage. Shown on page 2-96.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
" Oil pressure should be 20 to 80 psi (140 to 550 kPa). (In certain situations such as long, extended idles on hot days, it could read as low as 6 psi (40kPa) and still be considered normal.)"
Remember, the oil pressure gage is NOT linear. So with the pointer at a mid-way position does NOT mean the psi is half way between the lowest and highest marks on the gage. Shown on page 2-96.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
Thread Starter
Burning Brakes
Joined: Nov 2007
Posts: 1,213
Likes: 2
From: Cincinnati oh
Here's what GM says in the 96 Owners Manual; page 2-89:
" Oil pressure should be 20 to 80 psi (140 to 550 kPa). (In certain situations such as long, extended idles on hot days, it could read as low as 6 psi (40kPa) and still be considered normal.)"
Remember, the oil pressure gage is NOT linear. So with the pointer at a mid-way position does NOT mean the psi is half way between the lowest and highest marks on the gage. Shown on page 2-96.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
" Oil pressure should be 20 to 80 psi (140 to 550 kPa). (In certain situations such as long, extended idles on hot days, it could read as low as 6 psi (40kPa) and still be considered normal.)"
Remember, the oil pressure gage is NOT linear. So with the pointer at a mid-way position does NOT mean the psi is half way between the lowest and highest marks on the gage. Shown on page 2-96.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
Race Director
Joined: Nov 2003
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From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Who's tune are ya gonna bank on for $200?
Or do it now with ported heads!
Race Director
Joined: Nov 2003
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From: Overland Park Kansas
2020 Corvette of the Year Finalist (appearance mods)
C4 of Year Winner (appearance mods) 2019
Advanced
Joined: Oct 2003
Posts: 94
Likes: 1
From: Chattanooga TN
Here's what GM says in the 96 Owners Manual; page 2-89:
" Oil pressure should be 20 to 80 psi (140 to 550 kPa). (In certain situations such as long, extended idles on hot days, it could read as low as 6 psi (40kPa) and still be considered normal.)"
Remember, the oil pressure gage is NOT linear. So with the pointer at a mid-way position does NOT mean the psi is half way between the lowest and highest marks on the gage. Shown on page 2-96.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
" Oil pressure should be 20 to 80 psi (140 to 550 kPa). (In certain situations such as long, extended idles on hot days, it could read as low as 6 psi (40kPa) and still be considered normal.)"
Remember, the oil pressure gage is NOT linear. So with the pointer at a mid-way position does NOT mean the psi is half way between the lowest and highest marks on the gage. Shown on page 2-96.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
Le Mans Master
Joined: Aug 2007
Posts: 8,735
Likes: 414
From: WV
(It does drop to 2-5 lbs after it is hot @ idle.)
Read his post above again....He says his oil pressure drops to 2-5 lbs hot idle..(Nothing about Lost 4-5 lbs after hot)..And he is talking about running pressure being 30-40 lbs, not his idle pressure... If he puts a mechanical gauge on the motor and only has 2-5 lbs oil pressure hot idle...That ain't good..Oil pressure this low at idle can possible mean theres significant wear or some other problems....WW
Last edited by WW7; Jun 2, 2010 at 05:18 PM.
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
really? awesome it actually runs good no smokes or knocks the oil pressure is OK it runs about 30-40 after hot and holds good.
It does drop to 2-5 lbs after it is hot @ idle.
So what can i do to give her more go go and keep it dependable.
It has a performance chip and that about it not real sure where to go from there.
It does drop to 2-5 lbs after it is hot @ idle.
So what can i do to give her more go go and keep it dependable.
It has a performance chip and that about it not real sure where to go from there.
Please clarify thius: Does the oil pressure, when hot, drop TO 2-5 lbs OR does it only drop a total of 2-5 lbs? Big difference.
Jake
My son, Ryan M. Cameron, graduated from West Point on 22 May 2010! He was commissioned as a 2nd Lieutenant and I pinned on his first pair of "Butter Bars" PROUDEST DAY OF MY LIFE!!
Race Director
Joined: Jun 2009
Posts: 10,428
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From: Southside of Western Norte Americano State of Confusion, ColoFornia
St. Jude '13
Im thinking 2-5 psi oil pressure is too low at a reasonable 700 rpm idle. I wouldn't be comfortable with it.
Last edited by Bondami; Jun 2, 2010 at 07:11 PM.