Advise Needed on LT1 Intake conversion
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
I've been awaiting an explanation on the relationship between the alleged 10 degree cam timing retard and the 4500 RPM power drop too.
Years ago, when I owned a 86 TPI Vette, I did some research on it's power bottle-neck, which I'll share once the above has been cleared up.
Jake
Years ago, when I owned a 86 TPI Vette, I did some research on it's power bottle-neck, which I'll share once the above has been cleared up.
Jake
Thread Starter
Instructor
Joined: Jan 2010
Posts: 177
Likes: 0
From: Orange County CA
So far I have not been able to confirm this but I am not doubting its true... I am running a Performance Cam in my Built L98 so I'm not concerned.
Just a thought, but if the cam timing was holding the L98 to 4500, why not just advance the CAM timing and run the TPI intake all day long at 6500 RPM??? Seem like the best bang for your buck
It's well documented that there is no comparison in Torque/Horsepower between the LT1 and TPI and actually the Horsepower gains are almost Identical to the mini ram. From what research I have done is that the TPI runners are known for there great low end torque and are what limit the L98 from making power at higher RPM's
Just a thought, but if the cam timing was holding the L98 to 4500, why not just advance the CAM timing and run the TPI intake all day long at 6500 RPM??? Seem like the best bang for your buck
It's well documented that there is no comparison in Torque/Horsepower between the LT1 and TPI and actually the Horsepower gains are almost Identical to the mini ram. From what research I have done is that the TPI runners are known for there great low end torque and are what limit the L98 from making power at higher RPM's
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
Thread Starter
Instructor
Joined: Jan 2010
Posts: 177
Likes: 0
From: Orange County CA
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,063
From: altered state
St. Jude Donor '05
Its the runner length that limits the rpm...the fact it was designed for a 305 doesnt help. On the GM retarding the cam thing Id have to see some proof of that I find it hard to believe. Most cams you install 10deg retarded it wont even run.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
btw, what is the 'intake CL' noted on the cam timing card from your 'perf cam'...lemme guess, 106* ATDC (maybe a degree either way)...degree your oem cam and, lemme guess again, oem it was 116* int CL
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
the dist is fully supported and aligned by the block , not the intake which only serves as a hold down point.
If you make the hole in the intake slightly OS you can mock it up and weld the spacer in the correct location/angle rather than trying to guess where to position spacer
Last edited by rodj; Feb 2, 2010 at 08:52 PM.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
Melting Slicks
Joined: Apr 2007
Posts: 2,616
Likes: 111
I always thought the wall at 4500 RPM is related to the L98 intake of course........LONNNNG RUNNERS!!!!!!!
should have just "re-degreed" my stock cam and ran that bitxx up to 6500 RPM with no choking.......would have saved myself a lot of headaches and cash
Last edited by 856SPEED; Feb 2, 2010 at 09:20 PM.
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
Melting Slicks
Joined: Mar 2002
Posts: 3,108
Likes: 126
From: S.L.C. UT
The runner length is just too long to support any high rpm hp. And as mentioned, it was designed for a 305.And there is a forum member on here that had a converted LT1 intake that the dist hole wasn't deep enough, and it just barely was deep enough to drive the oil pump. Well on the dyno, it lost oil pressure and took out the engine because the distributor didn't have enough grip on the oil pump drive rod. And there was alot of other problems he ran ito to make a LT1 intake work on a first gen SBC.
I would go with a miniram, bolts right on, and everything is engineered out of the box to work. And the miniram has much bigger intake plenum and runners. If you look at the two side by side, there are alot of big differences.
Team Owner
Joined: Dec 2007
Posts: 20,974
Likes: 261
After reading tpi 421 vette post, and you go cheap with a cobbled LT1 intake, you should know you were warned how easy the miniram is. Sure some have it, some have shops, and tools to make stuff work right, not that you don't but...
Thread Starter
Instructor
Joined: Jan 2010
Posts: 177
Likes: 0
From: Orange County CA
Jake ,
the dist is fully supported and aligned by the block , not the intake which only serves as a hold down point.
If you make the hole in the intake slightly OS you can mock it up and weld the spacer in the correct location/angle rather than trying to guess where to position spacer
the dist is fully supported and aligned by the block , not the intake which only serves as a hold down point.
If you make the hole in the intake slightly OS you can mock it up and weld the spacer in the correct location/angle rather than trying to guess where to position spacer
I see you have a skinny distributor mocked up in your pic. Did you end up running that setup on your corvette? If so, what did you do to convert the HEI style wiring over for these connections?
Thanks,
Mike
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
QUOTE=856SPEED;1572966811]; WELL SAID BECAUSE THAT IS ONE OF THE STRANGEST POSTS I HAVE SEEN! QUOTE]
STRANGE is putting it mildly!
One link says the LT1 intake has to have a distributor hole precisely drilled, yet another post says it doesn't matter and references "wiggle room".
Then we have the 10 degree cam retard assertion, where, on another thread, a stock cam is being compared to an aftermarket cam, each having different LSAs. The conclusion being drawn is that the stock cam is 10 degrees retarded. WOW! LOL
Maybe it's just a test. LOL
Jake
STRANGE is putting it mildly!
One link says the LT1 intake has to have a distributor hole precisely drilled, yet another post says it doesn't matter and references "wiggle room".
Then we have the 10 degree cam retard assertion, where, on another thread, a stock cam is being compared to an aftermarket cam, each having different LSAs. The conclusion being drawn is that the stock cam is 10 degrees retarded. WOW! LOL
Maybe it's just a test. LOL
Jake
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Mike at www.eficonnection.com ( amounst others) does a adapter harness ($15) to connect from the big HEI harness connector to the small F-Body type dist so no cut / splice needed and your wiring stays stock.
You also need the 2 wire coil pigtail ($10) to connect your remote mount coil
See
http://www.eficonnection.com/eficonn..._pigtails.aspx
Pro
Joined: Feb 2007
Posts: 740
Likes: 2
From: San Antonio TX
I don't know if it well work on you're aplication. Are the end adapters screwed on? You might need a remote regualator..
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Aeromotive make several stock replacement LT1 regs like #13107. You can remove the return fitting made for stock hard lines and use a -6AN fitting for braided lines
If the end of the rail is already threaded you can just screw a # 13301 straight into the rail
( use heavy EFI 20- 65psi spring )
Pic shows a connection to other rail for balance; bypass return is at bottom
If the end of the rail is already threaded you can just screw a # 13301 straight into the rail
( use heavy EFI 20- 65psi spring )
Pic shows a connection to other rail for balance; bypass return is at bottom