L98 without TPI
Thread Starter
Melting Slicks
Joined: Dec 2008
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Likes: 64
From: Mystic CT
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
Is the prefered method for guys running big cube SBC's.Have put bosses in a SP and used 90 degree hat or made custom plenum.
Thread Starter
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Same as a MR meaning a loss in torque in the mid range and more top end? I had thought the ZZ4 used the same head thogh might be wrong there. Looking for 400 ft lbs and 375 hp or so in the end. Max rpm 5800.
Le Mans Master
Joined: Dec 2002
Posts: 5,270
Likes: 3
From: Seattle Area WA
Honestly, 5800rpm is pretty much dead nuts super ram territory. I don't know if you'd hit 375horse with it, but you can hit the tq (+) for sure. Lingenfelter claimed about those numbers for a 350 with the super ram, 219 LPE cam and ported 113s (yes, zz4 heads.)
However I've mostly seen the single plane on big cube SBCs and blown applications, I've been wondering how it would do on smaller motors.
However I've mostly seen the single plane on big cube SBCs and blown applications, I've been wondering how it would do on smaller motors.
Thread Starter
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
I just put on a Borla exhaust, front y pipe with no precats and a Magnaflow cat. It does have loud going for it now.. LOL.. But in driving around it feels great around town but when you get on it it starts to get going pretty good then nothing LOL at about 4 k rpm it seems to just give up the charge so lack of top end power in my mind. The usable power band seems to be 2k to maybe 4200 rpm then a black hole of ho hum nothing. It has new cap rotor plugs wires fuel filter O2 sensor trans fluid and filter rear end lube w/positracion fluid R134a underdrive pulleys. If it would pull as hard from 4k to 6k as it does from 2k to 4k it would be a lot more fun to drive. Looking at the GM website the ZZ4 seems to offer a ton more performance. My thoughts being the intake used was a simple single plane unit and slightly more cam. I am not real game on changing the cam yet but the intake swap seemes easy enough. After the endless Magnaflow exhaust debacle I am up for some simple things to do. It would also be a good place to start i think learning about tuning the 91 SD ECU. Brakes are next anyway but planing for winter projects. In the end i am sure heads and a better cam a must just not in the cards for me in $$$$...
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Le Mans Master
Joined: Aug 2000
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From: Australia
My take on it.
Going to a injected SP intake will have the same effect as putting a carb on. Engine will rev much higher.
But the 1st limitation will be the stock cam which is very wimpy because it is designed to work with the TPI which maxes at 4800.
Yes it will rev higher but will it make more power????
Thread Starter
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Once you take the TPI off it is just another SBC limited by whatever heads / cam it has.
My take on it.
Going to a injected SP intake will have the same effect as putting a carb on. Engine will rev much higher.
But the 1st limitation will be the stock cam which is very wimpy because it is designed to work with the TPI which maxes at 4800.
Yes it will rev higher but will it make more power????
My take on it.
Going to a injected SP intake will have the same effect as putting a carb on. Engine will rev much higher.
But the 1st limitation will be the stock cam which is very wimpy because it is designed to work with the TPI which maxes at 4800.
Yes it will rev higher but will it make more power????
Does anyone know the spec for a stock L98 cam?
Thread Starter
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Melting Slicks
Joined: Feb 2006
Posts: 2,753
Likes: 15
From: backwoods upstate ny
congrats...you've just (re)discovered ''the wall'' that us 'ol ferts' found back/day with 305 targeted tpi on a 350...trash that 305 intake and put an intake from an lt1 on, car runs sooo much better, PULLS all the way to 'lifter float'.
Instructor
Joined: Jan 2009
Posts: 170
Likes: 1
From: Crofton MD
I just put on a Borla exhaust, front y pipe with no precats and a Magnaflow cat. It does have loud going for it now.. LOL.. But in driving around it feels great around town but when you get on it it starts to get going pretty good then nothing LOL at about 4 k rpm it seems to just give up the charge so lack of top end power in my mind. The usable power band seems to be 2k to maybe 4200 rpm then a black hole of ho hum nothing. It has new cap rotor plugs wires fuel filter O2 sensor trans fluid and filter rear end lube w/positracion fluid R134a underdrive pulleys. If it would pull as hard from 4k to 6k as it does from 2k to 4k it would be a lot more fun to drive. Looking at the GM website the ZZ4 seems to offer a ton more performance. My thoughts being the intake used was a simple single plane unit and slightly more cam. I am not real game on changing the cam yet but the intake swap seemes easy enough. After the endless Magnaflow exhaust debacle I am up for some simple things to do. It would also be a good place to start i think learning about tuning the 91 SD ECU. Brakes are next anyway but planing for winter projects. In the end i am sure heads and a better cam a must just not in the cards for me in $$$$...
Thread Starter
Melting Slicks
Joined: Dec 2008
Posts: 2,772
Likes: 64
From: Mystic CT
Thats crazy! I was planning on changing my exhaust soon, so far everyone has said this is the first upgrade worth doing for not a lot of cash. Ive never heard anyone say that swaping exhaust killed their top end, my understanding was an increase in power through the whole power band. So was your car stronger 4k rpm and up before the swap?
