TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
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Yeah, no new news for the TPI. If anything parts are starting to get discontinued. The development curve went flat on these cars about ten years ago. Everyone is sinking their R&D money into the LS1/LS2/LS7 engines now.
If it's a good deal then buy it. You can still get these new, but they are over $400 I think. If I was going to change intakes on a TPI I'd use the TPIS Mini Ram, but it all depends on what you want to do with the car. A better base and runner will get you about 20HP over stock, but if you want big power the stock style TPI intake is going to hold you back.
im in the middle of planning a build and this intake just popped up. was planning on using a edelbrock or tpis. still trying to figure out a cam and head setup.
car is going to be a daily driver so i dont want to kill my MPGs and still have enough for occasional good numbers from the track.
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87 IROC L98, 700R4, 3.27 gears, 3" Hooker CAT-back, UMI panhard bar, UMI rear lower control arms, Energy Suspesion bushings, K&N, Walboro fuel pump, KYB rear shocks.
How much power are you looking to make? Are you building a stroker? If you are looking for over 350HP and/or are building a 383 I would advise against a TPI style intake and suggest the TPIS Mini Ram. The cost will be the same as upgrading to a full Accel intake system, and the Mini Ram will still outperform it. Using just the base and the rest of the stock TPI will be a major restriction and effectiveyl choke out a 383 or even a high winding 350 at RPM above 5,000.
If it's a mild build I say go for it, but if you're looking for more like what I'm talking about above I'd pass. The wrong part for the right price is still the wrong part.
its going to be a mild build daily driver. my plan is to port the plenum to a set of AS&M runners and pick up an aftermarket base. going to get a set of edelbrock performer heads and an LT4 hot cam. have a set of hooker 2055s as well and hi flow magnaflow cat.
car is going to be a daily driver so im not looking to lose my drivablity but still have some power to play w/ occasionally at the track.
its a budget build so want to keep the cost down as much as possible.
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87 IROC L98, 700R4, 3.27 gears, 3" Hooker CAT-back, UMI panhard bar, UMI rear lower control arms, Energy Suspesion bushings, K&N, Walboro fuel pump, KYB rear shocks.
Rethink the cam. The LT4 Hot cam is designed for an LT4, which uses a short runner LT4 intake and is designed to make peak power above 6,000 RPM. Even with a ported plenum, runners, and a base you are not going to flow air above 5,800 RPM. The Performer heads are going to be done at 5,500. I would look to make peak power at 5,500. Plus, I'm not sure what the LCA is on the Hot cam, but my guess is it's wide. For an engine with a powerband from 1,500-5,500 you want a 112 or 110 LCA. They may have widened up the LCA on the Hot cam to 114 or more to get it to run right with the stock electronics. This is supposition as I do not know the exact specs, so double check for yourself.
I'd look for a cam with .488 lift, a 112 degree LCA, and 260 degrees of advertised duration. I like Crane for roller cams. They make a good selection with good figures. You will want a little more exhaust duration and lift. The Performers flow well and have a good I/E flow relationship, but you still need a little more exhaust airflow.
no cant say that i have given up on it. still weighing options. trying to getthe best drivability setup as possible since it will be a daily driver. want to maintain as much of the 17-20 mpgs i get now.
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87 IROC L98, 700R4, 3.27 gears, 3" Hooker CAT-back, UMI panhard bar, UMI rear lower control arms, Energy Suspesion bushings, K&N, Walboro fuel pump, KYB rear shocks.
As long as you don't change the rear gear your highway fuel milage should be the same, maybe better if you lean out the part throttle cruise in the fuel map. Just keep the part of the map where you are going to be running hard safe at about 12:1 A/F ratio at peak power. During spirited driving you will get less milage than you do now. Fuel makes power, there's no way around it. But your cruise mileage shouldn't decrease if you burn the chip right.
Rethink the cam. The LT4 Hot cam is designed for an LT4, which uses a short runner LT4 intake and is designed to make peak power above 6,000 RPM. Even with a ported plenum, runners, and a base you are not going to flow air above 5,800 RPM. The Performer heads are going to be done at 5,500. I would look to make peak power at 5,500.
I believe you need to rethink that about the LT4 Hot Cam.
I have one out there in a 350, Edelbrock base & runners, corvette heads (ported) and shorty 1 3/4 headers making over 300 to the rear wheels @ 6000
'91 GTA auto
so matter what setup i put together the key is the chip tune? i planned on a chip tune hopefully on a dyno instead of mail order chip.
A dyno tune will not likely help your DD MPG, the cruise has to be tuned first then the WOT/PE.
"a cam with .488 lift, a 112 degree LCA, and 260 degrees of advertised duration"
The Comp cam (XR258HR-10) 110 LSA , 480 lift and a 258 Ad dur is what I run in my DD. It is good for 1000 - 5000 rpm. Gets 20 mpg HW and 15-18 driving to work. It has enough to toast a stock 700R4. I also run the "hated" Edelbrock performer heads with 70cc chambers on 87 octane 10:1 CR.
At 55-60 mph I turn 1700 rpm in OD 255/50-16 tires and a 3.07 RG.
Your car should turn maybe 500 more rpm due to tires and 3.26 RG. So maybe more duration could be used, say 1500 to 5500 rpm range.
I run a stock TPI intake but the accel will help your higher rpm's.
Note that the guys that run a 3.73 RG are running the higher rpm cams.
Like was said before it is about your budget and your goals.
If you change your mind about using the accel, sell it to me.
the accel base fell through and looks like i will be using the edelbrock base w/ either edelbrock performer or e-tecs. the cam i may be running now is the comp 08-305-8. im not buying anything till i know its the right setup.
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87 IROC L98, 700R4, 3.27 gears, 3" Hooker CAT-back, UMI panhard bar, UMI rear lower control arms, Energy Suspesion bushings, K&N, Walboro fuel pump, KYB rear shocks.