TPITuned Port Injection discussion and questions. LB9 and L98 tech, porting, tuning, and bolt-on aftermarket products.
Welcome to ThirdGen.org!
Welcome to ThirdGen.org.
You are currently viewing our forum as a guest, which gives you limited access to view most discussions and access our other features. By joining our community, at no cost, you will have access to post topics, communicate privately with other members (PM), respond to polls, upload content and access many other special features. Registration is free, fast and simple, join the ThirdGen.org community today!
I know a lot of the TBI guys run LT1 cams, does anyone have an LT1 cam in an LB9?? I really don't want to dish out $300 for a roller cam when I have a stock 1993 LT1 cam laying around, and it is considerably bigger than the peanut cam that is in the car now. Also, will LT1 valve springs work with the LB9 heads? I also got a set of Crane .550 lift single springs for an LT1 which would go on when I did the cam swap. The lift on an LT1 cam is around .460, so are the springs going to be too much???
BTW, why do people say that the LT1 cam is just a step up from the LB9 cam? Here are the specs
Peanut Cam - Duration at .050: 179/194 Lift: .350/.384
LT1 Cam - Duration at .050: 202/207 Lift: .450/.460
That is a huge step in my opinion when it comes to cams.
This ad is not displayed to registered members. Register your free account today and become a member on ThirdGen!
__________________ '87 White Iroc Z - Totalled for minor cosmetic damage, rebuilding in process.
A few years back I put a 93' LT1 F-body cam in an 88' 5 speed car (single cat, non-G92). Small upgrade while the motor was out - but it seemed to like it. (And yes, I know the M5 cars had a bigger cam that the A4 cars).
The way I see it, you can get a used LT1 cam dirt cheap. And your car will idle/run fine on the stock tune with that cam. I would go with it. As for valvesprings, I think LT4 hot cam springs are pretty cheap. They fit the stock pockets and are good to .525" lift. The .550" lift springs would be a bit overkill.
Yeah that is what I was thinking on the springs. I will probably just replace them with new LT1 valve springs which are the same part number as new replacements for the LB9. They are Sealed Power VS677. They are about $2.50 a piece.
Being your car has a peanut cam, it will wake up more so than that 5 speed car did IMHO. What does your car run now with the current mods? I had an 89' IROC vert in the late 90's. It had: PI 2600 converter, rebuilt 700R4 w/ a Transgo, Borla CB, air foil, ported plenum, UD pullies, LCA's & PHB, K&N's, gutted air box, !smog pump, !cat, 3.23 gears.
I ran 14.3-14.4 @ 96+ on BFG drags. 14.60's on street radials. Still had stock manifolds and the wimpy peanut cam. I felt the car had 13.90's in it with a cam swap and a good set of headers, but never got around to it.
There's no telling if your engine actually has the peanut cam unless you check it with a dial indicator. I have seen people with '87 TPIs on this board claim both camshafts in their car.
As the car sits right now it runs a 8.90's at 81 in the eighth mile. Cant spray until second though. That is with street tires and a 2.73 gear. Other plans are to complement the cam with a 3.42 gear and a afpr. What fuel pressure should I run with that setup and a set of 22 lb injectors???
A guy told me that a 80 mph trap in the 1/8th will get me mid to low 13's in the 1/4, but theres only one way to find out and there are no 1/4 mile tracks within about 1.5 hours from here.
Last edited by WhiteIrocZ; 04-12-2008 at 12:24 AM.
i have an 88 iroc 305 tpi auto. i have since converted it to a t5 and i put in a l98 tpi cam, so i had the peanut cam and i am going to the biggest cam made in thirdgens, it is still a small cam but i am building this car as an everyday driver so i didnt want anything aggresive and i didnt wanna spend $300 for an aftermarket, i wanted the lt1 cam but a mw66nova had a l98 cam and he lives just up the road from me. so i bought that and put it in. the motor is assembled but not in the car, i am shooting to have the motor ready to go in the car before work tomorrow and then stick it in tomorrow night, i am shooting to have it running monday afternoon (have to work all day sunday too..) i am going to keep the motor completely stock with the exception of the l98 cam, but i am going to add on pieces later on to see how they helped, i am eventually going to go with 1.6 rr's, afpr, slp runners and diy port upper and lower intake that is probly all i will do to this engine b/c i am going to be driving it everyday but i want to do those mods individually and see how much i gained from them. but i will update yall once its running and i also am going to be racing it on the 20th so ill post some times.
the car ran a 15.4 completely stock that is with the 305 tpi auto and 2.73 gears but that is when i had just bought the car and it sat for 2 years, it needed a tune up something terrible trap speed was 88 mph. here is my new setup what do you guys think it will run?
305 tpi with l98 cam, t5 and 3.45 gears, with a 100 hp shot and a set of worn out 26" slicks, edit: i am also going to have an msd 6al and a two step for launching, and probably a set of underdrive pulleys
i am hoping for 14.80's or better on motor and 13.9's or better on the 100 shot. what do you guys think?
Definitely budget headers in. I bought Hedman shorties with a Y for $250 and the gains were well worth it. I am not sure what it actually gained, but the car sounds better and is much better to drive. It improved low end torque as well as high end power. It doesn't seem to drop off as much at 4500 after the headers and Y. That car should be much faster than mine considering bigger cam, 5 speed, gear, bigger shot, and slicks. It should run low 13's if you can drive it.
I had to come up with something different seeing as my 86 was a non roller, but I've found the Melling RV cam works really well with the TPI setup, and coincidentally, it's almost identical to the 350 cam in the 92 Z28. just a thought.
The springs I was considering are only good to .450 lift, so that is out. I already have .550 lift springs, would it really be bad to run that big of a spring? They are just a single spring with a damper. What would be the downfalls of running that spring???
The springs I was considering are only good to .450 lift, so that is out. I already have .550 lift springs, would it really be bad to run that big of a spring? They are just a single spring with a damper. What would be the downfalls of running that spring???
They're just overkill, but if you already have them - use them. In rare cases, you might collapse a lifter if they are high mileage with the added spring pressure. What are the specs? Seat pressure, and open? More than likely you'll be fine, but I would replace the lifters during the swap for good measure.
I would rather buy springs than lifters, but then again I may have a lifter going bad because I recently changed to 5W-30 oil after I replaced my valve stem seals and now I have a ticking in the motor. I am pretty sure it is a lifter because there are no exhaust leaks, and it increases with RPM. I am going to switch back to 10W-40 and see how that does.
The springs I was considering are only good to .450 lift, so that is out. I already have .550 lift springs, would it really be bad to run that big of a spring? They are just a single spring with a damper. What would be the downfalls of running that spring???
Spring lift isnt critical when using a stock cam, its the spring pressure when closed and when open that will matter. If they're stock size 1.25" springs I dont think you can get too much pressure to mess something up. They should be in the 110-130 range when closed and 300 when open.
Recommended Camshaft Style Roller hydraulic Installed Height (in) 1.750 in. Seat Pressure at Installed Height (lbs) 108 lbs. Open Height (in) 1.250 in. Open Pressure (lbs) 339 lbs.
I believe they are these Lunati springs. Take a look and see what you think. http://store.summitracing.com/partde...5&autoview=sku
I may end up with these Sealed Power springs from advance. They seem like a better choice. Here are the specs. Check em out. http://www.northernautoparts.com/Pro...ctModelId=2297
Last edited by WhiteIrocZ; 04-17-2008 at 12:45 PM.
So back to the original question. Does anybody have a straight answer for this? I have a 1987 350 TPI (IROC-Z) with roller lifters, non roller rockers, EDL-5894 SPRING KIT. Now with that said, can a LT1 cam from a 1994 Z-28 be installed into the factory ECM without any tuning? Does anybody have an answer to this question?
