hi all, i have a couple of questions for you TPI gurus,right now i have a 84 Z28 with a 350, port matched the heads with a Weiand Xcellorator intake, Edelbrock Performer 600 carb, Crane 278H10 cam(278* duration .467" lift)stock manifolds, 2.5 dual exhaust with homemade round mufflers, Desktop dyno says its makin 340hp, and last nite i got it up to 150mph, and it was still gaining speed at about 3/4 throttle. this engine really likes to get goin past 2500 rpm. im going to be installing a speed density TPI system, im going to port everthing i can on it before the install, and polish the system. i would like to know what all im gonna need to do the install, the TPI is complete with computer and wiring. how long am i lookin for the install(im an experianced wrech turner)and what kind of gains or losses am i gonna have installing tuned port, Desktop Dyno shows im losing about 40hp and not getting any more torque, but i thought i would ask people who have it. do you think i will gain hp, i know i will get alot more torque out of it, i just dont want to have my car be any slower, only faster. right now i have the fastest car at my highschool and i would like to keep it that way. thanks for your replys

 

For now then...keep the carb...

The deal is that you would have to spend quite a bit of $$$ to get a good modified TPI setup...plus the fuel system mods...not to mention that your cam (I am sure) has a 110 LSA or less (which the SD setup won't like) and you want a cam with 112 or 114 LSA .

If you are looking at swapping on a stock TPI setup...definitely wait...

The carb, when properly tuned is the better way to go for you...especially on a budget...

I am glad my vehicles in high school were carbed...much easier and cheaper to diagnose/fix...sigh...the good old days..

 

what do you mean the SD setup wont like my cam? so your saying that fuel injection is not good for me? damn i want the ease of not having to wait in my car so that it will idle by itself in the morning, and i want good throttle response too, which my setup has none cause of that intake and carb.sometimes the car will "shutter and bog" when i pour the coals goin slow. so you dont think that even with massive porting that it wont work out for me, also it will be awhile before i would install the TPI so by then i would prolly have a new cam better suited for that. wouldnt i gain alot of off the line power with the TPI? thanks

 

Hold on...one question at a time here...

First of all...post your EXACT cams specs including LSA....

Second...if you are talking about carb tuning (or lack therof) that is a different question for the Carb board...

Third...a stock TPI setup is not going to provide lots of additional torque...

The reason is that a properly tuned carb setup can provide great torque/HP...that is the key...

 

Here are the specs for your cam:

Specifications:
* Advertised duration: 278 intake/290 exhaust
* Duration at .050 in.: 222 intake/234 exhaust
* Gross Valve Lift: .467 in. intake/.494 in. exhaust
* Lobe separation: 114 degrees
* RPM range: 2,500 to 5,500
* Good idle, daily performance usage
* 3,000-3,400 cruise rpm
* 9.5:1 to 10.75:1 compression ratio recommended.

I am not a tpi guru but from what I have read here and in some books, that cam will not be a good match with stock LTR's even with porting.

 

That cam is a bit for a stock TPI...but it is surprising that the LSA is so high...that cam should work fine with SD...the key is a good LSA for a proper vacuum signal for the MAP sensor...

I still think that swapping to EFI won't be worth it for you right now...too much cost for too little gain...

 

My bad Here is the correct specs:

Degrees Duration @ .050 Int./Exh. Degrees Advertised Duration Int./Exh. Degree Lobe Separation Open/Close @.050" Cam Lift Int./Exh. Lash Hot Int./Exh. Gross Lift Int./Exh.
222
222 278
278 110 6 36
46 ( 4) .000
.000 .467
.467

Link to spec card:


http://dab7.cranecams.com/SpecCard/D....asp?pn=100132

 

Frankly...a single pattern cam isn't the best choice with stock heads anyway...the exhaust ports are too restrictive and an exhaust duration of 5-10 degrees more would be helpful..

That cam does have a 110 LSA...that would make it pretty tough to tune a SD setup or even MAF with a tight LSA like that...

All of this still means...keep the carb for now and tune it properly...when funds allow, upgrade to a better set of heads and you should be making 420 HP...

Also, Desktop Dyno is a bit optimistic and i would shave off about 20 HP...but the fact remains that it is a decent combo...

Spend the money on the heads/swap...

 

cool thanks for the great info, now i have to move to another board to have some people recommend heads for my app. thanks again