Another TPI thread - First one in mods tho!

[klb76]

Alright I have had enough with just fixing the 'vette its time to get something "fun, thrilling, exciting"! (I justify this because I have to replace/rebuild the carb anyway) I have decided I am going to go with a Fuel Injection system on my 76 L-82... but... (isn't there always a but?) When I bought the car there were already modifications to the engine which I imagine are going to cause me some problems, and and possibly help too... here is what I have to the best of my knowledge... top down

-Large Holley Air-cleaner
-650 Holley DP
-Edelbrock Torker Intake
-Accell HEI Super Coil 8mm wires
-Headers
-and I think an after market cam...

Well, I slid the cam thing right in there huh? I know the cam is really important for TPI at least, but will it be impossible to use any fuel injection without a mild cam? (I could always change the cam) The reason I believe it is different is because it is only logical that when everything else was bolted on they would have put a new cam in, and also my low end isn't so hot, nothing like the 3000-5000 RPM range... Since this is my first big project, and I decided to keep my M-21 tranny instead of switchin for 700R4, I don't mind spending a little money on this... I am thinking around 1500$... anyone have any ideas? Edelbrock has a nice system for abour 1900$ I noticed and I think I could make the switch to TPI for under $1500... and how can I tell what the specs are on the cam I have? any and all help is appreciated!!!

klb

 

[klb76]

Well I have been doing my research and here is what I come up with, The Holley Commander system and The Edelbrock Multi Port system seem to be about the same in overall performance.... The Holley system is substantially cheaper, however you would need a laptop to program it... which I could probably pick up a lap-top just for the car for about 100$... and the Edelbrock system is more appealing to the eye in my opinion... One problem is I know Accell has a fuel injection system out there and I can't seem to get any good info on it? I think 69MyWay has the edelbrock system, and judging from his threads he is happy with it, does anyone else have that system and how are thier results? Anyone have any of the other fuel injection systems?

klb

P.S. The Edelbrock guys gave me some hints on how to figure out my cam, that will be a load off my mind...

 

[klb76]

I think I have made my decision to go with either a GM TPI set-up or else the Holley Di system... both have thier pros and cons for sure... I really like the idea of using a laptop on the car (might seem like a ricer thing i know) but then agian I don't think much can compare with the looks of TPI for the price, and i hear the low end is amazing which performance wise is what I want.... So, I know what Holley system I would use, but I am not sure on the TPI, I have heard speed density is better, and i think that is on later then 87 TPI, but are all smallblock intakes the same?

~will a 305 intake/setup work on my L-82?
~would I be better off getting TPI off of another corvette?
~what was the best GM TPI set-up made that I can use on my L-82?

klb

 

[KANE]

Seriously-

Get the GM TPI

I installed my TPI back in '98 and have never looked back. Lets face it- a toilet that flushes gasoline is a carburator. They both have seats, floats, a lid and are prone to flooding due to user error. I would never go back to a carb. Yeeech.


***************************************
ADVANTAGES-
The 91 style speed density systems use a 256K processor. State of the art, even by today's standards.

You can find electronics and sensors for cheap at ANY parts house. No calls to the aftermarket manufacturer and waiting for weeks on a replacement part.

TPI has been around forever, so there are lots of parts for cheap. I think that the bottom has fallen out of the market though- so donb't expect prices to fall any farther.

Easily upgradable. Even tried and true techniques for carb engines like roller rockers are applicable. Chips can be burnt for less than $100.

TPI pretty much maintains itself. Only tweaking required or component replacement. Voltmeters, a scan tool (even a jumper wire will do in most cases) and the right literature will answer all your questions.

Unless you screw around with your injector size its hard to "over jet" your motor. Even then all you need to do is adjust your fuel pressure regulator.

Trouble codes via check engine light. It won't ever be flawless, but it will point ya in the right direction.
***************************************
DISADVANTAGES-
True, you can't "dial in" the performance from a laptop like Holley or Edelbrock.... but then again the average guy doesn't have the technical expertise or time to do it anyway.

Fuel lines, radiator hoses, accessories and clearance issues will kick you in the pants. You become really good at using your imagination to get things to fit sometimes.
***************************************
Words of advice-
USE A '91 VETTE ALTERNATOR AND SWAP PULLEYS AND REPLACE THE CONNECTOR. Otherwise your puny 60amp deal won't hack it.

Use AN fittings. Compression fittings are garbage. YOU WILL BE DRIVEN UP A WALL IF YOU HAVE FUEL LEAKS IN THE TPI'S PRESSURIZED SYSTEM!!!!

I recommend using an external fuel pump unless you really like dropping your gas tank. Yuck on Corvettes- spare tire carrier and associated junk.

READ, READ, READ! Do your homework and get to know how EFI works. Call and talk to everyone you can about how TPI works.

And for God's sake- BUILD IT YOURSELF. Two reasons: you'll have no one else to blame- and you will know every inch, where every wire is, and what parts are located.

 

[klb76]

Alright I just can't decide what I like best... if I had two cars I would have the holley system on one and the TPI on the other... so I guess what I am gonna do is give it about 2 weeks, and shop around... if the right price comes up for either I am gonna jump on it... I have been toying with the idea of putting a bird catcher on top of the Holley system which I think would look really sharp... but so would a powdercoated TPI.... hmmmm....

klb

 

[klb76]

I have been searching all over and can't seem to find this simple answer... What makes, models, and years can I use for TPI... If I go the TPI route I would like to go with a corvette speed density system, but I know the intakes changed somewhere in there... I think speed density was post '88? not sure about that either?

Thanks
klb

 

[72Slydog]

Hey Guys....Check www.chevythunder.com for lots of information on TPI.

 

[KANE]

SPEED DENSITY- officially used from 91-92, but you can convert the MAF cars to MAP fairly easy.

 

[69MyWay]

KLB, This is a tough call, because there are so many options.

For example, I just got a line on a complete 1995 LT1 from a F body (aluminum heads) with computer and the electronic overdrive trans for $850. Hmmm, that means a fellow could buy the aftermarket harness, reprogram the computer, purchase the accessory brackets and have a fire breathing 300 hp LT1 lurking under the hood of his shark for virtually the cost of just an EFI and supporting software systems.

Bottom line is, there is no one perfect answer. I love my EFI system, and the ease of reprogramming with the dedicated module. No lap top or expensive delicate electronics to toat around in the car. The programmer fits in the rear cubby and I can pull it out any time I want, take a look at what is going on in the computer and make the changes I desire.

Having a system compatable with a laptop is also very cool, if not just for the eye appeal at a car show (have it logged in on the front seat). It will blow people's minds, and you don't even have to start the engine.

The TPI system will work great, but you will be limited for overall peak power and performance. I have a complete 1990 speed density L98 sitting in my workshop (I mean complete engine, heads, intake, manifolds) only needing a harness, computer, fuel lines and accessories to be running in another car. I would sell the whole thing running and ready to go for $1,000. So you see, decision decisions.

You can get burned if you are not careful. For example I also have a 1988 F body TPI intake with a bad runner (engine fell over and it got crushed) that I would sell for $100. Then however, you would need at least one new runner, injectors, harness, sensors, new/rebuilt t/b, distributor, etc. etc. etc. and end up with $1,000 just making the intake work.

You can make any of the intakes work, but are better off with the 1988 and newer models that don't have the 9th injector for the cold start mode. You will have to hog out the center bolts with your dremel to get the newer intake to fit your heads. I have done it before, and it is a piece of cake.

You will be blown away by the torque your motor will make at the least little blip of the throttle with a stock TPI (oh, 305 and 350 are exactly the same less the injector size). However, I would guess you will be wanting more because with a stick shift trans you will be hitting the glass ceiling of the TPI intake quick (they run out of breath around 4,800 rpm). So, the next upgrade will virtually require replacing almost everything to get into a system that really breaths. I have the TPIS miniram on my 90 Vette and still can't get the grin off my face from the first time I nailed it and got rammed in my seat all the way to 6,000 rpm. What a difference the intake manifold design can make.

So, I am not really doing any more than confusing you more. I do agree however that the best darn looking manifold hands down is the stock TPI. Not to mention you can get it up and running with less guess work, less money (if you plan right), and have gobbs of low end torque to smoke the tires at a momements notice.

 

[klb76]

Well... if nothing else, through all my research I have learned nothing is easy with a vette.... I had sneaking suspicions that my motor had a little work to it by the sound of the cam, so when I had it at the shop last I had the mechanic look into it. (I can do most mechanical stuff but I step back when the engine starts coming apart) Well this is what he told me, It is bored out some, "3/4" cam, new heads... and i think some other stuff... and he said it looks like it was all done professionally. Well I think it is clear that TPI will not work for me now, just the cam alone is going to cause some serious problems... so I am looking at an aftermarket systems now.... and I am hoping to keep the cost under 2000$... any recomendations from anyone with some experience out there? I know I am gonna have to have my engine checked out again, to get some actual numbers. I've decided to get the car painted first so I am probably looking at a spring break (college kid) project with the fuel injection. I would hate to make an uneducated decision on a system and regret it and when I get some new color at least I won't be too embarrassed to take pictures...

klb

 

[KANE]

Anyone got a line on a USED Mini-ram?

I REALLY DON'T WANT TO PLUNK DOWN THE CHANGE FOR A NEW ONE!!!!

I guess I am kinda cheap. No- that's called being a smart shopper. Or at least thats what the best shopper I know says.... and thats mom, of course!

 

[69MyWay]

Anyone got a line on a USED Mini-ram?

I REALLY DON'T WANT TO PLUNK DOWN THE CHANGE FOR A NEW ONE!!!!

I guess I am kinda cheap. No- that's called being a smart shopper. Or at least thats what the best shopper I know says.... and thats mom, of course!

Keep an eye on TPIS. They have a garage sale section. I bought my miniram from them used with a decent discount. They cleaned it up so nice you could not tell it had ever been installed.

 

[KANE]

This is for anyone who wants to do a TPI conversion-

STAY AWAY FROM THOSE TERRIBLE COMPRESSION FITTINGS!!

I tried those things for the last 5 years. Ughhh. Never again will I mess with those unreliable, leaky, worthless things. Long live the AN fittings. Yes, they are expensive... but well worth it. Chunky looking- yes, but they seal!

I realize that its all about technique when it comes to how you crack the nut of getting fuel lines from the car to the motor, but this has paid dividends for me.

Hope this gives someone some inspiration.

 

[patsnitrovette]

i switched from carb to tpi a few months ago still finishing it up but ill never go back to carb. again, instant throttle response starts when its cold no choke to worry about .I went with a 87 transam setup mass air flow,350 bored 60over, zz4 roller cam,1.6 rockers,sportsman 2 heads ,lower intake ported to match heads upper plenum ported,throttle body massaged, air foil,msd ignition,1 3/4 hooker super comp. headers,into 3 inch sidepipes,700r4 trans. 3.70 gears.,Im still waiting for my custom chip to come,but i took it out the other day and just blipped the throttle and it lights em right up a ton of torque.Hopefully the picture will show up.After i get the chip ill see how she runs then get slp runners to finish it off.Oh and its got a 125 shot of nitrous also.

 

[klb76]

pat,

That seems like a pretty aggressive engine for the TPI system, I would really be interested in how your system works out for you. I also have a 350 bored over with "and aggressive" cam so I pretty much dismissed the TPI system because of that. I have to admit, I shouldn't even be allowed to mention anything about engines because I really don't know what I am talking about, but from my understanding your engine will might have trouble breathing at high RPMs? by the way your pic worked and looks great!

klb

 

[patsnitrovette]

tpi motors are know for running out at usually 5500 and higher ,thats why i ported the lower intake and upper plenum,and ill be switching to the slp runners,it should get me to 6000 and thats where i want to be with this motor.When this thing idles down in gear when warmed up its got a nice lope to it but nothing that would annoy me driving it around.1/8 throttle just lights the tires up like its nothing and thats with a 275/60/15 tire on it too.My brother runs 3 different tpi motors in a gta a camaro and a trans am and he turns 6500 with them,but also has better heads and 1000 cfm throttle body.I truthfully built this motor for torque this time not to be 1/4 mileing like i used too with it.Good luck with whichever way you go.Also in that picture it shows the factory air box which im building a new aluminum one right now to breathe better.