Hi everyone. I put a 355 TPI in my 79 Monte. I finally got the tranny put in and drove the car around yesterday. Dont get me wrong, the car was quick, but it felt nothing like I expected. Where did I go wrong? The motor is an 88 4 bolt 350 bored 30 over. The motor got a rebuilt stock bottom end. It has a Comp roller cam with .510 lift and a 114 Lobe seperation. This cam has part number
CS-276HR-14. It is a recommended cam in the TPI fuel injection swappers guide. The description says "Highly modified TPI with stock converter." The rest of the motor consists of Accel superram base, Accel 22# injectors, SLP siamesed runners, TPIS 52 MM throttle body, TPIS AFPR set at 48# with the car idling. I hand ported the plenum, took the screens out of the MAF and cut the fins out. I am using the stock heads off the 88 IROC motor(bad idea?). The motor came from an 88 Iroc which had the external coil, so I got an HEI from an 85 IROC and put a bronze gear on it and am using that(bad idea?) I am using Accel header plugs and Accel 8.8 wires. I have a Hypertech Thermomaster chip in the stock ECM. I have the timing set at 12 degrees with the timing connector unhooked. I used a Painless harness with all of the EGR stuff blocked off. The car has Ceramic coated dynomax headers with a mandrel bent 2.5 inch exhaust with 3 chamber flowmasters. The tranny is a rebuilt 2004-R with a 2600 11" non lockup stall(stalls really nice.) 3.73 posi rear from 84 Hurst olds. This seems to be a pretty nice combo in theory but is it in the real world? Any concerns you guys have? The only two I can think of are could I have really corked it with those stock heads? I mean did I make the TPI flow so good that I might have harmed the performance considering I am using the stock heads? The problem is, I hate buying performance parts to fix how the car runs, it is costly and risky. Also is there anything different with the two distributors? I went from the external coil 88 350 distributor to the internal coil disributor one from an 85 IROC. Any thoughts on any of my components would be greatly appreciated. Sorry about the long post, but I got so much $ invested and I dont feel it runs that strong. Thank you for reading.
Jeremy

 

Lots of good parts in your car but not the best combination (yet). I think the heads are the #1 culprit. They'll either need to be ported or replaced with some good aftermarket ones before your car will run up to your expectations.

Given the amount of mods you've made the other thing you really need is a custom PROM. Head over to the DIY PROM board if you haven't yet and read TRAXIONs article on PROM burning. You won't regret it.

 

TPI79,

I'm using essentially the same cam grind (276HR-14) in an LT1 and got very good results. I also increased the stock valve sizes, heavily ported the intake, bowl and runner ported the heads on both sides, raised the port ceilings to clone the LT4 design (without the cost of the LT4 intake), and bumped the fuel pressure about 2 PSIG to max out the enhancements. I'm also running a stock converter and expect to pick up some real gains with the 2,200+ RPM stall unit, but plan to retain the lockup feature.

The TPI by design isn't going to make a lot of torque at higher RPM. The higher stall speed converter may not be supported well by the induction system, even with the larger runners and baseplate, since the restriction at the heads is still there. The heads are designed for flow velocity at low RPM, not volume at high RPM. A few hours under the mill can cure that easily, but you will likely lose some of the low RPM torque that is the signature of the TPI.

You might also have too much fuel pressure. I originally started at +6 PSIG and actually lost performance. +2 PSIG was ideal in my case, and even the stock FPR setting was better than the +6 setting.

I've also had a HyperTech Thermomaster PROM in my TA, and it is now a paperweight. The upgraded GM PROM for my engine actually performs better than the HyperScrap. You may need to do some custom programming to maximize you package. Off-the-shelf PROMs seldom match a customized system well, and usually leave a lot to be desired.

Just some random ideas...

BTW - Whereabout in God's Country is the Monte? I'm FIBbing just across the border, at the extreme southern end of Packerland...

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Later,
Vader
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"Let the bodies hit the floor!"
Adobe Acrobat Reader

 

Thanks for the replies, anyone else have any thoughts? Oh by the way Vader, I am in the mighty town of Chilton. I'll oversee the FIB thing because you are good with the TPI stuff and you help well. Later

[This message has been edited by TPI79MC (edited June 10, 2001).]

 

COOL!

Go about twenty miles straight west and you'll be at my origination point (watch out for the big "wet spot".

I'm still thinking some head/valve work might liberate some power for you.

------------------
Later,
Vader
------------------
"Let the bodies hit the floor!"
Adobe Acrobat Reader

 

the ignition you are using will make it so that all you have is base timing of 12 degrees... I think to make it all work you need the electronic spark control... the heads are definately the other limiting factor... any other thoughts or ammendments???

zroc

 

I am a little confused when you talk about the ignition I am using. I have an ESC in the car, that is still functional isnt it? The only thing I changed ignition wise was the switch to the older coil in cap disributor and it was a direct plug in with the harness I used. Am I wrong here?

 

Welcome to the board. I do not have an answer for your question but I noticed your location was only 20 miles away from me. I would be willing to try and help you with your problem, e-mail me if your interested.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

 

Like Vader mentioned, your heads could use some work. I don't think you mentioned the intake base, so I would suggest some work there, also.

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Bob '89 Ram Air Formula 350
And until that time when death won't wait, let each man rage against his fate. (O'neill)
My car's homepage
Rider's Ride

 

I'm confused. How can you run just 12 deg timing with the computer unplugged? Was this just to set the timing or are you driving the car this way?

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Rob P
89RSconvtZZ4TPI
Edelbrock Hi-Flow Intake
SLP Dual Cold Air Intake
1 5/8" Headers
Semi-Siamesed Runners
MSD6AL/AdjFPR/IROC frnt@rear swaybar/wonderbar/steeringbox/alum drvshaft/ Alston SFC/3:23posi disc rear/MAC LCA/H.Adams Panhard Rod/KYB struts/ shocks/
92Z28convt5spd
71Impala convt 402BB
BETTER DRIVING THRU SUPERIOR HORSEPOWER!

 

I would also extensively port the SLP runners. I used to have them when I had a modified 350 and they did nothing for me. I've read on this board and others that they work very well once their ported.

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Neptune, NJ
White '87 Vette - 383 Superram ported and matched to TPIS big mouth intake, Eagle cast crank, 6"eagle forged rods, srp/je forged pistons, LPE 219 cam, ported heads(2"x1.56" ferrea valves), Comp cams pro-magnum 1.6 rr's, double springs, titanium retainers,Hypertech power coil and cap, 4 bolt block, TPIS headers, auto(trans kit,shift kit),Pro Torque 2600 stall converter, k&N filter, 3.07 rear diff., Silver ZR-1 wheels 17x9 and 17X11

 

I agree...Im in the process of doing a MAJOR Port job on my SLP's and spare plenum..I just finshed siamese the plenum to TPIS large tube runner gaskets and cut the gaskets to siamese them as well.
In the process of siamese the SLP runners even more so..they are now as large as the large tube runners on the gasket match area..just working on porting the wall a few inches down...whew what a lot of work!Its so thick in there.
So far theyre huge now comapred to stock insde and the openings.

Also, with base timing, that seems ike alotof base timing for your set up...what did the cam manufacturer suggest for base timing?
The est connector is then supposed to give you the advance if thats what youre running...maybe 12 base is too much?
12 base then the computer advance might be too much and it will retard the timing somewhat...do you have a scanner to hook up and see whats going on in there?
Also you running the knock sensor?
Believe it or not, the TPI works great in stock form..I mean with all the sensors in place doing their job.
If you over tightened the knock sensor, that could read normal valvetrain noise and pull out ALOT of timing but you wont hear it ping because its not detonating.

Just throwing ideas around...say isnt JakeJr on this board?Hes helped me alot too.

 

Hi again, Bjankuski, your car isnt maroon is it? If it is, I try to chase you down at KK all the time to ask you about your car but I can never catch you And yes your car runs very strong, and sounds just as good! Anyway, to answer a few questions, I have an Accel Superram base, yes I plug the timing connector back in
after setting the base timing, and yes I am running a knock sensor. It seems as though a great majority of you seem to think I need some heads. OK without starting a flame war, now that you know what my combo is, what would be a good set of heads to run? I have heard alot about the Edelbrock 6085 heads, two main things I like is that number 1 they are aluminum and shed alot of weight, and number 2 I like the 60cc Chambers on them that should give me a mild bump in CR. I have also heard good about Dart Iron Eagles, while they have a 64cc chamber which would keep my CR the same, I hear these to be a very good flowing set of heads. What do you guys think, and again, please no flaming with what kinds of heads I should use.
Thank you again

 

My car is all black and I race at KK every Saturday night. I pit in the street pits near a white 1989 350 Formula. You asked a question about heads, I really like the Trick Flow 23 degree heads. I have just purchased a pair of them for the 350 that I am building, and they appear to be excellent heads. I will let you know how well they work once I get the engine installed.

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1988 Formula 5L/5sp 3.45 gears, SLP cold air kit, MAS gutted, TPIS air foil, TPIS AFPR, MAC headers, Mac under drive pulleys, MAC cat back, Relocated MAT.
Best ET street tires 13.85
Best 60 FT street tires 1.930
Best MPH street tires 99.29

 

Hi, I'm sorry, I was really tired when I wrote that, I meant to write black. I am serious too, I know your car, your car has like 3 or 3.5 inch tips on it. I always wanted to talk to you about your car but I could never find you. I wanted to know why it was so quick because I looked at the motor a few times and all I saw different was headers and a AFPR, everything else looked stock. I talked to the guy with that white tall wing there that runs 12.80's on juice and he doesnt have much done to his car either, and he said he was running 13.80's stock. Unfortunately I had a little tranny mishap, like blew up the new tranny I had so the car will be out of commision for awhile, but if you ever want to take a ride or are coming through Chilton, let me know and you could take a look at it and hear it run and let me know what you think. Thanks again for the reply.

 

I'm gonna have to go with the guys saying you have too much base timing. Set it to about 8* base and see if that makes a difference. Pretty easy to do and it's free so give that a try before you go buy a set of $1000 heads.

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1991 Z28 - 350 TPI, T56, McLeod street clutch, LT4 pressure plate, Pro 5.0 shifter, ported plenum & runners, AFPR, Holley Annihilator ignition box and wires, Hooker shorty headers w/o AIR, Flowmaster muffler, homeade ram-air, SSM subframe connectors, Kenny Brown STB, Global West steering box brace, Steve Spohn adjustable torque arm and T56 crossmember

 

Does anyone else have any ideas?

 

I cant find the specs on that cam...
In any case, are the heads ported or what? It almost sounds like you have a mismatch between the heads, TPI and cam. If the duration is more than 220 intake on the cam the ecm probably doesnt like it much either. I think you should start by switching to an 89 chip and go from there. I dont like the idea you have a Hypercrap chip in there either... Ive never been impressed with them.

 

Hi the specs on the cam are as follows,
Intake Exhaust
Valve lift .500 .510
Tappet lift 266 276
Duration 210 220
Lobe seperation 114
I got this right off the cam card, there is other information on it, but I am not sure what you all need. Is this not a good cam?

 

Actually thats a pretty decent choice...
I think the 3.73's are a bit much looking back at your post, TPI's are not high revving engines.