Square

*** I forgot, I changed the wheels/tires from stock to AFS ZR-1 11" with 315 tires. I will be making another dyno run with the stock wheels/tires to get a true comparison soon! My apologies! ***

I have just completed a TPIS intake manifold, runner, and Adjustable fuel pressure regulator install and I thought I would offer my before and after dyno results to the forum as well as my install observations.

The car is a 1986 coupe. The only significant mod to the engine in the before dyno is a set of TPIS long tube headers and a Random Technologies high flow cat. The air filter & housing, plugs, wires, rotor, cap, and timing are all stock both before and after.

The modifications included the intake manifold, large tube runners, having the plenum ported by TPIS, an adjustable fuel pressure regulator. I had the injectors serviced by Rich at Cruzin’ Performance, I installed new AC Delco plugs (same as before), I installed a new EGR valve, a new IAT sensor, new EGR tube, and new O-rings and gaskets everywhere I took one out.

Stock motor with Headers:



Motor after intake, runners, etc:



As you can see, I gained a net of 11.7RWHP, and 13.6 RWT. Not exactly the 30HP that is advertised for this swap. Maybe, I shouldn’t have gone to the dyno on Friday the 13th! I ran 3 pulls on the dyno with the Air/Fuel sniffer hooked up. The first pull showed the Air/Fuel way rich (I believe they said it was in the 7’s which puzzled them as they said they didn’t think the car would run at all in that condition). I backed off on the regulator and made the second run which is the Graph posted. They thought my stock air filter might be a restriction, so for the third run I removed it. On that run I gained 0.8 HP and lost 5 lb/ft, so essentially, no positive change. I spoke with TPIS about this, and gave them a list of install issues (which I will describe below), and I was told that “all cars are different” and that I might want to replace my mufflers to see if they are a bottleneck. My mufflers are not stock (they have LT-1 tips), and they are pretty quiet, but they were on the car when I bought it, so I do not know what brand they are. I do find it hard to believe that there is 12-15HP hiding in my mufflers, though.

As for the install issues, here they are:

Upon reassembly, the car would start, but unless you held it over 2500 RPM it would not stay running. It would buck, and backfire and die (quite violently). I thought I had the distributor in wrong and I was too chicken to stick my head in the front of the engine to set the timing with it running the way it was. I had the car flat bedded to the local C4 experts, where the polite folks proceeded to get my car back on the road. It turned out to be vacuum leaks, and the timing and distributor were fine.

1) The factory lower runner bolts will not clear the larger tubes from TPIS. TPIS has included 4 “#6” allen head bolts for you to use. The bolts I received were too long and would bottom out before properly sealing the runners. I did not notice this when I installed them as they are long enough to hold the runner to the intake and as I tightened the upper bolts everything seemed firm and leak free. Since the bolts have bottomed out, you can torque them to spec, but they will still leak. The corvette shop removed about ¼ inch from each bolt to solve this problem.

2) EGR valve: The space allotted for the EGR valve in the TPIS manifold is not large enough for the replacement EGR valve I installed (I did not use a GM replacement, so this may not be their fault). Again, it is only slightly off, but enough to cause a vacuum leak. I did not detect this, the shop found it and ground the base down to make it fit properly.

3) The Thermostat housing suffers the same lack of space that the EGR valve does, but I have the stock GM housing. I found this and filed it down to make it fit. TPIS is aware of this and says it is a problem on the 85’s, 86’s, and 87’s. Unfortunately, there is no mention of this in the instructions provided with the intake manifold.

4) One item that is mentioned in the instructions for the intake manifold, is that in step #7 of the installation, it says that you must install the 4 provided spacer washers on the 4 fuel rail towers, or the injectors will be squeezed and run open all the time. I tried to do this, but the bottom of the Plenum would hit the Fuel Pressure regulator before the runner bolts would line up. I called TPIS and they said that on some cars the spacers are not needed and to try it without them. I did this, and it worked, though mentioning that in the instructions would have been nice.

5) TPIS provides a set of small plastic plugs to hold the runner gaskets to the runners to aid in their installation. I found their plugs to be too small and they would simply fall out when tilted downward. I used Permatex’s “The Right Stuff” gasket compound to dab onto the plugs to make them work properly.

Speaking of working properly, “The Right Stuff” is very aptly named, and is a well thought out product. Everything from the quality and consistency of the product to the thought that went into the can/dispenser, I highly recommend Permatex’s “The Right Stuff”.

In TPIS’s defense, I did not have the cold start injector seated properly (causing a vacuum leak) and I did not have the upper throttle body coolant line tightened down (causing a small coolant leak), but even without those, I would have still had to have taken the car to a shop to get it running properly, and for the price paid I would like to see a bit more accuracy in the parts and instructions.

I did call TPIS and politely offered my findings and they were receptive and claimed they would check on the bolts and update the instructions. I also mentioned that many of us here have noticed the front Y-pipe that they sell with their Headers points down too low at the cat, and they claimed that in the latest production run this had been remedied.

Please feel free to offer you insight into my missing 12-15HP and anything I may have overlooked.

Overall, I am not terribly pleased with the performance results, but the car does run well, and with the serviced injectors it idles smooth and no longer has a hard warm start condition.

Sorry for the long post, but I wanted to include all the details for other folks attemping the install.

87 rag

Wow, that is a lot of work and money for such little gains. I hope you get it figured out and this time get a lot for little $$.

Aggravated4life

Aside from the bugs you need to work out,are you saying TPIS claimed a 30 HP increase by just changing the intake and runners alone?
How did they manage that?I have never seen any real world info or documents outside of a companies claim to warrant power gains that much.With a new cam and head work,you can see more.But on a stock engine,a new TPI set up isnt going to do that much.

Hope you get the bugs worked out.

cv67

Hmmm, theres definitely some power missing somewhere, hope you are able to find it. Just for arguments sake (TPIS claims 30 hp increase)... This is a run from my stock 89 with self ported stock intake system (TB to base), w/o headers. Plenty of meat left to port too.

Maybe I missed it, what type of dyno do they use? Believe this was on a dynojet.




What are you running as far as the rest of your exhaust system?

hippy

I guess I was way FKING off when I said a 10hp difference when I thought I got 8 thru the qtr mile. Thanks for an actual dyno sheet.

I'll say it again, the intake isn't going to do sht for $1000.

Square

Hi Bill,

Here are the ads for the items I bought. When I spoke with them on the phone they told me (and I don't have a recording, so it dosen't matter what I claim) that I should see about a 30HP increase.

I am not saying that I'm all pissed off or anything, I just would have liked to see another 12-15 HP/TQ out of the upgrade. However, the car is stronger, and it does run smoother than it did before (though I atribute most of that to the injector service).

Manifold:


Runners:


AFPR:


Mods: if posting these ads/photos is not cool, please remove them.

ckd

I'm sorry for the stupid question but can you please tell me what the loop in the dyno signifies. When I had my other car dynod the operator had no clue. Thanks and again sorry for the stupid question and good luck getting full potential out of your car.

kopbet89c4

That is really awesome your power peaks from 4000-4400 rpms. I bet that there is also some nice torque off idle. Gotta love a nice low revving motor with massive torque though 3000 rpms. I bet it puts you back in your seat nicely!

mseven

To the best of my knowledge all their dyno numbers are based at the crank (fwhp) not at the rear tire (rwhp). They have a regular dyno at their shop but not a chassis dyno, for them to do rwhp numbers they go over to DRM.

Trog

I must have got your HP, sorry about that... :-)

I have close to the same setup you have but while I had mine apart I also slapped in some new rings, cam bearings, timing chain set & oil pump. Everything else on the bottom end was good to go. However, I did a minor port/cleanup job on my 113 heads, new valve springs & matched all ports. Used the 1.6 roller rockers I'd had on there for quite a fewl years. One last trick I did was the thinner Corteco head gaskets to raise compression by supposedly 1/2 a point. The dyno printout says flywheel on the printout, but it was rear wheel readings...

hippy

So you ported a head that flows over the 176cfm stock with a stock lift cam. You had a stock intake that flowed around 198cfm stock.
You now have a head that flows OVER 176 stock. You've raised compression OVER stock and you wonder why you increased your power more than a stock head, cam, compression motor will do with the same intake?
I guess I don't know either.

P.S. Why doesn't your chart show up?

Morley

Well...At least you GOT the manifold from them. I tried ordering one from them a couple years ago and after six weeks and no manifold they gave me a song and dance about problems at the foundry and it would be another week....A week later it was another week...and then another week....told them to keep their non-existant manifold and refund my money (yes, they charged my card as soon as the order was placed).
I found a guy on E bay selling the Accel/LPE manifolds for $387 and it only took a week to get it

TPIS's ad says 22 hp...with a PORTED big mouth intake....I'd bet they have it hoged out pretty good and all gasket matched to get it.

hippy

I guess I don't understand. If a stock head flows 176 cfm with a stock .410 lift cam how much power (HP) is to be extracted from an intake that flows 200cfm, 300cfm, 400cfm?
I'm kinda new to this game and I really don't know.

Morley

You loose power/airflow when ports don't match up exactly, you have casting flash, bumps etc in intake runners and when the air has to make sharp turns...smooth it all out and you are closer to your potential max power. more air in+more air out = more power. In stock form the air isn't flowing as well as it could be.

mseven

I think you understand just fine
I agree with port matching.
As to the original post what I see is if you increase intake cfm only, and the heads flow whatever (stock number 180cfm?). I am sure there is some gain over stock. How much cfm could it possibly flow (or use), or in this case gains could one expect, when only increasing the intake cfm. and changing nothing else.
The TPIS catalog states "there are cylinder heads that will flow much more than the stock manifold can, we designed ....and call it our big mouth. It will give you a 22 hp. increase (when ported ) on a stock 350 CID TPI motor" .
I understand this to mean that they are begining with a modified or different cylinder head, and when intake is ported to match a "cylinder heads that flow much more" (so which stock head flows that much more?) and "gives a 22hp. gain on a stock displacement (non-stroker) 350ci. motor" (used only as reference to C.I.D.).
TPIS probably did achieve those gains mentioned with there TPI, but at the crank. What combination do they reference on intake gains? Do you take this to mean they bolted it on with no other mods., no fiddeling to the tune etc. I just read their catalog and I don't see anything that says that the gain should be at the tire (RWHP) or with headers etc. So if this is the case, then the numbers that the member posted would seem close.
I would call them to ask how exactly did they achieved those numbers.

AGENT 86

Sorry to hear about the lack of improvement Fred
That does seem like a lot of dollars and grief for those minimal gains.
They probably test their product on a motor that flows better all around compared to the stock L98's heads.

cplonner

I have the same numbers just about 220 hp and 280 ft/lbs and I have the edelbrock intake system on my car, plus a bigger cam and vortec heads, long tube headers and full exhuast. My car is running hog rich during idle and lean in the higher rpms and somtimes stalls at idle. Im ordering a chip from alvin on monday and im hoping this will gain my hp potential. Maybe a tune will get you your lost hp?

loiq

WTF?

hippy

Don't even bother trying to figure it out.

hippy

I know.