New TR8 Dyno Info

Spent a couple of hours on the dyno Saturday morning. This is a .020 over Rover V8, good headers but no dyno work on the exhaust, carbs have been maximized for IT, head has a very rough IT gasket match -- really needs to be cleaned up. In other words, there is probably significant head and exhaust work to do on the car.

Made 160 whp with fueling issues -- car was very lean in the powerband. Need to work on carb jetting looks like. Made 188 torque at the wheels. Didn't get a plot printed. The evil secret on the torque is that it maxes at 3800 rpm and drops fast after 5k. Probably need to rethink running the car to 6k RPM.

With 15 more horsepower at the wheels the car is probably pretty close hp/weight to where I need to be in S, and way up on the RXs on torque. Many other negatives to the car though -- live rear axle, rear drums, crappy front brakes, 85 inch wheel base (can you say spin like a top?).

Interesting car to work on and develop, and the torque/V8 makes it fun to drive. Probably need another year or so development before the car is maxed out, and it might be competitive on "torque tracks" like CMP. We will see.

As a side note, lean means VERY lean > 18:1, off the wide band scale actually. We added fuel to the motor and each time we did hp increased 3-4 hp with every turn of the adjustment. But, the adjustment on the carbs maxed out and about the best she would come to was 17:1, still dangerously lean according to this dyno data system.

Which explains quite a bit, like why it runs so hot under load but will sit at idle on a 95F day and be cool. If feel that if the motor had more timing or more compression at that A/F we might have seen a BOOM in short order. Larger main jets will be in order to capture the hp left in this motor.

But, for a full 10/10th effort there is still more work to be done on the exhaust and heads as Jeff mentioned, plus timing curve issues with full timing advance being lower than expected.

http://www.gt40s.com/images/tr8.jpg

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As a side note, lean means VERY lean > 18:1, off the wide band scale actually. We added fuel to the motor and each time we did hp increased 3-4 hp with every turn of the adjustment. But, the adjustment on the carbs maxed out and about the best she would come to was 17:1, still dangerously lean according to this dyno data system.

Which explains quite a bit, like why it runs so hot under load but will sit at idle on a 95F day and be cool. If feel that if the motor had more timing or more compression at that A/F we might have seen a BOOM in short order. Larger main jets will be in order to capture the hp left in this motor.

But, for a full 10/10th effort there is still more work to be done on the exhaust and heads as Jeff mentioned, plus timing curve issues with full timing advance being lower than expected.
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Sounds like a great step in the right direction! Keep chasing it, and maybe a EGT guage on the next dyno test would help you at the track in chasing this issue at the track. (Make notes of ideal temp from dyno, then replicate at track...or does that only work on rotaries? ;) )

He's got them but haven't had time to install them. We've been chasing more serious problems like running our of gas, distributor being loose, etc. You know, the usual things.

Funny thing is about the lean condition - it is pretty easy to drive a motor and tell when it is really lean, or really rich. The engine doesn't "feel" lean, nor does it act it except for the temperature part which could just be heat build up under load and we need better cooling. We plan to hit the other dyno shop with their equipment to verify the A/F. Carb jetting R&R is pretty serious on the TR8, at least a 4 hour affair, and an hour spent on the dyno could save a lot of time.

R

Oh yeah, who was that guy who ran the car out of gas and forgot to tighten the distributor hold down bolt? We should fire his ass!

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Oh yeah, who was that guy who ran the car out of gas and forgot to tighten the distributor hold down bolt? We should fire his ass!
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How much $ would that save your budget??

;)

Yeah, well, then who would own the TR8?

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Yeah, well, then who would own the TR8?
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Just curious what fuel pump are you running and how much pressure. Also what size fuel line. If you are maxed out on adjustment you may just flat not be moving enough fuel to the carbs. 18:1 should be burning holes in pistons. What do the plugs look like on a cold chop?

The extreme lean condition and propensity to melt pistons at that high of A/F is sort of why it needs re-checking and I halfway don't buy it. I didn't check plugs, but I have before and never saw anything lean when the car was on track with we did some checking with cuts and coast ins.

I do believe that it does need more fuel, based on responses when the slight adjustments that could be done. The fuel pump in the car now is a Holley red and has a regulator providing fuel to the Strombergs at about 4psi. Fuel pressure remained steady during the runs and I didn't feel the car was as lean as the instrumentation indicated.

My gut feeling is that the wide band at the shop was screwed up and this A/F data is crap. Wish we had the EGTs in, maybe we'll put those in here shortly. As for fuel lines I do not know the ID of the various ones on the car Jeff has.

R

Sounds like you guys are having some fun. And not to :dead_horse: but you really need those EGT gauges to get things dialed in. With a V-8, and w/ multiple carbs, that wide-band O2 sensor isn't going to tell you if one bank or the other is lean (unless of course you're running one on each bank). I don't know how many EGT probes you're planning on using, but I would think 1 for each pair of cylinders would be good. I know guys w/ 4-bangers that run one on each hole.

Bill, good point. I have the EGT gauges and thermocouples, just a bit leary of drilling into the headers (which are old, unique and thin). Will do so shortly.

I have two gauges, one for each of the 4 cylinders fed by each carb through the dual plane manifold. Interesting, but one carb feeds cylinders 1 and 5 on the left bank and 4 and 6 on the right. Other carb feeds 3 and 7 and 1 and 8.

Problem is right now I don't know which carb feeds which.....will find out though.

And yes, this whole experience has bene like :bash_1_:

Jeff, lets not bad mouth the TR8. I find it interesting you can't richin it up more. We run very rich on both 8's, mainly to make sure we don't lean out at higher rpms and to run cooler. I run rich enough that my engine builder told me to back it off and not run so rich and screw up oiling problems. Your fuel pump is fine. We just run basic puralator electric pumps and I think about 4-4.5 on the pressure gauge. Are you sure that both carbs are working properly and are balanced? I am not sure which carbs feed what cylinders, because if you look at the intake when the carbs are off, it is open at the top where the carb feed into then divide. It may be more of a timing issue, and you may not be firing at the right time. I always pull my pulgs at the end of each day to see how they look. I just think you should not have a hard time burning rich if the carbs are woring properly and the needles are set correct. I also do not think you need to go to 6,000 rpm, just makes noise and problems. I stay around 5-5500 rpm.

After all that, turns out the sensor at teh first dyno shop was bad. I dynoed at a second Dynojet today, and got a lean condition (15:1) but not nearly as bad as the first.

Sometimes, you have to bad mouth your car. Makes you feel better. But I hear you on all your points. I think the carbs are fine, but I do feel like I'm maxed out with these needles/jets. I will rebalance and see what I can get though.

I am positive, though, that one carb feeds four cylinders and the other feeds the other four. I've of course seen the inside of the intake manifold (many times unfortunately). There is a divider, and the little plastic rings that direct the intake charge down into the heads. There is also the emissions balance "hole" for lack of a better term.

Maybe I should remove the plastic "director" rings to get more of a single plane effect. Don't know. So many things to try on the dyno.

How are the fuelie TR8's compared to the carbed ones??can you update backdate?

The older fuel injection system for the Tr8 is a nightmare. It has more problems than it is worth. We are not allowed to put a new system on.

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The older fuel injection system for the Tr8 is a nightmare. It has more problems than it is worth. We are not allowed to put a new system on.
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The Lucas system on those cars is a bosch based L-jet system with lamda control isn't it? I think I would take that over a pair of Strombergs anyday. The only question I would have about the injection system would be if the stock injectors could handle the fuel required for the HP you are shooting for.

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The Lucas system on those cars is a bosch based L-jet system with lamda control isn't it? I think I would take that over a pair of Strombergs anyday. The only question I would have about the injection system would be if the stock injectors could handle the fuel required for the HP you are shooting for.
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And on the L-jet you can also crank up the fuel pressure quite a bit before it sticks the injectors open...

The intake manifold is what hurts like hell on this car, and the FI manifold is horrible too. Maybe worse than the carb intake. The fuel mixture to the motor is decent as running, I am not saying it is perfect, but we're not going to see a 10 rwhp jump at peak or throughout the curve with FI. The intakes really are bad, and before you say "nah, I'm sure they are not that bad", get one in your hands and have a look. You'll know.

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The intake manifold is what hurts like hell on this car.....
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.....and the heads are pretty restrictive too....

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The intake manifold is what hurts like hell on this car, and the FI manifold is horrible too. Maybe worse than the carb intake. The fuel mixture to the motor is decent as running, I am not saying it is perfect, but we're not going to see a 10 rwhp jump at peak or throughout the curve with FI. The intakes really are bad, and before you say "nah, I'm sure they are not that bad", get one in your hands and have a look. You'll know.
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Yeah your right at 15:1 your not gonna gain anything....clearly the flow of the heads and intake can take more air than fuel. That great big ECU box those old L-jet systems had could take a complete Motec in its own case inside. [attachmentid=328][attachmentid=329]

I guess looking at the two different parts there is no advantage to haveing more port space and direct control over putting fuel right behind the intake valve.. B)

Oh looksie....heres one!!! http://cgi.ebay.com/ebaymotors/ws/eBayISAP...TRK%3AMEWA%3AIT
tempting...very tempting. Id go fuelie!! just for the tunability!

I've not looked at the injection setup closely. I think the heads are the same, it'd be interesting to see what the manifold looks like. It resembles the aftermarket Ford 5L assemblies a bit from the pictures. I'd love to do one with a Motec, Wolf 3D, or some other ECU control. I think if Jeff went down that road though I'd push for a coupe body however, I don't think the open top is doing us any favors on the top end.

R

allegedly there were only 7 V8 coupes legally sold in the states.

that number is wrong. They built about 200 coupes, and most were sold in the US.

Keyrect Morey. Probably more than that (maybe 300 or 350 total) if you count the pre-production 1978 coupes that came over in 1978. They actually are not that hard to find, and sell for cheaper than the convertible. You can get a decent TR8 coupe for $4 or 5k if you look and take your time.

On the FI, the generally accepted wisdom amongst the crowd that races a lot of these cars (in the UK) is that the FI stinks. However, they are comparing it to 4 barrel Holley 390s or Weber 500s, not Zenith Strombergs.

I may pick up an FI system at some point to fiddle with. However, I think the intake is a problem and, as Joe indicated, so too are the injectors. Remember, this is a car that was designed with 135 stock hp. There was not much need for flow on the stock motor.

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Keyrect Morey. Probably more than that (maybe 300 or 350 total) if you count the pre-production 1978 coupes that came over in 1978. They actually are not that hard to find, and sell for cheaper than the convertible. You can get a decent TR8 coupe for $4 or 5k if you look and take your time.

On the FI, the generally accepted wisdom amongst the crowd that races a lot of these cars (in the UK) is that the FI stinks. However, they are comparing it to 4 barrel Holley 390s or Weber 500s, not Zenith Strombergs.

I may pick up an FI system at some point to fiddle with. However, I think the intake is a problem and, as Joe indicated, so too are the injectors. Remember, this is a car that was designed with 135 stock hp. There was not much need for flow on the stock motor.
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Do you have any info on what size the injectors are on this system?

I'll pull the shop manual when I get home.

Well based on an old cross ref. guide the stock injector is 16.1 lbs per hour of fuel. If your target were 225 at the flywheel you would need to run 48 Psi rail pressure to achieve 45B.S.F.C at a 75% maximum duty cycle on the injector. I never run injectors over 80% or under 60% duty when possible...I other words the Lucas bosch system could do the job and I think that's only 5 PSI above stock. I have seen the lucas injectors run a 60
PSI on the V12 jag.

Probably worthless but that's what I can tell you.

It would be interesting to get both manifold conbinations on the flow bench. I've never seen the FI first hand, so it is hard to tell much about it. I know the carb manifold is one of the most tortured I've seen on a SB V8, it is poor. It'd probably need to be cut apart and cleaned all up to make anything of it, of course, all of that being illegal. Hard to say without flow numbers.

Joe, Ron, did some reading on the early FI used on the TR8.

The main problem with the stock system appears to be fuel delivery (which can be fixed) and the AFM (which cannot). The AFM is a "flapper" type that only measures air velocity. It does not measure air denisty or even temperature. Hard to tune it apparently.

Hmm...adding sensors allowed or not? Hadn't thought of that.

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Joe, Ron, did some reading on the early FI used on the TR8.

The main problem with the stock system appears to be fuel delivery (which can be fixed) and the AFM (which cannot). The AFM is a "flapper" type that only measures air velocity. It does not measure air denisty or even temperature. Hard to tune it apparently.

Hmm...adding sensors allowed or not? Hadn't thought of that.
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280z is also a flapper style L-jet system....Nothing more than a potentiometer (sp?) Pluged into a Motec not an issue. I believe you could change the value but why? All it is telling the ECU is how much airflow (by door position) is coming into the engine. When I look at those carbs I see two big reasons to go EFI. I will admit that I would anytime it is allowed because without fuel in those intake runners there is room for more air. Mixing fuel behind the valve will provide a much cleaner way to control mixture all the way through the power curve.

I agree with Joe, with the flapper it'll be directly proportional to airflow and we can use a 3rd party ECU to meter fuel correctly. If the system has a MAP we can make some corrections easily based on its output. There is likey a temp sensor somewhere in the stock system used for fan on off, AC, or something, and, if simply left hanging in the air....well, it'll provide air temp if we want it to.

I think one of the big things will be what that manifold looks like and runner length and flow. Looks like it is a folded design to get those runners long for torque production at a specific RPM band - usualy right where you are driving on a daily basis as a stock car. No, I take that back, it isn't folded, I think it is straight into the upper and then down onto the lower. Looks like the lower has indivdual runners for each port, so, since they are not trying to cross the carbs over and all that crap each runner cross section might be much more favorable than the carb intake.........

Ron

http://www.gt40s.com/images/tr8.jpg

This is the roadster, right? (The coupe is 60 lbs more)

Strong tq, hp yeilds a 16.3/1 pwr / wght ratio

Ride the torque. I don't think there is any ITS car that can point and squirt like this thing can, the problem is, the squirt doesn't last long enough. At CMP this little thing really jumps out of the hole like no other car and actually has a chance since the straights aren't that long. But at VIR etc. that lack of upper end power hurts.

I got the EFI manifold in today - it is better I think.

The lower is not twisted and tortured, it alternates left/right bankand smoothly goes down to ports without all the crimping seen in the carb manifold. The upper is a short breadbox style that feeds all eight pots without indivdual runners, so, it might support some higher RPM use - which is probably useless to us due to cam profile.

Nonetheless, it looks quite a bit better. Maybe in some years an EFI TR8 will live.

R