New TR8 Dyno Info

JeffYoung

JeffYoung

New member
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.

tr8.jpg
 
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!
 
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.
 
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.
 
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.
 
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.
 
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)
 
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