New TR8 Dyno Info

[zracre]

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

[Ron Earp]

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

[pfcs]

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

[trd77]

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

[JeffYoung]

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.

[Joe Harlan]

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.
[/b]

Do you have any info on what size the injectors are on this system?

[JeffYoung]

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

[Joe Harlan]

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.

[Ron Earp]

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.

[JeffYoung]

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.

[Joe Harlan]

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.
[/b]

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.

[Ron Earp]

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

[Ron Earp]

[lateapex911]

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

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

[Ron Earp]

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.

[Ron Earp]

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