Slow burn project- T1 Speeduino EFI

[Bruce.m]

Hadn’t thought of that possibility

What would be the best layout for boost reacting regulator? The next build will be a type4, & might be turbo.

[Paul H]

The regulator can be mounted anywhere but you won't be able to use the mexican pump/tank as it can't flow enough for a t4 turbo or will be to close to it's limit and maybe can't handle elevated fuel pressure.
Ideally you could make a aluminium pot and mount some in tank fuel pump in that if you have the space and confine the heat to that tank. Warm fuel is actually beneficial for low speed running and when you get on full power the warm fuel is soon used up from the small tank and repleneshed with cool fuel from the main tank

[Bruce.m]

Yup, Mex pump is not going to handle the pressure (up to 5bar). However I do have a spare pump now (that dribbles from the electrical connection) & I have a 1/2 baked plan to swap a different pump into the housing. Might need a feed pump though as gravity feed via 8mm hose might be a restriction?

But getting ahead of myself.

[Paul H]

You could run the return from the filter/reg straight to the tank and use the spare inlet as another 8mm feed

[Bruce.m]

Took a reading. Have around 80miles on the engine so might be a Hp or two as it loosens up & I get the fuel / spark right.

[Paul H]

Is that a real dyno ?

[Bruce.m]

Nope. G-meter based. Allegedly it’s fairly accurate although you need to supply a lot of details such a aero drag (drag coefficient * frontal area), gear ratios, dry weight, fuel load, passenger weights, etc.

Numbers seem believable. It’s stock cam 1641. Heads are autolinea with stock valve that were a freebie as they had dreadful casting flash blocking all the cooling channels. Did careful porting suited to a low lift cam & 30/45/60 valve job, which might explain the torque lift across the range.

[Paul H]

There is a guy on the Samba with an app that seems fairly accurate
I just tested a couple of stock 1600's one was totally stock with a PICT carb and stock exhaust which made 52hp flywheel which is factory number
and a stock mexican engine with 36mm IDF throttles and a 1 5/8 merged race header which made 61hp . The power curves were exactly the same shape

[Bruce.m]

Probably the same one. YouTube guy used it on T1 & T4 engined bugs. Mostly it’s for comparative testing, especially for WOT advance timing.

[Bruce.m]

Changed the temp sensor used for warm-up to the version with a plastic tip. That isolated the sensor from the main body of it which was being cooled by cold airflow. Temp readings are more like I expected now and that should help with the warm-up tuning.

Also activated the overrun fuel cut, to reduce the pops. Fun in the countryside but a bit much for the local villages.

Also fitted the rear 944 sway bar (basic 14mm version) and that’s improved the cornering. Still running some old winter tyres so will be interesting to see how it goes when I fit new tyres for next spring.

[Bruce.m]

Took it on the highway nearby. Up a long slope (for miles) it held 75 on a light throttle and kept up with the local traffic no problem. Pushed it for a short burst and that hit 80-85 without any difficulty. Temps after that run where normal so no overheating issues.

[Paul H]

The 1600 motors will take quite a pounding before overheating I can map a stock 1600 in one go on the rollers without stopping which is not so for others. HP equals heat and the type 1 can only shed so much

[Bruce.m]

I ran MLV log analysis on the highway run. It suggested a load of changes and I picked over the values individually. It took a load of fuel from 85kpa map row which was running rich.

Went out for a run with my brother driving and had to put some of the fuel back in as it was now going lean at high throttle. Not sure I trust the automated MLV analysis after that.

Had a couple of stalls since activating the overrun fuel cut so a little adjustment is needed there.

Mostly though it’s running well enough to use and trust. Brakes are excellent & engine performance suits some fun on twisty rural roads. Sound deadening and interior comes next as it is a loud beast (nicknamed the “hooligan” by my brother). Performance is not enough to overtake slower moving traffic in a situation where my daily would, so the next engine will have that goal.

[wreck]

something to double check it injector voltage correction . I chased my tail for a while because it was not correct for my set up . lower voltage , running richer . I'd do a data log on the way to work in the morning and then put fuel in , then on the way home in the dark with lights on and lower voltage it would be rich .
I'm running about 17 to 1 at low throttle /cruise ,which jumps around a bit ,not sure how much is due to a large overlap cam and reversion in the intake . I still want to get the EGO delay spot on and see how well the open loop works .

[Bruce.m]

Good point on the dead time. I was getting some weird results with my measuring rig so I doubt it’s accurate. So far it’s only been run in daytime with minimal electrical load so I won’t have had that problem yet.

Could also drop the cruise fuelling because there’s more gains to be had there.