robot808

Erik, that track video looks like immeasurable fun.

Lizard928

Peak NA HP will be found on these cars at 13.1:1 AFR.......
For a track car, 12.8:1 or 12.5:1 will help it run a little cooler though.

mark kibort

the torque gain is not a gain at all because you dont use the motor really in that area.
but, it shows the CIS system free flows better at the lower flow rates.. after 4000rpm, the ljet with euro and the tuning takes over the helm in a big way..
pretty interesting , since others have said the euro stuff does nothing on the 4.5 liter. clearly it does.

I saw, the 84 with the 4.7 liter make 242rwp, but that was with the euro 82 cams., but it was on a very weak 178rwhp 4.7 before any mods

mark kibort

Not really, 12.6 was optimum 13 lost hp and 12:1 lost hp. the difference was only a few hp though. like 4.

hacker-pschorr

For the 3rd time in this thread - IT'S NOT L-JET!!! It's a full conversion to LH / EZF from a EuroS on a stock US 81.

My 81 has a MAF just like a EuroS.

I've said that and I still will, if that's the only change (intake / TB).

This comparison doesn't prove anything about a bone stock L-Jet car with just an intake / TB change. I wanted to do a before dyno without the supercharger, but I ran out of time.

Multiple people have done the intake swap with direct before / after comparisons and gains were minimal at best.
The exhaust made the biggest difference with my 81 and after the EuroS parts it really didn't feel any faster.

The #1 advantage to this setup that had the most impact on the output is the tunability and dumping the barn door. Which are two things you don't get when doing just the intake swap.

The fact that Mike Simard's 79 made 25 more HP than mine with the only difference being the exhaust cannot be ignored in this discussion.

Richard S

Wow, great results on the '81 L-jet!
























Rich

robot808

danglerb

Red car was LH 2.2? What chips?

225 Drwhp seems like a lot from a stock US 4.5L with just Euro S2 intake and 85/86 manifolds and a Y, but I can see it happening.

mark kibort

Wow sorry, missed that. the point really is, if you have the differences are easy to pick out.
the 79 has the better cam. shows that it picked up power at the low end
the 81 has bigger intake runners, plennum and now the MAF you fitted. makes sense. much more HP.

bolting the euro intake, TB and cams got me 42hp. anyone with half a brain knows the euro 83 cam vs stock US 84 is not worth 42hp. and i had a lot of dyno time on that engine and car. (all the eRAM tests) so, the baseline was pretty cosistant and it was always the same dyno as well.

also worth noting that you 81 has a very restrictive cam. its the worse one of the bunch. I think it shows in the dyno graphs but the intake makes up for a lot up top.

keep in mind, that one 4.5 that was bolted with euro intake, but only the runners. the throttle body was not the same , and who knows what the plennum was at the time bottom line, it wasnt the same as a full euro intake mated out to the US Ljet 4.5.

I think the headers vs 86 manifolds is one thing. the y pipe vs no y pipe, ive tested to be in the 12hp range, but thats with a stock vs 3.5" diameter straight pipe.

Hey, as soon as someone bolts on a pure euro intake on a 4.5, they will see the differences. but its got to be all the stuff. runners, plennum, TB and ported "U".

mark kibort

i had a weak 84, as i said and it was 172 stock no mods. i did exhaust, y pipe and headers and it was 200rwhp. i saw quite a few others that were 220 rwhp and more torque too with the same mods. I think the 4.7 vs 4.5 must be worth about 25hp. makes sense, because when we built scots euro and converted his 250rwhp 4.7, just adding the 300cc to the 5 liter we got 290hp, with no other changes.

another problem comparing old cars is that there is a 20hp variance betwen any same two cars with the exact same specs. kids, these are 30 year old cars. rebuilds, mods, age, all can make the outputs vary greatly.

certainly the exhaust is a huge factor and always has been on the stock older models.

Fabio421

I don't really have alot to add here. I just wanted to go on record to say that I appreciate you sharing these Erik. We don't get too many of these 16v performance threads so it is nice to see.

hacker-pschorr

Thank's Fabio....more to come too

Since yanking my 79 out of an accidental 3 year storage, I forgot out much I love driving that car. This winter some kind of EFI is going on (still deciding) and the blower is moving over. If time permits I hope to do a full N/A tune before strapping on the boost.
Todd also has the plans (in his head) for a 500+ cubic inch air / water IC that will fit in place of the stock airbox. He's jealous us 16V owners have so much real-estate (as he puts it) under the hood.
Nice thing about this IC design is in theory it will work with any supercharger or turbo system and fit all 16V's L-jet or MAF (and safe to assume a custom MAP based setup). The initial design will be made to fit my 81 with the MAF EuroS hardware.

So the 81 will stay N/A for now, but I'll continue to upgrade various parts like the exhaust. I have MSDS headers and a 3" in/out X-pipe for a C5 going on next. Which I suppose means I will have a really nice SS-Y with 85/86 manifolds available.
We'll see how much torque I lose with that setup without boost

December 1st already? I better get to work......

Some day if I'm bored I'll start to upload all the custom stuff that went into the LH / EZF conversion. Like a crank sensor bracket (in the stock location) that could be used as an engine lift point. Where I put the 2nd coil, ignition amps bracket, the rebuilt harness, how Mike (Z) re-wired my fuse / relay panel to emulate a stock car as close as he could etc......
I still need a new tach, odd driving a car that redlines at 3k

IcemanG17

I "heard" that peak NA HP is around 13.1afr....but torque is closer to 12.5.... I gained a bunch in midrange dropping from high 13's to low 13's

mark kibort

it depends on a lot. generally , you will get peak HP and torque at a good power mixture and thats usually in the 12s as high as 13. any higher and you dont get as much power generally. ive seen this with all my early and late cars as welll as lots of others like 911s, and mustangs. you dont loose much going richer than optimal, but lose a lot going lean passed optimial.

as far as comparing dynos from different cars, its feble. the only thing that always seems to reign true is the shapes between cars. again, if you plottled my 84, scots 82, my 79, etc, vs others, there is a huge difference for the same car with the same mods. go ahead, do a search for 928s with the same scale and look at the range. 250rwhp all the way to 275rhp with no mods at all. but they all have the same shape.

what i get out of Erik's dyn runs is that the cams and intake seem to change the shape and proportions of the curves.

hopwood

Hey guys

I have a bunch of dyno runs from my 79 with a euro 4.7 motor 10.4:1 compression. Really interesting to see the improvements from adding 86.5 exhaust manifolds, then adding 3" exhaust single pipe system. Highest I got was 260whp.

The 86.5 manifolds added 24rwhp above 5000rpm (peak increased by about half that but they really opened up the breathing at the top end). When we added the full 3" system peak hp increased by another 16rwhp or so.

I'll try and dig the charts out.

Joel