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Yeah, most aftermarket controllers are garbage and kill a sensor in months that lasts ten years in a system designed by a car factory. What’s the best (closest to factory quality) aftermarket controller system?
Separately, any info on that supercharged 850?
i'm also interested for a decent Lambda gauge…. not destroying sensors that quick as i have experienced.
Yeah, the 850... have not being a big joy , problem is the mapping… not the mechanical stuff. It is old school , so demount chips from the 2 ECU's, eprom eraser , and write new mapping…. we are now at 437 HP and 600 NM with 0.4 bar boost.( OEM 300 HP/450 NM ) Goal was 450 HP " as promised" ,but meanwhile we see we loose 0.1 bar boost over the intercooler. Supercharger is a Raptor V, a bit small for a 5 l engine perhaps , but the biggest you can mount in there ( above ) due space…. so we can live with it . Now let me say , with those # 's the 850 already drives well , as BMW should have made it … haha. Without intercooler we should have 450 HP but i do like a safe spinning engine …. 13 HP more are not worth a rebuild ….. eventually .
But we still have some problems as a very bad idle … car likes to stall. Almost all time when decelerating from high rev's , not when done soft gradually , gearing down as to let rpm's go slower...
I'm curious, but can you do a quick recap for those of us struggling to follow along after 2000 posts(!)? I seem to recall that you were hitting a wall on certain aspects of the system with the original engine, so you dropped in a modified engine including lower compression, better manifolds and bigger turbos. It looks like your HP numbers are now meeting or exceeding what you had before, but I haven't gone back to compare. Can you recap the bottlenecks, and whether your current system has gotten past them yet? I'm also interested if you have an estimate of what numbers this version will end up with when it's fully tuned. Would be nice to see before-and-after dyno charts overlaid. Following with interest!!!
Just a quick recap, on 93 E10 pump gas the completely stock ‘87 S4 engine can do about 600-650 rwhp relatively reliably.
Lowering the compression from about 9.5 to about 8.5 and using a little bit bigger cams can get one to about 700-750 rwhp reliably on 93 E10 pump gas. Dropping the compression is more important than changing the cams, if one has electronic RPM specific boost control.
We don't know how much it can do with race gas. I’m hoping for close to 1000 rwhp at 7000 rpm with a flat torque curve at 750 rw lbf-ft, but that’s not a result — it’s an aspiration. Furthermore, it’s not something that the 5-speed driveline can really hold down reliably. So even if it makes a high number, it’ll get detuned back to that 700-750 rwhp level.
The cast exhaust manifolds may be better than the hand fabricated ones, but more importantly they are cheaper to make. The hand fabricating those exhaust manifolds takes an insane number of hand fitting and welding pieces.
The Spec 5 race clutch disc is here. Although it’s not ideal for parallel parking in Boston, it should do the trick for the next set of dyno experiments. After those tests, it’ll probably come off as the engine will be detuned to under 780 flywheel lbf-ft torque limit of Spec 3+ clutch.
When you say "completely stock S4 engine", were you running an OEM headgasket too?
Originally Posted by ptuomov
Yes, in all engines.
And if I recall correctly, with the first motor you were running the original installed-in-late-86-early-87 head gaskets. You didn't "open-up" the motor at all!
And if I recall correctly, with the first motor you were running the original installed-in-late-86-early-87 head gaskets. You didn't "open-up" the motor at all!
Correct.
Opening up these engines without a reason is in my opinion a bad idea. And using aftermarket “performance” components unless it's absolutely proven to be necessary is also a bad idea.
In terms of completely non-stock components, internally the blue engine has Gates Racing timing belt, Porken(ten)sioner, PAC beehive valve springs and retainers, INA lightweight lifters, Ferrea valves (cheap but probably worse than the bent stock valves would have been), non-stock piston rings, pan and pickup spacers, some carefully thought out rubber gates in the oil pan, and heavily modified parts from the I-J windage tray system. The cams are Elgin 65-6 profiles reground on S3 cores. Many of the stock components have been modified, however.
Here’s the flywheel from the stock engine. It took a bit of abuse when we run the previous turbo system with the wastegates bolted shut. There’s a lip so the guess is that clutch was either slipping or on the limits with those runs that were intended and failed to break the stock engine. To be resurfaced.
And here are the flywheel and clutch pieces from the blue engine
The components from the blue engine clutch that just slipped:
Both the stock original and the blue engine’s flywheels will get resurfaced tomorrow morning. The stock engine flywheel is in considerably worse shape, the blue engine flywheel only needs a minimal skim. Better do that, though, to maximize its ability to hold torque.
Have you had a look at the new G-series Garrett turbos?
Considering the shape of your torque curve it is not certain you would need more flow since the stock intake remains the main limitation but perhaps improve spool a little?
Have you had a look at the new G-series Garrett turbos?
Considering the shape of your torque curve it is not certain you would need more flow since the stock intake remains the main limitation but perhaps improve spool a little?
Haven’t looked at new turbos recently. For a pure pump gas car, the blue engine would run better with slightly smaller turbos.
I don’t think the stock intake is any sort of limitation to power production. The way it was ported seems to work very well, I believe it’s distributing pretty much equally. If one were to make improvements on the margin, welding and porting the bottom throttle body element could improve the efficiency a little bit at higher air flow velocities. The exhaust side is much more problematic to cylinder to cylinder distribution than the intake side, and there’s no room to improve there.
The main limiting factors are fuel octane, compression ratio, 180 degree exhaust blowdown interference at low rpms, 90 degree exhaust blowdown interference at high rpms, ability of the driveline to hold up against torque, and the ability of the engine to hold up against rpm. In other words, I’ve got 99 problems but intake ain’t one.
When working the stock S4 manifold, we found the manifold to be very unbalanced runner to runner. Many have seen this and discussed the issue. CFM values ranged from around 260CFM@25" to 285CFM@25" for the one best case runner. After destroying one cast to investigate the flow challenges, we modelled possible porting using clay and testing on the flow bench. After several tests, we came up with a mod plan that got the worst runners to just over 280CFM@25". With this, we left the 288CFM runner pretty much alone. So, after a few thousand spent on flow testing / modeling, we had a port design for a S4 intake to have a range of flow at 280CFM@25" across all 8 runners.
08-29-2019, 09:22 PM
