Some of you, will know my the story surrounding my 8v engine, in simple terms, the engine works great and will take a beating all day long but it failed to deliver on the Dyno.. So the question is where next? The engine in questions is 2042cc 8v, its a PB/AGG based engine. Hotgolfd items include diesel crank, skimmed pistons, balanced and skimmed intermediate shaft, baffled sump, flywheel, CR ~ 10.9:1 The head is a Shed PB with ported and matched inlet manifold also from the shed, a vagabonds throttle body. a 4 2 1 manifold and a 288 cam with Vernier All this is run on megasquirt using a 2E distributor on the ignition side. Firstly please ignore the 8v turbo developments or non-developments as it currently is, thats a long long term project. Short term I want to build myself an open inducted 8v. Its for fast road use, and wont be going near a track, the part time detailer in me cant stand to see the damage track days do! having driven a friends mates satria GTI on webers, Im sold on the noise and the difference they made to the way the car drives. So using the existing bottom end (pending the results of compression test, I believe everything to be healthy) and an fettled ABA head, different 4 1 manifold, the question is throttles or carbs and head spec, I would love big valves and a big lumpy cam, and webers or throttles But for road use are big valves the best solution? I would like to hit the magic 200 mark, but chasing numbers isnt what Im here for. I was thinking, good port and once over for the head and an inlet to suit. Suggestions on spec for the head are welcome although the bigger question is Webers Vs ITB'S Webers are more 'period' and appear to be a bit cheaper, new pair of 152G 45's plus linkage etc vs new jenveys, injectors rail and regulator etc but what are the real world, in use, differences. the manifold options are not massive, i understand Jason has one or i try and find a cast mangoletsi one. help chaps
i forgot to mention i also have a spare set of std pistons i could use to up the CR further, or i might go for a set of JE's if needed
if it was me I'd go with the throttle body's as it kind of kills two birds with one stone it's a stepping stone to the turbo build one you would learn lots about setting up what ever ecu you get two it would be miles better to live with that weber's
are webers that dificult to live with? my mates car seems ok, i admit i have never been there on a frosty morning trying to get it going, but i havent heard any bad reports. i think jenveys are the logical solution, and could be used on a turbo project, good thinking.
are webers that dificult to live with? my mates car seems ok, i admit i have never been there on a frosty morning trying to get it going, but i havent heard any bad reports. i think jenveys are the logical solution, and could be used on a turbo project, good thinking.
Did you ever get around the 'wall' we hit on the dyno? Did not Jason give some suggestions that was to be tried out first. I would make sure that is covered first and the engine is capable, before adding open induction.
Cost and availability of expertise would swing it for me. Jenveys may be equivalent to webers, but factor in a decent loom and ECU against having to derive a spark for the webers. ITB will be a nicer drive, for sure, day to day, once setup. My tuppenth, as I've had both Jon
i tried several of the suggestions made, different exhaust scorpion ditched jetex fitted, checked the exhaust gaskets were on the right way around, i checked inlet gaskets too, so it left me with 3 options. 1 the engine was emptying the plenum as you suggested, the cam may have been too big for the standard plenum ( i investigated making it bigger but packaging it all was dificult) 2 the exhaust manifold was not suited to the engine. and Jason suggested a 4 into 1. 3 the cam being a schrick copy wasnt a good copy. A chap at work who is a fluid dynamics specialist suggested a buffer vessel in the feed to the MAP sensor to smooth out the waves caused in the inlet, in case an engine pulse was upsetting the sensor, so i even tried that. no noticeable difference. so my updated engine spec should address all three.
It would have been interesting fitting a mild cam like a 272 or even a stock cam and see what would happen. On that dyno, I expected at least a 150bhp@6000 from your combination. Your engine was hitting a wall at high rpm and the calibration was already altered to compensate for a pulsating MAP sensor. So my point is, until that characteristic is fully understood then fitting more hardware to that base it probably not a solution.
Hi Alan Not sure if you've seen it in my JMR blog but Tim Hughes had similar issues to yours...all the right bits but it just wouldn't make the power. Basically, he had several issues: 1...poor exhaust flow from the "sting in the tail" system. .7hp peak gain and "13"hp mid range at the wheels from that alone. I re ported his head of similar heritage, gave the engine a much needed C.R increase, part of which via skimming the block to give a significant squish increase. .it basically didn't have any!...and opened out the manifold flanges that were overlapping the heads exhaust ports. Those mods alone gave another 17hp peak at the wheels and from memory another 9 or 10 mid range...so it's now up to 127 at the wheels. .low 150's...152-153 at the flywheel. Tim's is also on a cam down from yours...276...and the inlet plenum totally std. .no porting at all as there wasn't time, so a couple more hp possible there. It's still on digifant with just a modded std air box. I had to up the fuel pressure to get some in which is a bit crude but it works...its spot on at full load and acceptable at part throttle. Tim reported less fuel use going home than coming down and a more. ."spirited" overall performance from 24hp gain more or less accross the rev range from when I first saw it. So like Eddie has said..it's certainly possible to get yours up in the same ball park, particularly with stand alone fuel and ignition control. As for open induction on a daily driver...hmm...personally I wouldn't, I'd be very surprised if you didn't tire of it in the long term...different ball game for occasional use car tho. I did a throttle bodied MK1 recently as an interim engine to get a crossflow installation sorted...std DX 1781 bottom end but with the squish detailing I do, std valve (39.5 /33) swirl type crossflow head with basically seats and light porting, a 272 hydro cam so we could run std valve springs, and a tubular manifold. .cant remember if it was 4-2-1 or 4-1...ebay shiney special!...and Jetex boxes with the pipework done by the owner. That made high 150's on the engine dyno...I saw 160 flash a few times but called the lowest reading. . .157 I think it was...and later went on to make 140 or so at the wheels (memory fade!) with induction revisions...full story in the pipeline...so mid 160hp now. It pulls a full road trim MK1 up the road on heavy 16's with heavy Recaros pretty quickly! If you were determined to go the open induction route I'd stick with the current cam initially. .carbs or itb's. .or if you persist with the plenum. .which can be made to work..I'd consider dropping to a 276, but "only" once all the details are sorted. .so you may not have to. I've run 296 & 300 cams in 1800/1900's on k-jet. .making 150/145hp respectively. .neither liked part throttle running but were race/track day engines...so plenums and lumpy cams can make power, so yours should be much better on stand alone. It's in there Alan...just got to coax it out!
In fairness who knows what it would measure elsewhere. However the trend with such an engine at Garage Streamline was to expect a stonking 155lbft@4500rpm and about 150bhp@6000rpm on his set up along with the driveability from careful road tuning. Still a challenge I never got to complete. Compared to standard ABF engines at 156bhp@6200rpm that have been tested on that dyno, while the power of Al's 8v would have been projected to just the level of a std ABF unit, the torque would have been significantly more. And you would feel that! Mid range drive feel would be immense! Unfortunately it just hit a wall test driven. By comparison we tested Mike H's Ex slick 50 2.0 motor, also on SEM and that was 149bhp@6000rpm and 145lbft@4400rpm I recall. Very fast 8v.
Jon as i have a couple of Megasquirt units already, the cost incurred would be in mapping, having read up on setting up webers i imagine dyno time would be similar maybe slightly less? the car will be a 2nd car, i might be tempted to use it daily (kind of) through the summer, when i am at home, (i am spending 2-3 days a week in a hire car currently) but in the winter it would put to sleep. its the actual driving of the two that interests me, thanks for the feedback.
i did consider changing the cam to see what happened, i even have a 272 BNIB. ill be honest i lost my desire to fix the engine. and if it needs pulling apart then i want do somethings differently. hopefully i will be getting myself another Mk2 soon and with a different car comes a different engine spec. Time to move on.
It would have been nice to see a proper DIY and fast 8v from this combination and to close the challenge. However if you are happy to move on from that chapter, who am I to complain. Hopefully the next car and engine will only be better!
Totally fair enough Alan...onward and upwards. The basic answers to yr questions are: I'd stick with standard. .ish...valve sizes. Std size is 39.5 on these heads, I've used them to 165hp so far but expect them to cope with 170-175hp. Over that I'd look at Supertech valves @ 40/33. We used those in Tim Moll's (mitlom) 2ltr vag trophy race engine @ 197hp. They fit on the std seat inserts so keeping costs down and would be my overall choice. A budget option can be had by using std 40mm hydro length valves from a PB code head. The stem size is obviously 8mm instead of 7mm but thats splitting hair's. The Supertech valve is lighter and a nicer shape tho but again not much in it. A big valve head is only really worthwhile for a full race engine your chasing over 200hp from...do you really want to spend the best part of 1000 for a head for road use...and thats not including cam, springs & lifters. As for carbs V's injection. Well as you have the management already id prob say injection, tho obviously the parts start to add up. Carbs work fine if set up correctly and mapped ignition makes the job nicer still. Sticking with your 288 cam would see around 180hp on a 40/33 head and make a lively fun road car...and sound the part on carbs or itb's. Go for it!!
Jason, we have both spent time helping Alan. You, with expert 8v race engine advice and I literally with the hands on tuning and development of the ideas. Based on the varying differences we have been seeing on this forum with dyno measurements, I would say the numbers you quoted would not be the same numbers and plots I would see at Theo's. Does not change what you have seen empirically. Pretty confident a typical 175bhp car at yours will be a 155-160bhp@XXXXrpm car at Theo's. Same car, same drive feel, all work done, different machine. When developing an aftermarket calibration a lot of my time is spent, road tuning vehicles to dial in that "fun" into the dynamics of the powertrain. Whether it be a 1.3 Fiesta MK1 or a GT35 EVO8, "fun" is always best dialled in in a real life situation. Unfortunately I cannot do this for everycar as it is very time consuming. I also have been finding in the world of flash port tuning, many a tuned car claiming big peak numbers elsewhere, tend to fail on drive feel and in fact some of my road tuned examples ( with lesser peak measurement at GS) are actually way more responsive. Alan's car from my drive experience of it, initially had that fun factor, that was more than tweaked 1.8 16v and a lightly fettled 2.0 16v, then it died off and hit a wall after 4.5krpm. This was demonstrated by the WOT dyno plot at Theo's. I respect the work and the numbers used to qualify what you do. However let us remember, unless these numbers are correlated to somewhere else by the form of a controlled exercise, they are very specific to developments at AP motorsport/JMR. Make sense what I am saying?
If you want you can borrow my 16v jetex exhaust, if you haven't tried one that size already. It's off my car for a while, and I am literally up the road from you now Alan.
Err...yes and no really. I get what yr saying in terms of feel 100%. The 1800 crossflow car i mentioned above feels very strong on the road for its 165hp or so...one of the quickest I've driven considering the numbers involved and the fact its in a full road weight car with heavy trim, bigger than ideal & heavy wheels and std gearing. In fact it has a longer than std 5th gear at the customers request which it also also lugs through from low revs effortlessly on when in lazy mode. As for Alans suggested spec, id expect it to make the numbers give or take a couple hp at best on that spec...if it only made a real 160hp from open induction, a ported crossflow head, 288 cam on a 2ltr bottom end id give up building engines tomorrow. It wouldn't be a million miles off Tim Moll's in terms of induction and inlet flow, the biggest difference being the cam and lack of forged pistons. If Tim's 197hp was only 177hp he certainly wouldn't have had a 5th overall at Donington and been able to out run ex Leon turbo cupra cup cars down the back straight. I'd see no reason at all for Alans not to make a sub 180hp on GS's rollers on the above spec. In fact Tim Hughes troublesome car made pretty much the same power at AP when we first ran it as both yrself and tsr saw on the respective rollers in terms of wheel power as measured at least. .only the calculated flywheel power is slightly different but only a couple of hp here and there.
On the feel stuff, I have been actually quantifying what that is in terms of g's and then equating those measurements with the dyno's (in this case Theo's DD unit) reported torque. I am sure mitlom's, Tonyb's, your little rocket are well fast 8v track vehicles regardless of where tested. I would never doubt that from some of the footage of these cars in action. Tim's (timo16v) car I just tested on a dyno day. Did not get involved in tuning but like you was helping to give advise. Had pretty dodgy fuel control when tested. If the root cause of fluctuating AFR was fixed, I would not have expected a big jump in peak power, but the torque would have been cleaned up but limited by the poor control from the digifant 2 system. Regardless, this would have made the car more pleasant to drive at WOT. Cam timing tweaks would have added few more torques again. ECU change to SEM, more torque range everywhere, significantly improved drivability with the cam and possible a 145-150bhp motor on those rolls with around 145lbft spread between 4000-4500rpm@WOT. Put your magic on it and a tad bit more again for torque and breathing. Just not massive jumps in numbers at Theo's from tuning NASP motors. You tend to need boost to see that lol On Al's old plenum motor and the fact I knew the old dyno at Theo to a T, 150-155ish bhp@6-6200rpm and around 150-155+lbft at 4-4500rpm is what I expected, to achieve at WOT. Not the 138bhp max which was as a result of an unresolved problem. On open induction 165bhp+@6500rpm maybe and 150lbft@5000-5500rpm + hours to dial in the response. In the right hands those projected numbers would make for a hell of an 8v on the road on what I have seen empirically from both 16v and 8v engines. Ultimately the same trend you would see, just lower measured numbers. I would expect the X flow motor to have some improvement on a counter flow for the above projected output. Still 8v swirl type combustion though! So maybe with with the right bits, 172bhp@6800rpm and 155lbft@5500rpm 8V purists do not like to hear this but, the reality is, for the money and effort you end up with a highly modded 8v that is performing as a standard ABF motor with an aggressive calibration like mine with 174bhp@6200rpm and 163lbft@ 3800-5500rpm! On some of your big power 8vs, I would expect to test, in exactly the same state and tune it came from you at about 180bhp+@XXXX rpm, which is no joke as generally a pretty warm 8v say 2.0 with 272 cam, header etc would achieve just short of 140bhp@6000rpm/145lbft@4000rpm. Stockers did 115bhp@5500rpm for a 2.0 2E and 110-117bhp@5000rpm for Kjet to Digipants. That is the trend I saw over the last 6 years as a trained operator and part time tuning specialist at GS. In addition Gurd's 175bhp@6500rpm Plenum ABF MK1, as tested on those rolles, was able to achieve a 13.7secs@100mph at Santa Pod. Chris Morrisons 2.0 EVO3 at 552bhp@7500 and 477lbft@6000rpm 10.51@131mph. We were told it was impossible to pull those times with the 'low' numbers we reported, but Santa Pod times is just what it is. That is just how that particular dyno rolled lol. Sadly that old 450DS dyno is no more and the guys are in the process of purchasing an even more up to date unit. I am due to shake down a sample unit with my 8L S3 detuned to a standard Audi 210ps calibration (AMK motor) and see how it correlates to the old dyno's data. To be fair though, the time I spend in my hobby on this sort of stuff, is just not commercially viable for a business. I do believe we need to collaborate on a joint venture and do some kind of correlation exercise in the future. PS...They are people wanting a dyno day at yours by the way ...
