clubstylus

All very interesting info, thanks guys, few things to consider i am still thinking st170 motor but have been thinking duratec also. I am going to have a look at bettering current performance and complete the ecu and tb changeout, will start another thread once i get going.

Quick easy question hopefully, does anyone know the correct equation (from reliable source) for sizing throttle body chokes? Or should i consult my fluid dynamic books? (Not just looking for use 40mm etc want logic behind it please)

Calum

If you don't mind experience over logic, I suggest you speak to an engine tuner about their recommendations. Bailey Motorsport are on the locostbuilders forum and seem pretty helpful as well as having a good reputation. He always suggests 45's for a zetec, but the ports on a ST170 are a good bit larger so 50's may be worth a go. Give him a call.

If you want it to feel really quick on the cheap head down the forced induction route- 200sx for example. Or light, NA with the exhaust on the same side what about K series? Could be expensive to get to ~200 horses though, unless you find a caterham owner pulling theirs out

Or ask the guys with dunnel engines on here what size bodies they have- the are a couple with 240 horse zetecs I think. Which would be close to your 200 @ rear wheels thing, and must be bloody fast

Craig-Chap wrote:If you want it to feel really quick on the cheap head down the forced induction route- 200sx for example.

That's an easy 320bhp right there with a fairly tough engine and all standard apart from larger injectors and intercooler. After that you're looking at a bigger turbo than the standard T28. The only downside is that the SR20DET really doesn't sound great as an engine IMHO, and the standard gearing was very long (mine would do 167mph). Hard to argue with it as a cheap, light and powerful engine though.

200sx might be nice engine choice is down the forced induction route I was trying to avoid though, does it fit? has anyone done it?

Quick update on where I am at weekend came and went in a blur, managed to break away from DIYing yesterday afternoon and spend some time (about 2 hours) on the car. checked for intake air leaks- none, pulled the plugs to replace found 3 and 4 notably leaner than 1 and 2, would say 3 and 4 are good where as 1 and 2 are overly rich. bit of fiddling about but it appears the throttle bodies are far from balanced on tick over alone the left body (3 and 4) wants to eat your hand and the flow through the right body is negligible, is similar once some lower throttle is applied, does suck once higher revs but is still less than other body.

I have the original weber installation guide so I am going to purchase a syncometer as they call it and follow the procedure for throttle Pot and body balance. The POT is mounted on the right hand body (weber manual shows it on the left) which may cause issue as the left hand body is the lead in the throttle linkage, thus if I adjust the right hand stop I am going to struggle to get the left hand to behave in the same way (left to right the balance screw will transfer any force from butterfly spindle right to left a spring damps the movement so it is difficult to control left butterfly opening by adjustment of right hand body throttle stop- hope that makes sense to someone!). The weber manual says to back of stops and ensure throttle is closed and adjust POT to correct 0% voltage- easy enough. Then move on to adjusting LH stop to set the pot until the correct voltage is given- this is where issue arises without the balance adjustment correct and the POT on the RH body this will be difficult, and likewise if I was to go visa versa and adjust the right hand stop due to the linkage this would not transfer through to the left. Think the solution is to either move the POT to the Left hand body- not sure how possible this will be yet or change the throttle linkage to lead with the right ( I say change but will probably mean replace). Anyway rest of the procedure seams straight forward, run engine till warm and balance bodies using syncormeter, use air bypass screws (which until now should have been closed) to give fine adjustment between chokes and body finally adjust tick over correctly piece of cake!

Has anyone done this to weber bodies? I believe from a quick search last night the Jenvy etc bodies do not have the air bypass adjustment I may be wrong though. would like to confirm screw idents, am I correct in thinking the air bypass screw is the wee screw next to injectors on the body?, stop and balance screws are obvious. I should have taken a photo but never got a chance.

So that’s it I really think this should have the car back running like it did in the old days- if not am going to move forward the engine transplant plans, still thinking ST170 but the 200SX has me thinking again.

I have removed the ECU from sale at the moment until I get it working correctly don’t want to pass my problems on else where.

Anyway 10 days to go and will get home and see!

cseng wrote:200sx might be nice engine choice is down the forced induction route I was trying to avoid though, does it fit? has anyone done it?

It does fit - do a search on the forum for posts by a user called Nissanman. He had the SR20DET in his before it died a sad, fiery death.

Rolling road results - viewtopic.php?f=1&t=791

Thats hellish for him would be devistated.

Seems like an expensive swap looking through the details though, also looks to be high believe he said 4" bonnet mods needed, still thinking Zetec at the moment.

Calum

Little update, I have had a look into the linkage sems they are all like this obviously the spring has sufficient rate to allow the movement tof the left by the right throttle spindle (it is quite a stiff spring) so it should just be a case of adjusting as per the weber book but using the RH as the lead body for POT calibration, will update once I have done it, 9 days now!

Will re-ask my question: Has anyone done this to weber bodies? I believe from a quick search last night the Jenvy etc bodies do not have the air bypass adjustment I may be wrong though. would like to confirm screw idents, am I correct in thinking the air bypass screw is the wee screw next to injectors on the body?, stop and balance screws are obvious. I should have taken a photo but never got a chance.

thanks

Calum

Don't know the answer (only ever had Jenveys).

Guess you already have the Zetec version of this doc
http://www.webcon.co.uk/Downloads/K2400 ... 006-01.pdf
ALPHA Performance Kit Fitting Instructions K24001 (DURATEC)
Page 18 Throttle Body (Idle speed) Adjustment Procedure

Or if you want to see how the yanks build a 7, try this...
http://www.secondstrike.com/Technical/S ... Manual.pdf (137 page PDF, larger file)
Pic from that manual attached

I have the zetec manual and the procedure outlined is more or less the same, picture says a thousand words though and the section in the larger manual is very useful although he setup is slightly different than the weber way. Think I may be wrong about the use of the screw on the right though, will need to adjust using the left, still think this is a long winded way of doing it though as will mean you are potentially adjusting the idle based on TPS position when there is an error in the balance link you would then need to adjust the balance link correctly and reset the idle, if I was to set the TPS position using the stop screw on the RH body to obtain the correct TPS voltage and then set the balance to match the LH based on syncormeter reading would save a step, perhaps I am over simplifying.

Again thanks for Info though

Calum

Update- balanced throttle bodies, no real improvement started to look for other problems pulled all plugs and after recent replacement plug 4 looks new no signs of any combustion other three look as you would expect having covered about 100 miles, so concluded running on three honestly didn’t believe it at first the engine was running smoothly and ticking over nicely and although my hearing isn’t the best there was no tell tail noises, my father who had also driven the car didn’t believe it either but the facts don't lie. Anyway on a process of elimination I pulled plug and lead and checked for spark seems strong, compared to the third cylinder and looks identical and it did give me a good belt.

So fuel then- pulled the injector and stuck it in a plastic tub started the engine nice strong pulse of fuel so fearing the worst had to be compression despite no signs of fuel in oil/ water or black smoke .

Couldn’t get the compression tester to fit due to plug thread length on the zetec so after hours on Saturday morning trying to get hold of a either an M14 tap and die to make an adapter or a different compression tester managed to get hold of a Zetec specific adapter, bit of hose with a brass end to suit the longer thread £32! anyhow got that and as a matter of course another set of plugs and some decent quality HT leads despite already proving the spark.

Carried out a compression test all good on every cylinder, decided would change the leads and replace number 4 plug, started it sounded no different, decided to take it for a test anyway and being slightly damp the wheel spin in first second and a wee bit in third showed the difference between a 1350CC engine lugging around a dead piston and a 1800CC engine. I am finally a happy man, I would assume it was the lead and the spark breaking down under compression I have had similar before but the leads did appear new so gave me a bum steer, should have started with the obvious but was struggling to get leads last time home.

Hopefully the 1000+ miles on 3 cylinders have not done any harm, worrying thing is it went through an MOT like this. Had a very fun 100 mile drive back from my parents yesterday. Still planning the Engine swap come winter, had an interesting talk with Weber on Friday they have or are about to launch a fully user programmable ECU which is a direct plug in to existing loom so may go down that route I have to say the customer service of the other ECU manufactures lead a lot to be desired having now waited 3 weeks for a quote with various emails to chase, guys from weber couldn’t have been more helpful.

Hello,

been ages since I was here, still have the car been continually fettering whilst keeping it largely usable, for anyone that may be interested list as follows:

flip front complete with new subframe, catches etc
new balance bar peddle box complete with new bulkhead etc
converted type 9 to hydraulic clutch as needed it for the peddle box (galaxy concentric actuator plus 3d printed spacers backed up with machined standoffs etc cost me £30 all in)
new center consul complete with complete re-wire of dash
battery relocated to boot new main cut off
remote extinguisher in boot
ecu replaced to webcon's new offering so open for mapping
removed mini heater replaced with electric demist
bare metal strip of chassis inside an out up to rear bulkhead repaint with many coats of por 15 all surpluss holes filled
modify chassis so gearbox and engine can drop out the bottom
rewire engine bay
new starter motor
re-plumped brakes replaced flexis as someone had tried to use a 10mm fitting in a caliper that required a banjo fitting
re-plumb fuel system added pre-pump filtration
sure there is many more things I have done between job changes, DIY and getting married will get some photos soon

Jobs planned for this year and maybe further on depending on time and budget (oil industry is not a nice place at the moment):
rear disk conversion sierra disks with MGF rear calipers (cheap)
Capri/ escort upright conversion complete with new custom bottom arms (have a plan) and smaller front disks
maybe 13" wheels
Strip rear end chassis and components and repaint
new seats had sparcos but too wide so not sure what to use wife does not like current seats
tidy and paint body last on my list but there are star cracks in places and some scratches so need to sort and respray entire car