SR20 5 speed box to 1977 celica speedo, HELP

**craigs stang** · 26-10-2010, 11:39 AM

Hey everyone.
I might have this in the wrong place put here it goes.

I have a 1977 RA28 and have converted it to a Nissan sr20det and 5 speed. Yeah I know "BOOOO" on the nissan stuff but hey its really cheap horsepower

.
Anyway...I have got the 5 speed and converted it from electronic speedo driver to mechanical and amazingly the standard toyota cable fits right up to it.
Now..... the question is, I have know idea of what the speedo will read, but have checked it and it does register.How can I fix it if it does read wrong, is there something I can buy and from where or do I just pull out my dash and redo the face with the right speed

I also am pretty sure that the diff is the 3.9/1 normal celica diff for that model.Can someone tell me if I would be right with this assumption?

.and" Yes" I will blow it apart very easily

but thats not the point right now.Also, what would be the best replacement to use and where do I get it from? Hey, be reasonable with the prices as its a tight budget.

Anyway any info that can be shed on this would be very helpful, oh and any one looking fo info on 1976/77 celicas just ask. I have done some research on these to try and fully understand what bits you can and carn't get anymore.

Thanks for the advice. Craig.

P.S. Check out the club I have started on the Gold Coast, not trying to compete with other clubs, just couldn't find a club based near me that we into the older generation celicas.

**NME308** · 26-10-2010, 01:46 PM

Hi there,
I would imagine that if the speedo is reading off the nissan box right now and you are running a 3.9 diff it should be 'reasonably' close. There are I believe adjustable inline do-hikeys for speedo correction, someone correct ME if I am wrong there!

You could possibly check it (if not currently registered and driveable so as to compare with a known late model car) by using jack stands under the rear axel and dialing up a given rpm in 4th gear and check the speedo reading i.e. with original gearing and tire size 100kph might have been around 3500rpm? (Better check my math here as I don't have the moroso power/speed calculator in front of me right now...) Now if 3500rpm/100kph tire speed on jack stands doesn't sound fun then use less rpm!

Cheers,
Jason

**craigs stang** · 26-10-2010, 04:43 PM

Hey Jason.
Thanks for that.Reckon Ill have to try driving down the street next to my mates new xr6 turbo and compare the speeds as im having "pickup" problems

with the aftermarket tacho I have atm. So carnt tell what rev's im doing.
Anyone else got some ideas?
Oh and where do I get one of the sender thingies to turn a single pulse into 4 so my tacho will read properly or an auto elec. to tell me what wire to splice into to get correct reading.
Cheers Craig

**NME308** · 26-10-2010, 07:31 PM

Hey Craig,
I have occasionally wondered with the new coil on plug or 4 coil or wasted spark deals i.e. distributorless motors if you cant easily create a tacho signal like this:

Splice a wire off each coil ground lead and join these into one goint to your tacho signal input - AND incorporate a directional zener diode in each wire between the splice point and joining these wires into one to prevent the spliced wires crossfiring the coils and worse. This 'should' provide the 4 signals your tacho is needing.

This is simply the musings of my possibly overactive mind - best someone correct me if this cannot/will not work!!!

Cheers,
Jason

**briney** · 27-10-2010, 09:25 AM

i agree with the above post. a few diodes and all should be sweet. don't they have a tach output anyway ? and flexible drive agencies sell ratio boxes to fix up cable speedos. they just need you to do a measured 10km, ( gps ? don't trust road signs.)and tell them how far your odometer said. they sell you a box with the correction in it. worked really well for me. the only problem i can see is, doesn't the computer need some sort of speed signal ? won't it cause some idling problems if it's not there ?

**Ralphie** · 27-10-2010, 12:28 PM

I am not to sure how accurate it was but the readings were close. I used a GPS device in my car and drove along and compared the readings. I have the same setup (sr20 and gearbox) and used a pintara speed sender in the gearbox.

**oldcorollas** · 27-10-2010, 01:51 PM

use a VDO electronic speedo?

or get a mechanical drive adaptor (but may nto be that much cheaper in price)

**craigs stang** · 27-10-2010, 10:29 PM

Originally Posted by Ralphie

I am not to sure how accurate it was but the readings were close. I used a GPS device in my car and drove along and compared the readings. I have the same setup (sr20 and gearbox) and used a pintara speed sender in the gearbox.

Hey Ralphie

,
Thanks for letting me know about your experience with this setup.
I think my mate gave me a R32 Rb20 driver, which should hopefully be about the same as the pintara, because it slipped straight into the box. And I was going to try the gps thing too.
What series sr did you use and what and how did you go with getting a tacho pickup? Atm, I'm trying to research about some "pull up resistor" that I may have to get . I've been told that I need to get one as the signal from the redtop sr turbo, has a week signal from the ecu and its not enough to power the aftermarket units. The pullup resistor is ment to increase the signal so the aftermaket units will work.
Has anyone else had this problem or know if this info is correct?

Anyway hope to here some more good advice soon.
Cheers Craig.

**craigs stang** · 27-10-2010, 10:37 PM

Thanks also for the advice oldcorolla and briney.
Trying to keep it as budget as possiable but want to get it on the road as i got it as a non going rusty shit box and have rebuilt it from the ground up, entirely myself, nearly 3 yrs ago.
In what way will it affect the idle briney? As the only problem I have with the idle atm is running rich because the intercooler piping isn't hooked up.

**Ralphie** · 27-10-2010, 10:55 PM

Hey Craig

I have a s14 black top and only got the car running recently so am using an Apexi RSM for revs at the moment as i picked one up cheaply to drop some skids. I have been in contact with an Auto Elec here in brisbane and they will change the rear of the tacho over for about $250.00 so the cluster will look unchanged.

Looking forward to seeing the rest of your build.

**craigs stang** · 27-10-2010, 11:13 PM

Ralphie, Go to http://4ccustomclassiccelicaclub.webstarts.com/ for the rest of the pics.
hey we got a get together on the 6/11 if your keen?
Should be good, might hav Cav bringing his RA25 along.

**briney** · 28-10-2010, 08:26 AM

Originally Posted by craigs stang

Thanks also for the advice oldcorolla and briney.
Trying to keep it as budget as possiable but want to get it on the road as i got it as a non going rusty shit box and have rebuilt it from the ground up, entirely myself, nearly 3 yrs ago.
In what way will it affect the idle briney? As the only problem I have with the idle atm is running rich because the intercooler piping isn't hooked up.

no worries. i was under the impression that the computer altered the idle if you were moving or not. all you can do is give it a go i suppose.

**craigs stang** · 28-10-2010, 01:40 PM

Hey guys got some great news.
My tacho is now working correctly.
I found out that the signal from the standard sr20det redtop ecu isn't powerful enough for an aftermarket tacho to pickup a signal. That was till now...
I have all the goods on what to do and to what to make this work.
Contact me if you want to know how to fix it.
Thanks for all the advice from everyone.
Cheers craig.