Individual Throttle Body tech

[Hemi]

i used to call them injected throttle bodies till i realised that sometimes the injectors are not part of throttle arrangement .

thats my cool story for today .

[kpr]

i would think (guessing here) that backtop would use tps as part of the fuel equation.

from my experience its not hard to get a smooth map signal with a bit of messing around. the problem is once you get to a certen throttle opening,(depending on engine and throttle size just when, but we'll say 50% throttle for example). the vacuum flat lines - goes to atmospheric pressure. so from 50% throttle right through to 100% throttle, you have the same amount of fuel when running map vs rpm. so you're either rich at 50% throttle or lean at 100% throttle. now you could add in tps from 50% onwards to add the extra fuel. or just use plain old tps vs rpm. it should drive nicer on map+tps vs rpm. but the extra tuning for what you gain isnt really worth it, over tps vs rpm

The map signal from runners in an ITB setup is shit. A better way is to run a plenum around itbs and take vacuum signal from plenum

how do you mean run a plenum around them? there wont be any vac if your talking a normal plenum ?

[eke_zetec_RWD]

for cold idle up, i use the stock dashpot thing on the 20v throttles. connected to an old tvis solenoid. (3way) have it setup so it cracks the throttle open, when under 60 degrees. then apply vacuum to it at normal op temp, so it pulls back and sits on the normal throttle stop.

4d map was good for when i had the supercharger on it. all the map part of the tune did was add fuel when it was on boost, rest still ran on tps

yea thats what i really need is a 4d map. my dyno man said it was a cunt to tune lol. hes done a excellent job tho!!

[barf]

the 20v itb's vacuum signal isn't shit - it's application is different (they combine AFM and MAP - if am I correct?), actually it has a very precise vacuum sensor position but it is denied a MAP reading when the throttle is closed as noted, there is a small vacuum-sensor hole occluded by the butterflies when shut, if you look closely. will document how we got around this in a new project thread, hope to post that up soon as poss. basically you need idle control system plumbed into your itbs - got photos you can put up rob?

In the case of Megasquirt 2 - TPS without MAP works OK using a speed-density algorithm but you'll likely miss out on features like acceleration enrichment, X-Tau (wall wetting compensation) and have no chance of electronic spark advance derived from manifold pressure. there are two main fuelling algorithms, speed-density (for throttle-body injection ie; V8 holley TBI manifolds) and alpha-N which is the multi-factor algo you want to get it nice and smooth.

out of curiosity, how do you ppl achieve proper spark advance control when the vacuum signal has been neglected? does the Link have a simple RPM + TPS table?

good luck with your project.

[rob]

Got some photos but haven't processed them.. as you know it's pretty ugly but should do the job

While I reckon the path we've chosen is sound, it's all still theory though, we haven't had it running yet. Will be interesting to see how well it works when we're actually tuning the thing.

I'll chuck up a project thread for the starlet once I've got the vacuum hoses for the TB's.

[KKtrips]

^bzzzzzzzt

*individual

Individual - Independent

Tomato - Tomatoe

[Mike-e]

the 20v itb's vacuum signal isn't shit - it's application is different (they combine AFM and MAP - if am I correct?)

eh? not following you. silver top = afm, blacktop = map

[mjrstar]

the 20v itb's vacuum signal isn't shit - it's application is different (they combine AFM and MAP - if am I correct?)

eh? not following you. silver top = afm, blacktop = map

Seems unlikely that this guy would want to run an AFM anyway as it would totally negate the cool factor of the ITB's.

[EURON8]

Seems unlikely that this guy would want to run an AFM anyway as it would totally negate the cool factor of the ITB's.

hehe, nail head etc.

ITBs

55% cause factory intake doesnt fit under engine bay covers

45% Wank factor / sound etc

Some good/confusing reading so far. Will get my head around it eventually.

KPR, Dig one out and PM ya info and ill grab it off ya. Cheers.

[mjrstar]

is there enough room between each ot the t/b's when they are mated up to the head? 1g's are reasonably short for a 6 cylinder.

I guess a front facing plenum could be an option if it was just a matter of getting it operational.

what's that early 80's injected toyota motor that came out in the celicas with the shiny intake pipes that run up to a top mounted manifold. Adapting 2 sets of that shiz to fit to the 1g could well be an option.

As for the TPS just use any old one that can put out the 0-5v reading hell you could even mount it to the throttle pedal if you wanted to..

If you end up going for an older laptop tunable link i can probably dig up a tune from my 1g which would get it running.

[kpr]

out of curiosity, how do you ppl achieve proper spark advance control when the vacuum signal has been neglected? does the Link have a simple RPM + TPS table?

yeh same deal tps vs rpm. plus has barometric correction. example:

http://img.photobucket.com/albums/v178/ ... /ktune.jpg

tps runs acel enrich etc, as per normal.

for tps just run the one already on the throttles.

EURON8: will go dig one out soon.

[mikuni]

is there enough room between each ot the t/b's when they are mated up to the head? 1g's are reasonably short for a 6 cylinder.

I always thought 1g's were just an extended 4age, so if anything will suit the 20v spacing, they would?

what's that early 80's injected toyota motor that came out in the celicas with the shiny intake pipes that run up to a top mounted manifold. Adapting 2 sets of that shiz to fit to the 1g could well be an option.

I think you are talking about a 3T-E, but injected 4K-E's also ran a similar setup. Or was it 3K's? They look so awesome

This would be a good solution to add a bit of low down torque, because 1G's definitely aren't renown for bottom end power and shortening the runners, along with removing TVIS will only add to this problem. Could make for a bit of trouble when towing etc, if that is the desired purpose? Extending the runners to be as long as possible should lower the power band, helmholtz theory etc

[EURON8]

Towing the odd boat / car is one the cards but if it sucks at doing it, i have access to other vehicles for that.

Just want her running tbh.

If i had the parts/dollars/knowledge/skillls id just make a front plenum so i can run all standy stuff,

I can make the ITB stuff relatively cheap atm, computer is only let down in the plan.

Will try make the runners as long as i can, At least the length of the factory ones.

[mikuni]

I can make the ITB stuff relatively cheap atm, computer is only let down in the plan.

Will try make the runners as long as i can, At least the length of the factory ones.

Just make up the manifold with throttles etc to begin with, and a sealed airbox around it, then plumb it all up with the airflow metre and factory ecu/wiring etc and see if/how it runs. Theres probably a number of reasons why it won't run, but also a number of reasons why it could. Will still be getting metered air, the factory TPS on those is more or less a switch too, so shouldn't be too tricky to adjust it, or the afm until you get it running semi-decent. And, if it doesn't run at all, then just get a squirt on there and continue.

The above is more or less my plan, with my next project (or 2).

[UTERUS]

The version 1gge chris has, uses map sensor.

[mikuni]

Oh gays, new tech! Old loom, injectors, afm, cas/dizzy and ecu? I suppose that cost would be equal to megasquirt.

[Abarth]

Hey brad, what injectors and fuel rail did you use on your throttle body manifold?

[mikuni]

Hey brad, what injectors and fuel rail did you use on your throttle body manifold?

Just factory Vectra, although I think it was actually off the single cam engine, not the twincam.

If doing it again, I'd probably go with a custom one, because one of the fittings was a nightmare to find. Was metric and apparently metric fuel/hydraulic fittings don't exist in New Zealand.

[mikuni]

So how does a blacktop 20V work well with MAP sensor, if it's difficult to get any sort of accurate signal from?

How/where/why do they source the MAP signal, I'm guessing they've got all of the runners linked together.

I've managed to get my hands on both sets of ITB's and more importantly as it would seem, the intake manifolds. The manifold is where the both take there vacuum from, and in the case of the blacktop, where I assume, it gets the MAP signal from.

The blacktop is on top, silvertop below. You can see the vacuum runners going up to the top, to a small connector, which I'm assuming is where the pipe attaches for the MAP sensor.

Both intakes have a similar vacuum accumulator setup to supply the booster.

[mjrstar]

I think you are talking about a 3T-E,

Yep that's what i was thinking of..

It must be a bloody fiddly gasket for the blacktop manifold