2 stage with short trumpets

**Celica RA45** · 12-08-2007, 03:08 PM

Was at the dyno yesterday playing around with trumpet lengths .
On with the single stage had 30mm trumpets went up to 65 mm picked up midrange and more power
With the 2 stage system this has changed the length and power was stopping at about 8400 rpm as we are 40mm longer over all .so last week i made up 10 mm ram tubes to fit over the 2 stage units and also played around with inlet cam timming as well
With all this going on we manged to get max power back to 8750 rpm and it hasnt lost any power through the mid range ,in fact we have picked up more agian and also more to the top as well .
So with single stage it made 180 kws at 8750 rpm
2 stage makes 186kws at 8750 and also have made some increases right through the rev range as well.in some places as much as 20 kws through the power range .
Also did a test with the air box on and it lost 3 kws at the top but through the middle we picked up 10 kws with box on ,a little freaky as i would hyave thought it might have killed it more .
another thing i did was put water into the box to see how big it was 12 liters is what the air box took in water so that should help

is there any way to see if a 4 inch pipe is 2 small for a 2 litre motor or should i go up to 5 inch .
we tried air hose off and on didnt make any difference and the ram tubes are 60mm away from the top of the box
the next thing to do after this is ,going dry sump to see if that helps in power and torque ,but that will happen later this year

**Cameron_Datto** · 12-08-2007, 03:42 PM

Got any pics of the intake ?

**roadsailing** · 12-08-2007, 03:57 PM

2 stage as in Ford I6 type manifold? would be interested to see some pics also.

i'm getting closer to quads, i'll just make an educated guess at first, but will be going fairly long on the trumpets (with a common plenum) i'm planning on using 4 inch inlet pipe and filter, 5 inch sounds like overkill, but im not planning on making as much power as you. to test it, i'd put a 3 inch restrictor in the 4 inch pipe, see if you go backwards, are 5 inch filters easy to find? if so just stick one on, doubt there would be a downside.

**Celica RA45** · 12-08-2007, 04:06 PM

2 stage as inboard injectors in the std posi and out boards injectors about 220mm away from the inboards
440 cc in the std place and 720 cc in the out board placement

**roadsailing** · 12-08-2007, 04:11 PM

ah ok, got ya.

do you know how much more power you make top end as a result of the outboards? i take it you did a run on just inboard and just outboard to decide on the switchover point.

**Celica RA45** · 12-08-2007, 07:14 PM

with inboards only 180 kws and with out boards 186 kws so 6 rwkws at back wheels ,as the fuel mixes further out with air it makes more power right through the rev range .it also makes more torque as well

**fixeruperer** · 12-08-2007, 08:52 PM

the fuel would cool down the air and the tubes aswell and that would help a bit.

**Billzilla** · 14-08-2007, 02:38 AM

Originally Posted by Celica RA45

the next thing to do after this is ,going dry sump to see if that helps in power and torque ,but that will happen later this year

Yes you will - You'll find you'll need to retune mostly the mid-range as it'll need more fuel.

Good info there as well!

**Celica RA45** · 14-08-2007, 04:33 PM

my ram tubes are very similar to your pics bill but you have a backing plate right behind .1 does this help air to go in with a flat plate behind ram tube and in a air box situation can it disrupt the air and make it worse

**Billzilla** · 14-08-2007, 07:23 PM

Originally Posted by Celica RA45

my ram tubes are very similar to your pics bill but you have a backing plate right behind .1 does this help air to go in with a flat plate behind ram tube and in a air box situation can it disrupt the air and make it worse

Most of the air actually comes into the trumpets sideways, so the lip around the edge is pretty important. So I run a flat plate to help smooth all that out as much as possible.